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Small extracellular vesicles (sEVs) are crucial mediators of cell-cell communication, transporting diverse cargoes like proteins, lipids, and nucleic acids (microRNA, mRNA, DNA). The microRNA sEV cargo has potential utility as a powerful non-invasive disease biomarker due to sEV's ability to traverse biological barriers (e.g., blood-brain barrier) and become accessible through various body fluids. Despite numerous studies on sEV biomarkers in body fluids, identifying tissue or cell-specific sEV subpopulations remains challenging, particularly from the brain. Our study addresses this challenge by adapting existing methods to isolate sEVs from minimal amounts of frozen human brain sections using size exclusion chromatography (SEC). After ethical approval, approximately 250 µg of fresh-frozen human brain tissue (obtained from Manchester Brain Bank [UK]) was sliced from the 3 donor tissues and incubated in collagenase type 3/Hibernate-E solution, with intermediate agitation, followed by serial centrifugation and filtration steps. Then, sEVs were isolated using the SEC method and characterized by following MISEV guidelines. Before isolating RNA from within these sEVs, the solution was treated with Proteinase-K and RNase-A to remove any non-sEV extracellular RNA. The RNA quantity and quality were checked and processed further for qPCR and small RNA sequencing experiments. The presence of sEVs was confirmed through fluorescence nanoparticle tracking analysis (fNTA) and western blot for surface markers (CD9, CD63, CD81). Size distribution (50-200 nm) was confirmed by NTA and electron microscopy. The total RNA concentration within lysed sEVs ranged from 3-9 ng/µL and was used for successful quantification by qPCR for selected candidate microRNAs. Small RNA sequencing on MiSeq provided high-quality data (Q >32) with 1.4-5 million reads per sample. This method enables efficient isolation and characterization of sEVs from minimal brain tissue volumes, facilitating non-invasive biomarker research and holds promise for equitable disease biomarker studies, offering insights into neurodegenerative diseases and potentially other disorders.

Intraoperative frozen section (IFS) is used with the intention to improve functional and oncological outcomes for patients undergoing radical prostatectomy (RP). High resource requirements of IFS techniques such as NeuroSAFE may preclude widespread adoption, even if there are benefits to patients. Recent advances in fresh-tissue microscopic digital imaging technologies may offer an attractive alternative, and there is a growing body of evidence regarding these technologies. In this narrative review, we discuss some of the familiar limitations of IFS and compare these to the attractive counterpoints of modern digital imaging technologies such as the speed and ease of image generation, the locality of equipment within (or near) the operating room, the ability to maintain tissue integrity, and digital transfer of images. Confocal laser microscopy (CLM) is the modality most frequently reported in the literature for margin assessment during RP. We discuss several imitations and obstacles to widespread dissemination of digital imaging technologies. Among these, we consider how the 'en-face' margin perspective will challenge urologists and pathologists to understand afresh the meaning of positive margin significance. As a part of this, discussions on how to describe, categorize, react to, and evaluate these technologies are needed to improve patient outcomes. Limitations of this review include its narrative structure and that the evidence base in this field is relatively immature but developing at pace., (© 2024 John Wiley & Sons Ltd.)

Aims: To investigate the surgical margin status in patients with prostate cancer who underwent robot-assisted radical prostatectomy (RARP) with intraoperative neurovascular structure-adjacent frozen-section analysis (NeuroSAFE) and evaluate differences compared to patients who underwent radical prostatectomy without NeuroSAFE., Patients and Methods: Between September 2018 and January 2021, 962 patients underwent centralized RARP with NeuroSAFE. A secondary resection was performed in case of a positive surgical margin (PSM) on intraoperative frozen section (IFS) analysis to convert a PSM into a negative surgical margin (NSM). A retrospective cohort consisted of 835 patients who had undergone radical prostatectomy in a tertiary centre without NeuroSAFE between January 2000 and December 2017. We performed multivariable logistic regression to evaluate differences in risk of PSM between cohorts after controlling for clinicopathological variables., Results: Patients operated with NeuroSAFE in the centralized clinic had 29% PSM at a definitive pathological RP examination. The median cumulative length of definitive PSM was 1.1 mm (interquartile range: 0.4-3.8). Among 275 men with PSM, 136 (49%) had a cumulative length ≤1 mm and 198 (72%) ≤3 mm. After controlling for PSA, Grade group, cribriform pattern, pT-stage, and pN-stage, patients treated in the centralized clinic with NeuroSAFE had significantly lower odds on PSM (odds ratio [OR]: 0.70, 95% confidence interval [CI]: 0.56-0.88; P = 0.002), PSM length >1 mm (OR: 0.14, 95% CI: 0.09-0.22; P < 0.001), and >3 mm (OR: 0.21, 95% CI: 0.14-0.30; P < 0.001)., Conclusion: This study provides a detailed overview of surgical margin status in a centralized RP NeuroSAFE cohort. Centralization with NeuroSAFE was associated with lower PSM rates and significantly shorter PSM cumulative lengths, indicating improved control of surgical margin status., (© 2024 The Author(s). Histopathology published by John Wiley & Sons Ltd.)

Background: During sentinel node navigation surgery in patients with gastric cancer, intraoperative pathologic examination of sentinel nodes is crucial in determining the extent of surgery. In this study, we evaluated the feasibility and accuracy of intraoperative pathologic protocols using data from a prospective, multicenter, randomized trial., Methods: A retrospective analysis was conducted using data from the SEntinel Node ORIented Tailored Approach trials from 2013 to 2016. All sentinel lymph nodes were evaluated during surgery with hematoxylin-eosin (HE) staining using a representative section at the largest plane for lymph nodes. For permanent histologic evaluation, sentinel basin nodes were stained with HE and cytokeratin immunohistochemistry in formalin-fixed, paraffin-embedded (FFPE) sections and examined with HE for three deeper-step sections at 200-μm intervals. The failure rate of identification by frozen section and the metastasis rate in non-sentinel basins were investigated., Results: Of the 237 patients who underwent sentinel node basin dissection, 30 had lymph node metastases on permanent pathology. Thirteen patients had macrometastasis confirmed in frozen sections as well as FFPE sections (failure rate: 0%). Patients with negative sentinel nodes in frozen sections but micrometastasis in FFPE sections had no lymph node recurrence during the follow-up period (0%, 0/6). However, in cases with tumor-positive nodes in frozen sections, metastases in non-sentinel basins were detected in the paraffin blocks (8.3%, 2/24)., Conclusions: The single-section HE staining method is sufficient for detecting macrometastasis via intraoperative pathological examination. If a negative frozen-section result is confirmed, sentinel basin dissection can be performed safely. Otherwise, standard surgery is required., (© 2024. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Key Message: Immunofluorescence staining with frozen sections of plant tissues and a nest tube is convenient and effective, and broadens the applicability of immunofluorescence staining. Immunofluorescence staining is an indispensable and extensively employed technique for determining the subcellular localization of chloroplast division proteins. At present, it is difficult to effectively observe the localization of target proteins in leaves that are hard, or very thin, or have epidermal hair or glands with the current immunofluorescence staining methods. Moreover, signals of target proteins were predominantly detected in mesophyll cells, not the cells of other types. Thus, the method of immunofluorescence staining was further explored for improvement in this study. The plant tissue was embedded with 50% PEG4000 at -60℃, which was then cut into sections by a cryomacrotome. The sections were immediately immersed in fixation solution. Then, the sample was transferred into a special nested plastic tube, which facilitated the fixation and immunofluorescence staining procedures. The use of frozen sections in this method enabled a short processing time and reduced material requirements. By optimizing the thickness of the sections, a large proportion of the cells could be well stained. With this method, we observed the localization of a chloroplast division protein FtsZ1 in the wild-type Arabidopsis and various chloroplast division mutants. Meanwhile, the localization of FtsZ1 was also observed not only in mesophyll cells, but also in guard cells and epidermal cells in a lot of other plant species, including many species with hard leaf tissues. This method is not only easy to use, but also expands the scope of applicability for immunofluorescence staining., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Staining frozen sections is often required to distinguish cell types for spatial transcriptomic studies of the brain. The impact of the staining methods on the RNA integrity of the cells becomes one of the limitations of spatial transcriptome technology with microdissection. However, there is a lack of systematic comparisons of different staining modalities for the pretreatment of frozen sections of brain tissue as well as their effects on transcriptome sequencing results. In this study, four different staining methods were analyzed for their effect on RNA integrity in frozen sections of brain tissue. Subsequently, differences in RNA quality in frozen sections under different staining conditions and their impact on transcriptome sequencing results were assessed by RNA-seq. As one of the most commonly used methods for staining pathological sections, HE staining seriously affects the RNA quality of frozen sections of brain tissue. In contrast, the homemade cresyl violet staining method developed in this study has the advantages of short staining time, low cost, and less RNA degradation. The homemade cresyl violet staining proposed in this study can be applied instead of HE staining as an advance staining step for transcriptome studies in frozen sections of brain tissue. In the future, this staining method may be suitable for wide application in brain-related studies of frozen tissue sections. Moreover, it is expected to become a routine step for staining cells before sampling in brain science.

Context.—: In the United States, review of digital whole slide images (WSIs) using specific systems is approved for primary diagnosis but has not been implemented for intraoperative consultation., Objective.—: To evaluate the safety of review of WSIs and compare the efficiency of review of WSIs and glass slides (GSs) for intraoperative consultation., Design.—: Ninety-one cases previously submitted for frozen section evaluation were randomly selected from 8 different anatomic pathology subspecialties. GSs from these cases were scanned on a Leica Aperio AT2 scanner at ×20 magnification (0.25 μm/pixel). The slides were deidentified, and a short relevant clinical history was provided for each slide. Nine board-certified general pathologists who do not routinely establish primary diagnoses using WSIs reviewed the WSIs using Leica Aperio ImageScope viewing software. After a washout period of 2-3 weeks, the pathologists reviewed the corresponding GSs using a light microscope (Olympus BX43). The pathologists recorded the diagnosis and time to reach the diagnosis. Intraobserver concordance, time to diagnosis, and specificity and sensitivity compared to the original diagnosis were evaluated., Results.—: The rate of intraobserver concordance between GS results and WSI results was 93.7%. Mean time to diagnosis was 1.25 minutes for GSs and 1.76 minutes for WSIs (P < .001). Specificity was 91% for GSs and 90% for WSIs; sensitivity was 92% for GSs and 92% for WSIs., Conclusions.—: Time to diagnosis was longer with WSIs than with GSs, and scanning GSs and uploading the data to whole slide imaging systems takes time. However, review of WSIs appears to be a safe alternative to review of GSs. Use of WSIs allows reporting from a remote site during a public health emergency such as the COVID-19 pandemic and facilitates subspecialty histopathology services., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

Objective: To compare the staining quality between rapid hematoxylin and eosin (H&E) staining and routine H&E staining of frozen breast tissue sections., Methods: In this cross-sectional observational study, 120 frozen breast tissue sections were randomly assigned to rapid or routine H&E staining ( n =  60 per group). Rapid H&E staining used a 7:1 mixture of modified Gill's hematoxylin and alcohol-soluble 1% eosin Y. The staining quality of each section was evaluated and scored. A score of >7 was considered excellent, a score of 6 to 7 good, and a score of ≤5 poor., Results: The staining time for rapid staining was approximately 3 minutes, whereas that of routine staining was approximately 12 minutes. There were no significant differences in the staining quality scores or proportions of sections in each grade between the two staining methods. The proportions of sections that were classified as excellent or good were 96.7% and 98.3% for rapid and routine staining, respectively., Conclusions: In frozen breast tissue sections, rapid H&E staining may provide staining quality that is comparable to that of routine staining, while markedly reducing the staining time., Competing Interests: Declaration of conflicting interestsThe authors declare that there is no conflict of interest.

Background: The aim of this clinical trial was to compare Fluorescein-stained intraoperative confocal laser endomicroscopy (CLE) of intracranial lesions and evaluation by a neuropathologist with routine intraoperative frozen section (FS) assessment by neuropathology., Methods: In this phase II noninferiority, prospective, multicenter, nonrandomized, off-label clinical trial (EudraCT: 2019-004512-58), patients above the age of 18 years with any intracranial lesion scheduled for elective resection were included. The diagnostic accuracies of both CLE and FS referenced with the final histopathological diagnosis were statistically compared in a noninferiority analysis, representing the primary endpoint. Secondary endpoints included the safety of the technique and time expedited for CLE and FS., Results: A total of 210 patients were included by 3 participating sites between November 2020 and June 2022. Most common entities were high-grade gliomas (37.9%), metastases (24.1%), and meningiomas (22.7%). A total of 6 serious adverse events in 4 (2%) patients were recorded. For the primary endpoint, the diagnostic accuracy for CLE was inferior with 0.87 versus 0.91 for FS, resulting in a difference of 0.04 (95% confidence interval -0.10; 0.02; P = .367). The median time expedited until intraoperative diagnosis was 3 minutes for CLE and 27 minutes for FS, with a mean difference of 27.5 minutes (standard deviation 14.5; P < .001)., Conclusions: CLE allowed for a safe and time-effective intraoperative histological diagnosis with a diagnostic accuracy of 87% across all intracranial entities included. The technique achieved histological assessments in real time with a 10-fold reduction of processing time compared to FS, which may invariably impact surgical strategy on the fly., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)

Background: Fluorescence-based confocal microscopy (FCM) can be used to create virtual H&E sections in real time. So far, FCM has been used in dermato-, uro-, and gynecopathology. FCM allows the creation of a completely digitized frozen section, which could potentially replace conventional frozen sections in the future., Objective: The aim of the current work is to implement FCM technology as a component of fully digitized processes in the pathological workflow. For this purpose, the current use of FCM in liver transplant pathology will be extended to other disciplines such as urology and otorhinolaryngology., Materials and Methods: The FCM technique continues to be used prospectively on native tissue samples from potential donor livers. Conventional frozen sections are used comparatively to virtual FCM scans., Results: The data show a nearly perfect agreement for the detection of cholangitis, fibrosis, and malignancy, and a high level of agreement for, e.g., macrovesicular steatosis, inflammation, steatohepatitis, and necrosis between virtual FCM scans and conventional routine diagnostic frozen sections., Conclusion: Since the availability of time- and cost-intensive frozen section diagnostics in the context of transplant pathology in continuous operation (24/7) is now only established at very few university centers in Germany due to an increasing shortage of specialists, the use of FCM could be an important building block in the current process leading towards a fully digitized pathology workflow and should thus be extended to various disciplines., (© 2024. The Author(s).)

Purpose: This study was a retrospective and nonrandomized study to assess the safety and reliability of identifying the surgical margin in breast cancer breast-conserving surgery (BCS) by using intraoperative ultrasonic location and specimen mammography instead of traditional intraoperative frozen pathological section., Methods: Among the patients who underwent BCS from May 2019 to October 2021, according to the different methods of evaluating the intraoperative margin, 104 breast cancer patients were included in the frozen edge group, 53 breast cancer patients were included in the freeze-free group, and the surgeon judged whether extended resection was needed based on the results of pathological section or evaluation of intraoperative ultrasound and mammography. The surgical margins of the two groups were judged by postoperative pathological results as the gold standard., Results: The median waiting pathology results time in the frozen edge group was 64 minutes, while the waiting time in the freeze-free group was 30 minutes, and the difference was statistically significant (P < .0001). The postoperative pathological results showed that the positive rate of the surgical margin in the frozen edge group was 0.96%. The coincidence rate of intraoperative frozen and postoperative pathological results was 99.04%. The coincidence rate between intraoperative mammography and postoperative pathological results was 100%., Conclusions: In BCS, the method of using intraoperative staining markers combined with mammography to evaluate the resection margin is highly accurate, reliable, economical and convenient, and at the same time reduces the waiting time of the operator during the operation. However, this was not a randomized controlled study, and there was patient selection bias, and its safety needs to be confirmed by long-term follow-up. In the future, it is expected to become the mainstream means of evaluating., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Sentinel lymph node (SLN) is the first lymph node to drain the lymph from a particular region involved by cancer. The commonly performed intraoperative methods for SLN evaluation are touch imprint cytology (TIC) and frozen section (FS). The present study aimed to determine the sensitivity, specificity and accuracy of TIC and FS with histopathological diagnosis as gold standard., Materials and Methods: The nodes were bissected along their long axis and wet surface was imprinted on to clean glass slides followed by toluidine blue and rapid Papanicolaou staining. Subsequently the lymph node slices were cut at three levels using the cryostat machine and stained with Hematoxylin and eosin stain. The cytological and FS findings were compared and the specificity, sensitivity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of TIC and FS was evaluated taking histopathological diagnosis as gold standard. In addition, pooled sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for touch imprint cytology and frozen section were assessed for the studies included in the meta-analysis., Results: The specificity, sensitivity, diagnostic accuracy, positive predictive value and negative predictive value of touch imprint cytology were 100%, 88.2%, 90%, 100% and 60% respectively. The specificity, sensitivity, diagnostic accuracy, PPV and NPV of frozen section were 100%, 94.1%, 95%, 100% and 75% respectively. The sensitivity of TIC and FS for detection of micrometastasis was 60% and 80% respectively. The pooled sensitivity and specificity for touch imprint cytology were 85.24% (95% CI, 83.46%-86.90%), and 98.99% (95% CI, 98.69%-99.23%) respectively. The pooled sensitivity and specificity for frozen section examination were 90.45% (95% CI, 85.15%-94.34%), and 100% (95% CI, 99.24%-100%) respectively., Conclusion: Even though the sensitivity of FS was better than imprint cytology in detection of micrometastasis, TIC is a rapid inexpensive technique which can be utilized in remote areas in absence of cryostat machine. The sensitivity of the two techniques with respect to detection of macrometastasis was comparable. This meta-analysis highlights the accuracy of the touch imprint cytology and frozen section examination in the intra-operative detection of malignancy in breast cancer.

Background: Central nervous system (CNS) lymphomas, either primary or secondary in origin, are rare malignant tumors affecting the brain, spinal cord, or leptomeninges. Diagnosis of CNS lymphomas is complicated by their diverse clinical presentations, radiological features, and histopathological characteristics. Although frozen section (FS) analysis is commonly employed for various CNS tumors, its role and accuracy in CNS lymphoma diagnosis are less explored. In this study, we conducted a comparative analysis to assess the impact of knowledge of preoperative imaging on enhancing the accuracy of FS diagnosis in CNS lymphomas., Methods: Data collection involved a retrospective review of CNS lymphoma patients from January 2009 to August 2021. Patients who underwent intraoperative consultation were included, excluding those with prior cortisone treatment. The dataset incorporated patient demographics, classification as primary or secondary lymphoma, radiological preliminary diagnoses, FS diagnosis, and permanent section diagnosis. We employed various archived materials, including FSs, touch imprint slides, crush cytology slides, H&E-stained sections, and immunohistochemical stains, and re-evaluated all slides for diagnostic validation., Results: Our study included 25 patients, of whom 60 % were female and had a mean age of 56.5 years. Preoperative radiology data were available for 80 % of cases, with preliminary diagnoses commonly including lymphoma and/or metastasis. Intraoperative consultation results indicated lymphoma in 18 (72 %) patients, with discordance observed in 28 % of cases when compared to permanent section diagnoses. Most permanent section diagnoses were diffuse large B-cell lymphomas (92 %), with the remainder being T-cell non-Hodgkin lymphoma (4 %) and follicular lymphoma (4 %). Intraoperative misdiagnoses were significantly associated with the absence of knowledge of preoperative imaging., Conclusion: Our study demonstrates the reliability of FS diagnosis for CNS lymphomas during surgery, with a favorable complete concordance rate of 72 % when compared to permanent diagnoses. Importantly, lack of knowledge of preoperative imaging significantly impaired diagnostic accuracy in FS, emphasizing the need for close collaboration between pathologists and radiologists., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aim and Objectives: To estimate and evaluate the optimal thickness of tissue section for skin and dermal appendages intra-operatively and to compare the morphology and architecture of the epidermis and its appendages at 7 and 10 microns., Methodology: After obtaining clearance from the institutional human ethical committee, 101 skin margins were prospectively analyzed using a two-step embedding technique. After multiple trials and errors, 7- and 10-micron thicknesses were selected for the present study. Artefacts, staining characteristics, cellular morphology, cellular outline, and nuclear outline were assessed and scored as unacceptable or acceptable. The data were entered in a Microsoft Excel spreadsheet and analyzed using SPSS software., Results: There was a statistically significant difference between the sections obtained at 7 microns and 10 microns (p-value: <0.001), the latter were better in all the parameters analyzed. However, no difference was noted in the characteristics of the dermal appendages (p-value: >0.05)., Conclusion: While mucosal margins can be obtained at the usual 5-7 microns, the same thickness is not optimal for skin margins intra-operatively. Frozen sections for the skin margins may be set at 10 microns, to save time, minimize artefacts, and for better readability.

Objectives: Intraoperative frozen-section evaluation is a valuable technique for detecting positive margins intraoperatively for oral squamous cell carcinoma. We conducted this study to determine the diagnostic accuracy of frozen section in detecting margin status and the effect of tumor grade and stage on diagnostic accuracy., Results: A total of 251 biopsy-proven cases of oral squamous cell carcinoma were included in this study. The tissue specimen resected during surgery was sent to the laboratory for frozen section evaluation. The frozen section results were then compared with the permanent section results to determine the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy. The mean age of the patients included in the study was 51.65 ± 10.03 years, with male predominance (55.4%). The overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of frozen section were 88.81%, 94.84%, 95.20%, 88.10%, and 91.63%, respectively. We conclude that frozen section is a useful technique in determining the margin status intraoperatively in oral cancers, with high diagnostic accuracy. Moreover, certain clinical parameters such as age, gender, disease duration, and tumor stage and grade appear to affect the diagnostic accuracy of frozen section., (© 2024. The Author(s).)

Objectives: Intrapathology consultation is recommended for complex cases during frozen section (FS) as routine practice. In our institution, solicited second opinions were traditionally provided by in-person consultation (IPC). Whole-slide imaging (WSI) was implemented in 2018 as an alternative but replaced by videoconferencing in 2020. Here, we assess the accuracy of remote FS consultation using these digital modalities vs IPC., Methods: Gynecologic FS cases over a 4-year period overseen by 2 intraoperative consultants were grouped by consultation method: (1) IPC, (2) WSI, and (3) videoconferencing. Accuracy was determined by concordance between the FS and final report diagnoses. Turnaround time between the 3 groups was analyzed using SPSS statistical software (IBM)., Results: Using WSI and videoconferencing, 100% concordance was observed, while the IPC group had a 98.5% concordance rate. Videoconferencing, however, showed longer turnaround times (mean, 45.59 minutes) than IPC (mean, 33.36 minutes). Although turnaround time positively correlated with the number of FS specimens, blocks, and H&E slides per case, no statistically significant differences in the number of specimens, blocks, and H&E slides generated were found among the consultation methods., Conclusions: Even though turnaround time using videoconferencing is longer, the accuracy of WSI and videoconferencing for remote FS consultation is equivalent to IPC. It is therefore a safe method for conducting intrapathology FS consultation in challenging surgical cases., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context.—: Intraoperative diagnosis by frozen section is a mainstay of surgical pathology practice, providing immediate feedback to the surgical team. Despite good accuracy with modern methods, access to intraoperative surgical pathology with an appropriate turnaround time (TAT) has been a limiting factor for small or remote surgical centers, with negative impacts on cost and patient care. Telepathology offers immediate expert anatomic pathology consultation to sites without an in-house or subspecialized pathologist., Objective.—: To assess the utility of live telepathology in frozen section practice., Design.—: Frozen section diagnoses by telemicroscopy from 2 tertiary care centers with a combined 3 satellite hospitals were queried for anatomic site, TAT per block, pathologist, and concordance with paraffin diagnosis. TAT and concordance were compared to glass diagnoses in the same period., Results.—: For 748 intraoperative diagnoses by telemicroscopy, 694 had TATs with a mean of 18 minutes 56 seconds ± 8 minutes 45 seconds, which was slower than on glass (14 minutes 25 seconds ± 7 minutes 8 seconds, P < .001). Twenty-two (2.89% of available) were discordant, which was not significantly different from the on-glass rate (P = .44) or categorical distribution (P = .31). Two cases (0.27%) had technical failures., Conclusions.—: Although in-person diagnoses were statistically faster, the great majority of telemicroscopic diagnoses were returned in less than 20 minutes. This remained true through numerous pathologists, pathology assistants and/or technicians, different hospitals, and during a combined 6 years. The concentration of discordant diagnoses among relatively few pathologists suggests individual comfort with telepathology and/or frozen section diagnosis. In rare cases, technical issues prevented telemicroscopic diagnosis. Overall, this justifies continued use and expansion of telemicroscopic services in primary intraoperative diagnoses., (© 2024 College of American Pathologists.)

Background: Intraoperative frozen section histopathology (IFSH) in sinonasal and skull base surgery although widely used is not well studied., Methods: We reviewed a database of sinonasal and anterior skull base tumors, between 1973 and 2019, and identified 312 suitable operative cases. Clinicopathologic data was collected and analyzed, in addition to descriptive data for histopathological reports classified as "ambiguous," or "limited/insufficient-quality/quantity.", Results: Overall, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for IFSH were 90.2%, 97.5%, 94.2%, 95.6%, and 95.2%, respectively. IFSH for adenocarcinoma, salivary carcinoma, and SCC all demonstrated a better clinical utility with a sensitivity of 90% or greater, while it was less than 90% for esthesioneuroblastoma, melanoma, and sarcoma. Other factors such as unclear reporting, poor quality specimens, or limited quality specimens were shown to lower diagnostic performance. Based on limitations identified, we proposed a novel IFSH reporting algorithm to improve IFSH in sinonasal and skull base surgery., Conclusions: IFSH is an accurate and clinically useful technique in sinonasal and skull base surgery patients; however, limitations exist., (© 2023 Wiley Periodicals LLC.)

Background and Purpose: Hepato-pancreato-biliary (HPB) surgeries are one of the most challenging and complex procedures. Intraoperative frozen section (IFS) diagnosis plays a pivotal role in management decisions. Comprehensive large cohort studies evaluating utility of IFS in HPB malignancies are lacking. This study aimed to evaluate the accuracy of frozen section analysis and to analyse discrepancies and impact of IFS on the surgical decisions., Patients and Methods: This was a retrospective study of IFS received for the HPB specimens between years 2009 and 2021. The results were compared to the permanent sections to evaluate diagnostic accuracy, sensitivity and specificity. Indications, disagreements and impact on the surgical management were analysed., Results: A total of 1008 specimens were evaluated: bile duct margin (279; 27.7%), gallbladder (203; 20.1%), liver lesions (125 cases; 12.4%), lymph nodes (147; 14.6%), pancreatic margin (120; 11.9%) and deposits (134; 13.3%). IFS were diagnosed as negative for malignancy (805; 79.9%), positive for dysplasia (8; 0.8%), suspicious for malignancy (6; 0.6%) and positive for malignancy (189; 18.8%). The overall diagnostic accuracy was 98.4%, and the discordant rate was 1.6%. The sensitivity, specificity, positive predictive value and negative predictive value were 94.7%, 99.4%, 97.5% and 98.6% respectively. The most important reason of discordant results was technical, followed by interpretational and sampling errors., Conclusion: The study demonstrates high diagnostic accuracy (98.4%) of IFS in a large dataset of HPB specimens. This comprehensive analysis apprises of the indications, errors and the impact of IFS diagnosis on subsequent HPB surgical management., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Skin tumors are common. Recommended treatment in most cases is surgery, with margins adapted. Except in the case of simple resection and suture, it is necessary to know the status of the margins before reconstructing the defect. A one-stage technique is possible with frozen section analysis, which gives the surgeon an intraoperative assessment of resection quality. The aim of our work is to study the reliability of the frozen section procedure., Method: A retrospective study included 689 patients who underwent surgery for skin tumor (excluding melanoma) between January 2011 and December 2019 at the University Hospital of Caen, France., Results: In 639 patients (92.75%), the frozen section analysis found healthy margins. There were 21 cases of discrepancy between the frozen section analysis and final histology. Infiltrating and scleroderma-like basal cell carcinomas showed a significantly higher frequency of affected margins on frozen section analysis (p < 0.001). The tumor size and location played a significant role in the margin status., Conclusion: In our department, the frozen section procedure is the reference examination indicating immediate flap reconstruction. The present study demonstrated its interest and overall reliability. However, it is to be used according to histologic type, size, and location., Competing Interests: Conflicts of interest None., (Copyright © 2023 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Stimulated Raman histology (SRH) is an ex vivo optical imaging method that enables microscopic examination of fresh tissue intraoperatively. The conventional intraoperative method uses frozen section analysis, which is labor and time intensive, introduces artifacts that limit diagnostic accuracy, and consumes tissue. SRH imaging allows rapid microscopic imaging of fresh tissue, avoids tissue loss, and enables remote telepathology review. This improves access to expert neuropathology consultation in both low- and high-resource practices. We clinically validated SRH by performing a blinded, retrospective two-arm telepathology study to clinically validate SRH for telepathology at our institution. Using surgical specimens from 47 subjects, we generated a data set composed of 47 SRH images and 47 matched whole slide images (WSIs) of formalin-fixed, paraffin-embedded tissue stained with hematoxylin and eosin, with associated intraoperative clinicoradiologic information and structured diagnostic questions. We compared diagnostic concordance between WSI and SRH-rendered diagnoses. Also, we compared the 1-year median turnaround time (TAT) of intraoperative conventional neuropathology frozen sections with prospectively rendered SRH-telepathology TAT. All SRH images were of sufficient quality for diagnostic review. A review of SRH images showed high accuracy in distinguishing glial from nonglial tumors (96.5% SRH vs 98% WSIs) and predicting final diagnosis (85.9% SRH vs 93.1% WSIs). SRH-based diagnosis and WSI-permanent section diagnosis had high concordance (κ = 0.76). The median TAT for prospectively SRH-rendered diagnosis was 3.7 minutes, approximately 10-fold shorter than the median frozen section TAT (31 minutes). The SRH-imaging procedure did not affect ancillary studies. SRH generates diagnostic virtual histologic images with accuracy comparable to conventional hematoxylin and eosin-based methods in a rapid manner. Our study represents the largest and most rigorous clinical validation of SRH to date. It supports the feasibility of implementing SRH as a rapid method for intraoperative diagnosis complementary to conventional pathology laboratory methods., (Copyright © 2023 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Objective: To assess a novel intraoperative core biopsy technique to provide enhanced guidance in partial glossectomies., Methods: All patients diagnosed with squamous cell carcinoma of the oral tongue were eligible for study participation. Following anesthesia, the planned resection and three points midway between the gross tumor and the intended ablation were marked. A core biopsy was performed with a needle spring on each point and sent for frozen sections. The initially planned resection was executed if the cores returned free of tumor. In case of a positive core biopsy, a new 1-1.5 cm margin was marked around that point. The main outcome measure was the closest final margin diameter, especially the deep ones. Other outcome measures were the core biopsies' sensitivity, specificity, and negative predictive value. Complications were recorded., Results: The final margins of 10 patients undergoing intraoperative core biopsies and 20 matched controls were analyzed. One patient had two positive cores and final negative margins after modifying the resection accordingly. Another patient had a positive biopsy diagnosed only on final pathology, and one close final margin. Patients that were operated with the new technique had larger margins compared to the controls: median (interquartile range) closest margin 5.95 (3.97; 9.63) mm versus 4 (2.25; 5) mm (p = 0.074) and median deep margin 8.6 (6.16; 10) mm versus 5 (3;10) mm (p = 0.411), respectively. There were no complications., Conclusion: A novel pre-resection intraoperative biopsy technique is presented. Core biopsies taken during glossectomies have the potential to prevent inadequate margins., Level of Evidence: 3 Laryngoscope, 133:2232-2236, 2023., (© 2022 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: When frozen pathological results of suspicious peritoneal nodules found in gastric cancer (GC) patients are negative or indeterminant, whether to perform gastrectomy will always be a dilemma for surgeons. This study aimed to facilitate intraoperative surgical decision-making based on frozen section (FS) results and clinicopathological characteristics., Methods: From January 2015 to July 2021, 318 GC patients were enrolled retrospectively. The correlations between frozen and paraffin pathology of peritoneal nodules were examined. Then, predictive factors of positive paraffin section (PS) results were identified, and a nomogram was constructed. The survival significance of gastrectomy was also explored., Results: Of 70 FS-negative patients, 59 (84.3%) had concordant negative PS results, while the PS results of 11 (15.7%) were positive. Forty-six (93.9%) and 3 (6.1%) of 49 patients with indeterminant FS results had positive and negative PS results, respectively. The PS results of 95 FS-positive patients were all positive. A nomogram for predicting positive PS results was developed based on Lauren type, nodule distribution, and CA125. Gastrectomy for FS-negative patients improved survival compared to no gastrectomy (HR 0.26, 95% CI 0.11-0.62; P = 0.0012). Survival benefits for gastrectomy vs. no gastrectomy were not demonstrated in patients with indeterminant (HR 0.74, 95% CI 0.27-2.01; P = 0.53) and positive (HR 0.87, 95% CI 0.43-1.74; P = 0.69) FS results., Conclusions: Gastrectomy can be justified for the treatment of operable GC patients with negative frozen pathological results of peritoneal nodules. For patients with positive and indeterminant frozen pathological results, gastrectomy is not recommended unless it is performed as palliative surgery., (© 2023. The Society for Surgery of the Alimentary Tract.)

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Despite the rapid developments in diagnostic techniques and medical sciences, pathologic diagnosis is still recognized as the gold standard for disease diagnose. Pathologic diagnosis is a time-consuming task performed for pathologists, needing profound professional knowledge and long-term accumulated diagnostic experience. Therefore, the development of automatic and precise histopathological image classification is essential for medical diagnosis. In this study, an improved VGG network was used to classify the breast cancer histopathological image from intraoperative rapid frozen sections. We adopt a transformed loss function by adding a penalty to cross-entropy in our training stage, which improved the accuracy on test data by 4.39%. Laplacian-4 was used for the enhancement of images, which contributes to the improvement of the accuracy. The accuracy of the proposed model on training data and test data reached 88.70% and 82.27%, respectively, which outperforms the original model by 9.39% of accuracy in test data. The process time was less than 0.25 s per image on average. Meanwhile, the heat maps of predictions were given to show the evidential regions in histopathological images, which could drive improvements in the accuracy, speed, and clinical value of pathological diagnoses. In addition to helping with the actual diagnosis, this technology may be a benefit to pathologists, surgeons, and patients. It might prove to be a helpful tool for pathologists in the future., (© 2023. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

Context.—: With the adoption of Epic/Beaker at our institution, surgical pathology specimens are assigned a Current Procedural Terminology (CPT) charge code at the time of accessioning, and pathologists have been made responsible for verifying the accuracy of the code before signing out the case., Objective.—: To determine with what frequency attending pathologists reassigned the correct charge code to a specimen when the code assigned at accessioning was incorrect, as well as to estimate the potential financial impact of missed changes., Design.—: We reviewed all specimens received for frozen section during a 7-month period, identified specimens where the default charge code that our departmental protocol assigns at frozen section (88305) was incorrect, and assessed the rate of successful code change by pathologists and the potential financial cost of each missed change., Results.—: Three hundred fifty-two of 2191 frozen section specimens (16%) required a change in the 88305 charge code. The codes for 195 specimens (55%) were correctly changed by the attending pathologist, while 157 (45%) were not changed (149) or were changed to an incorrect charge code (8). Individual pathologist change rates ranged from 0% to 100%, with a mean and median change rate of 43% and 24%, respectively. Using average code reimbursements at our institution, the loss in revenue from the 157 missed and incorrect frozen section changes was estimated at $13 788 ($1970 per month)., Conclusions.—: Pathologists showed highly variable rates of correcting CPT charge codes when the incorrect code had been previously assigned to a case, with associated loss of revenue from missed and incorrect code changes., (© 2023 College of American Pathologists.)

Study Objective: Describe the current practice patterns and diagnostic accuracy of frozen section (FS) pathology for children and adolescents with ovarian masses DESIGN: Prospective cohort study from 2018 to 2021 SETTING: Eleven children's hospitals PARTICIPANTS: Females age 6-21 years undergoing surgical management of an ovarian mass INTERVENTIONS: Obtaining intraoperative FS pathology MAIN OUTCOME MEASURE: Diagnostic accuracy of FS pathology RESULTS: Of 691 patients who underwent surgical management of an ovarian mass, FS was performed in 27 (3.9%), of which 9 (33.3%) had a final malignant pathology. Among FS patients, 12 of 27 (44.4%) underwent ovary-sparing surgery, and 15 of 27 (55.5%) underwent oophorectomy with or without other procedures. FS results were disparate from final pathology in 7 of 27 (25.9%) cases. FS had a sensitivity of 44.4% and specificity of 94.4% for identifying malignancy, with a c-statistic of 0.69. Malignant diagnoses missed on FS included serous borderline tumor (n = 1), mucinous borderline tumor (n = 2), mucinous carcinoma (n = 1), and immature teratoma (n = 1). FS did not guide intervention in 10 of 27 (37.0%) patients: 9 with benign FS underwent oophorectomy, and 1 with malignant FS did not undergo oophorectomy. Of the 9 patients who underwent oophorectomy with benign FS, 5 (55.6%) had benign and 4 (44.4%) had malignant final pathology., Conclusions: FSs are infrequently utilized for pediatric and adolescent ovarian masses and could be inaccurate for predicting malignancy and guiding operative decision-making. We recommend continued assessment and refinement of guidance before any standardization of use of FS to assist with intraoperative decision-making for surgical resection and staging in children and adolescents with ovarian masses., (Copyright © 2022. Published by Elsevier Inc.)

Background: Diagnosis and treatment of submandibular lesions is challenging. Carcinomas, which frequently occur, should be surgically removed with sufficient safety margins, while simultaneously protecting functional structures. In particular, the preservation of neuronal structures with simultaneous tumor control suggests that single-stage concepts are appropriate, although they are not yet established. The aim of this study was to evaluate intraoperative frozen section biopsy as a possible basis for a one-stage surgical concept to thus prevent functional alterations by reoperation., Methods: A total of 114 consecutive patients with neoplastic lesions in whom the type of lesion could not be determined after ENT examination and imaging were included in the study. Patients with a known history of carcinoma or evidence of an acute inflammatory or carcinogenic primary lesion in the ENT examination and/or imaging were excluded. An intraoperative frozen section biopsy was performed to determine the presence of a carcinoma. Patient-related data and the reliability of the frozen section result were recorded comparatively., Results: Intraoperative frozen section biopsy was performed in a total of 114 patients. Carcinomas were diagnosed with a sensitivity of 87% and a specificity of 100%. There would thus not have been unnecessary radical surgery in a one-stage approach. In 26 of 30 patients with carcinoma, a second operation could have been avoided., Conclusion: Intraoperative frozen section biopsy is potentially an important method to histologically confirm carcinomas and avoid two-stage procedures. The absence of false-positive findings would have prevented an unnecessary radical procedure in 100% of patients., (© 2022. The Author(s).)

Objective: To explore the feasibility and application value of intraoperative direct immunohistochemical (IHC) staining in improving the diagnosis accuracy in difficult cases of bronchiolar adenoma (BA). Methods: Nineteen cases with single or multiple pulmonary ground-glass nodules or solid nodules indicated by imaging in Cancer Hospital of Chinese Academy of Medical Sciences from January to July 2021 and with difficulty in differential diagnosis at frozen HE sections were selected. In the experimental group, direct IHC staining of cytokeratin 5/6 (CK5/6) and p63 was performed on frozen sections to assist the differentiation of BA from in situ/micro-invasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the control group, two pathologists performed routine frozen HE section diagnosis on these 19 cases. The diagnostic results of paraffin sections were used as the gold standard. The sensitivity and specificity of BA diagnosis, consistency with paraffin diagnosis and time used for frozen diagnosis were compared between the experimental group and the control group. Results: The basal cells of BA were highlighted by CK5/6 and p63 staining. There were no basal cells in the in situ/microinvasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the experimental group, the sensitivity and specificity with aid of direct IHC staining for BA were 100% and 86.7%, respectively, and the Kappa value of frozen and paraffin diagnosis was 0.732, and these were significantly higher than those in the control group ( P <0.05). The average time consumption in the experimental group (32.4 min) was only 7 min longer than that in the control group (25.4 min). Conclusions: Direct IHC staining can improve the accuracy of BA diagnosis intraoperatively and reduce the risk of misdiagnosis, but require significantly longer time. Thus frozen direct IHC staining should be restricted to cases with difficulty in differentiating benign from malignant diseases, especially when the surgical modalities differ based on the frozen diagnosis.

Background: Preoperative fine-needle aspiration (FNA) is widely used to differentiate malignant from benign thyroid nodules, while intraoperative frozen sections (FS) are suggested as a systematic supplement for intraoperative decision-making, but limitations still remain for both procedures., Methods: Medical records of 3807 patients with thyroid nodules who underwent both pathological diagnoses (FS and FNA) at our hospital were reviewed. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FNA and FS were also evaluated. We further designed an optimal integration scheme (FNA+selective FS) to predict thyroid nodule malignancy. Finally, the efficiency of the proposed integrated diagnostic model was validated using an independent external cohort., Results: For distinguishing malignant nodules, FNA had an accuracy of 90.3%, sensitivity of 90.7%, specificity of 85.2%, PPV of 98.8% and NPV of 40.4%. In contrast, the FS represented higher discriminative power (Accuracy, 94.5%; Sensitivity, 94.1%; Specificity, 100%; PPV, 100%; and NPV, 55.6%). we proposed the selective usage of FS (removed nodules with Bethesda category VI from routine FS, ~1/3 of total). The integrated new diagnostic model of FNA plus selective FS (FNA+sFS) achieved accuracy of 96.9%, sensitivity of 97.3%, specificity of 92%, PPV of 99.4%, and NPV of 71.6% (NRI=0.135, 95% CI 0.103-0.167, P <0.001) and was successfully applied to an external cohort (N=554)., Conclusion: Compared with the FNA diagnostic system, FS has an increased ability to distinguish benign and malignant thyroid nodules. The newly proposed integrated diagnostic model of FNA + selective FS can optimize the accuracy of diagnosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Mao, Ding, Wen, Zhang, Wu, You, Wu, Luo, Teng and Wang.)

Background: Intraoperative cytology (IC) is an alternative to frozen-section (FS) diagnosis. We present our experience with and the diagnostic value of IC during a 7-year period when FS was not available in a Peruvian Cancer Center., Material and Methods: This 7-year retrospective single-arm review study includes IC procedures performed by three pathologists between 2012 and 2018. These IC reports were reviewed independently by one pathologist and were correlated with the histologic diagnoses, which were used as the gold standard. All IC preparations (imprint, scrape, and crush smears) were stained with hematoxylin and eosin. IC interpretations were categorized as: malignant, benign, atypical, and "deferred to permanent sections." Sensitivity, specificity, and positive and negative predictive values were calculated by use of standard methods., Results: A total of 1814 IC cases prepared from various organs obtained from 887 patients were reviewed. Malignant, benign, atypical, and "deferred to permanent sections" IC diagnoses were 26.3%, 68.9%, 3.7%, and 1.9%, respectively. Atypical and deferred cases were excluded from the statistical analysis; thus 1712 cases were found to be eligible. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were 91.6%, 97.7%, 94.1%, 96.7%, and 96%, respectively., Conclusion: In experienced hands, IC is a rapid, cost-effective, and accurate alternative diagnostic modality for intraoperative diagnosis when FS is not available., (© 2022 Wiley Periodicals LLC.)

Background: The diagnostic performance of cytology was compared with the frozen results and its usability was evaluated as a rapid diagnosis method in intraoperative thoracic surgery in a single institution (Istanbul, Turkey)., Methods: All 197 subsequent patient specimens (cases) from 158 patients who were sent to our department from the thoracic surgery clinic for an intraoperative diagnosis request between the years 2016 and 2021 were evaluated. Obtained results from frozen and cytology were compared with final paraffin section diagnoses. Lesions were grouped into three different groups as nonneoplastic, benign, and malignant neoplasms., Results: Diagnostic accuracy values of cytology and frozen sections in intraoperative consultation were 98.8% and 99.4%, respectively. Sensitivity values of cytology and frozen sections in intraoperative consultation were 96.3% and 98.7%, respectively. Specificity values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Negative predictive values of cytology and frozen sections in intraoperative consultation were 96.7% and 98.9%, respectively. Positive predictive values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Kappa statistics between cytology and frozen revealed a very high interrater reliability (Cohen's Kappa value: 0.911; p = .001; p < .01). The difficulty in distinguishing primary and metastatic carcinoma, which is mostly undecided in frozen sections and the definitive diagnosis is left to paraffin sections, seems also be a problem in the cytological examination., Conclusions: Cytological diagnosis can be used in the evaluation of small biopsy specimens that require tissue preservation in intraoperative consultation, especially for immunohistochemical and advanced genetic studies., (© 2022 Wiley Periodicals LLC.)

Objectives: Monitoring of frozen section diagnostic performance provides an important quality improvement measure., Methods: Surgical specimens involving a frozen section diagnosis over a 3-year period were retrospectively reviewed. Glass slides were reviewed on cases with discordance. Discordance and deferral rates were calculated., Results: Of 3,675 frozen section diagnoses included, 96 (2.7%) were discordant with the final diagnosis. Additionally, 114 frozen section diagnoses (3.1%) were deferred. The organ-specific discordance rates were lowest in breast and genitourinary specimens and highest for pancreas, lymph node, and gynecologic specimens. Deferral rates were highest in musculoskeletal, breast, and hepatobiliary cases and lowest in thyroid, parathyroid, and neuropathology cases. Discordance was explained by block-sampling error (45%), specimen-sampling error (27%), or interpretation error (27%). Discordant frozen section diagnoses from gynecologic specimens were responsible for 81% of specimen-sampling errors; frozen section diagnoses of lymph nodes, head and neck, and pancreas were responsible for 54% of interpretation errors; 51% of block-sampling errors involved lymph node evaluation for metastatic carcinoma., Conclusions: Careful gross evaluation and microscopic examination of multiple levels should minimize specimen-sampling error and block-sampling error, respectively. Periodic review of accuracy and deferral rates may help reduce errors and improve the overall performance of this essential procedure., (© The Author(s) 2022. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Pathological consultation on intraoperative frozen sections plays a crucial role in the management of patients undergoing surgical therapy, and is also a key indicator for quality assurance in anatomical pathology. This study aimed to evaluate the diagnostic accuracy and technical quality of frozen sections in detecting hepatobiliary lesions with malignant potential., Patients and Methods: A retrospective database review was performed for 1208 cases intraoperative pathology consultation who underwent hepatobiliary lesions resection at our institution from 2016 to 2020. The intraoperative consultation cases during a 5-year period were reviewed and analyzed, including the measurement of the diagnostic accuracy and turnaround time of frozen sections, the reasons for discrepancies, and the rates of discordance and deferral., Results: In this study, we confirmed that the overall accuracy, sensitivity and specificity were 95.3 %, 96.3 % and 96.6 %, respectively, in distinguishing benign from malignant lesions. The rates of deferred and discordant diagnoses were 2.57 % and 2.2 %, respectively. The overall frozen section turnaround time was 22.1 min. The most common cause of deferred and discordant was poor section quality, the lesion of bile duct margin on the frozen section, misinterpretation of difficult and complicated cases, etc. CONCLUSIONS: This study confirms that the intraoperative frozen sections can serve as a rapid, accurate and robust method for the pathological diagnosis of suspected hepatobiliary lesions. However, it should be noted that some poor technical problems, pathological assessment of tumor margin and difficult cases are the most frequently causes of deferred and discordant interpretations., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: To determine outcomes following relocation of frozen section services (FSS) and the implementation of a dedicated gastrointestinal frozen service., Methods: We reviewed our FSS 6 months prior to and following FSS relocation. Satisfaction surveys were sent to surgeons and pathologists. Survey feedback resulted in a pilot of gastrointestinal subspecialist frozen section coverage., Results: There were 1,607 and 1,472 specimens from 667 and 602 patients pre- and post-FSS relocation, respectively. There was a decline in median specimen delivery time to pathology (12 vs 10 minutes, P < .001) and an increase in median time from receipt in pathology to intraoperative diagnosis (20 vs 22 minutes, P = .008) in cases with intrapathology consultation but no change without consultation (median, 19 minutes). Intrapathology consultation decreased from 19.7% (317/1,607) to 11.5% (169/1,472) (P < .001). Discordance rates between frozen section and permanent section remained low and similar (2.0% [33/1,607] vs 2.7% [40/1,472], P = .24). There was no significant change in discordance with dedicated gastrointestinal subspecialty frozen section interpretation., Conclusions: Relocation of FSS and dedicated subspecialty interpretation may improve surgeon satisfaction but can also create workflow challenges. Pathology departments need to achieve a balance between satisfaction and adequacy to establish best frozen section coverage models., (© The Author(s) 2022. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Importance: Methods of assessing final margin status in patients undergoing surgery for oral cavity squamous cell carcinoma, such as intraoperative frozen section histopathology (IFSH) taken from the tumor bed, may have limitations in accuracy., Objective: To evaluate the accuracy and implications of using IFSH samples to assess tumor bed margins in patients undergoing surgery for oral cavity squamous cell carcinoma (SCC)., Design, Setting, and Participants: This cross-sectional study included 1257 patients who underwent surgery for oral cavity SCC between January 1, 2000, and December 31, 2015, at an academic cancer center. A total of 4821 IFSH samples were examined from 1104 patients (87.8%) who had at least 1 IFSH sample. Institutional practice is to harvest margins for IFSH from the tumor bed. Statistical analysis was performed from August 1, 2021, to April 4, 2022., Main Outcomes and Measures: Sensitivity and specificity were calculated for IFSH samples of margins compared with the permanent pathology samples of the same tissue and for IFSH compared with the final tumor specimen histopathology (FTSH). Results were classified using a binary method, with histopathologic reports interpreted as either negative (including negative or atypia or dysplasia) or positive (including carcinoma in situ, suspicious, or positive)., Results: A total of 1257 patients met the inclusion criteria, including 709 men (56.4%), with a median age of 62 years (IQR, 52-73 years); 1104 patients (627 men [56.8%]; median age, 62 years [IQR, 52-72 years]) had IFHS samples. For IFSH relative to permanent sections of the IFSH tissue, sensitivity and specificity of IFSH were high (sensitivity, 76.5% [95% CI, 67.5%-85.5%]; specificity, 99.9% [95% CI, 99.8%-100%]), with discordant results in 24 of 4821 total specimens (0.5%). Final specimen margins were positive in 11.7% of patients (147 of 1257). Compared with FTSH, the sensitivity of IFSH for defining margin status was 10.8% (95% CI, 5.8%-15.8%), and the specificity was 99.1% (95% CI, 98.8%-99.4%). The rate of discordance was 4.0% (171 of 4284 specimens) between IFSH and FTSH., Conclusions and Relevance: The findings of this cross-sectional study suggest that IFSH is accurate compared with permanent pathologic characteristics of the same tissue, but less reliable at assessing final margin status on the tumor specimen. Despite a high specificity, the sensitivity of IFSH compared with FTSH is low, which may be associated with the inherent inability of tumor bed IFSH margin analysis to accurately account for the 3-dimensional association of tumor margins with the periphery of the specimen and the overall low rate of positive final tumor margins. Although tumor bed IFSH is widely used in the management of oral cavity cancer, this study suggests that there are limitations of this modality in assessing the final surgical margin status.

Background/aim: An accurate evaluation of resection margin (RM) is critical in breast-conserving surgery (BCS) as negative RM status is critical for successful local control. We compared gross and microscopic methods for RM evaluation and analyzed their concordances., Patients and Methods: Gross evaluation (GE), frozen section analysis (FSA), and permanent section diagnosis (PSD) were compared for specimens from 725 breast cancer patients., Results: The RM was grossly involved in 74 cases (10.2%). The sensitivity and specificity of GE were 22.9% and 96.1%, respectively. FSA revealed positive RM in 290 cases (40.0%), with high sensitivity (86.7%) and specificity (83.1%). With PSD, 240 cases (33.1%) showed RM involvement. Discordant results between gross and microscopic methods were observed in 104 cases (14.3%)., Conclusion: Our observations of the low sensitivity of GE, high discordance rate between gross and microscopic methods, and high sensitivity and specificity of FSA support the necessity of intraoperative FSA for assessing RM status during BCS., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: This study aimed to compare the intraoperative frozen section with the surgical margin in the postoperative surgical margins of the postoperative pathology of oral squamous cell carcinomas in order to examine the reliability of the frozen section., Methods: A retrospective analysis was conducted for patients who underwent surgery for oral squamous cell carcinoma in a tertiary hospital between January 2018 and 2019. The intraoperative frozen section examinations, grade of the tumor, number of lymph nodes, number of affected lymph nodes, depth of invasion, perineural invasion, lymphovascular invasion, and extranodal extension were recorded from the pathological records. The concordance between the frozen section examination and postoperative pathology 2 methods was examined using the Cronbach α coefficient. Sensitivity, specificity, positive predictive value, negative predictive value regarding surgical margins, and accuracy were calculated and reported., Results: Overall, 181patients who underwent surgery for oral cavity cancers were included; 118 (65.2%) were males. The mean (± standard deviation) age of the included participants was 57.4 ± 16.1 years. The most common tumour subsite was the tongue (n = 71, 39.2%). There was concordancy between the frozen, positive intraoperative malignancy and the postoperative pathology malignancy. The frozen, negative intraoperative malignancy and postoperative safe surgical margin did not significantly differ., Conclusion: As a result of intraoperative frozen examination, we found conformity between the postoperative pathology results of patients with positive and negative surgical margins. Frozen section examination could be used safely to examine intraoperative surgical margins of oral squamous cell carcinoma.

Background: In 2021, there is an increased global trend for sending sentinel lymph node biopsy (SLNB) specimens for permanent section (PS) without intraoperative frozen sections (FS). This pilot study conducted in Thailand determines the re-operation rate for SLNB without FS., Method: We retrospectively reviewed 239 SLNB cases without FS at King Chulalongkorn Memorial Hospital from April 2016 to April 2021. The patients were diagnosed with primary invasive breast cancer with clinically negative nodes. The clinical nodal status was assessed from physical examination. The re-operation rate was determined by the number of positive SLNs; where 3 more nodal metastases were subjected to a second surgical procedure., Result: Between April 2016 and April 2021, 239 patients who had undergone SLNB in accordance with ACOSOG Z0011 criteria with PS alone was enrolled. A total of 975 SLNs were removed from these 239 patients, with an average of 4.15 nodes per patient. Out of 239 patients, 21 (8.8%) and 6 (2.5%) had metastatic disease in 1 and 2 nodes, respectively. The remaining 212 (88.7%) patients had no nodal metastasis. None of the patients were subjected to a second surgical procedure., Conclusion: We conclude that the implementation of SLNB with PS analysis alone in patients who satisfy the ACOSOG Z0011 criteria, with a re-operation rate of 0%, does not have outcomes that would be altered by the standard of care additional FS analysis. With ommision of FS analysis, operation cost, operative time and anesthetic side effects are projected to decrease., (© 2022. The Author(s).)

Ovarian cancer is the seventh most common form of cancer among women worldwide. The aim of the study was to determine the accuracy of a frozen section and the factors affecting the accuracy of frozen diagnosis of ovarian neoplasms. This retrospective, cross-sectional study was conducted on 401 patients with ovarian masses with frozen section diagnosis in Shahid Faghihi Hospital affiliated to Shiraz University of Medical Sciences between 2014 and 2018. Each ovarian tumor sample was evaluated for histopathologic diagnosis using frozen and paraffin-embedded sections, which were reviewed by an expert gynecologic pathologist. Accuracy and diagnostic values were estimated by comparing the results of the 2 techniques, using the paraffin section as the gold standard. The overall accuracy of the frozen section was 94.5%. Its sensitivity was 85.3% for malignant, 88.2% for borderline, and 99.6% for benign tumors. Its specificity was also 99.7% for malignant, 98.0% for borderline, and 90.9% for benign tumors. The positive predictive value was 98.9% for malignant, 86.5% for borderline, and 94.6% for benign tumors. Most false negatives occurred in mucinous and borderline tumors. The sensitivity of malignant tumors of germ cell and sex cord-stromal cell types were 64.3% and 95.5%, respectively. The specificity of germ cell and sex-cord stromal tumors were 100% and 93.8%, respectively. Frozen section seems to be a precise technique for histopathologic diagnosis of ovarian tumors. However, borderline and mucinous tumors are the most problematic issues during frozen section diagnosis and malignant germ cell tumors have the lowest sensitivity., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 by the International Society of Gynecological Pathologists.)

Background: Ovarian Cancer (OC) constitute the eighth most common cancers among women worldwide. Surgery remains the cornerstone in the management of OC. Intraoperative frozen section (FS) diagnosis is widely used to decide the surgery course. We aimed to assess the reliability of intraoperative FS diagnosis for treatment planning of patients with suspected OC from a multidisciplinary perspective. The clinical consequences of reclassification and the multidisciplinary management of the therapy plan, is the secondary aim of this study. To our knowledge, this information is sparely investigated., Methods: A single-center, retrospective population-based study of patients who underwent surgery for suspected OC between 2018 and 2020. Histopathological outcomes were classified as benign, borderline, or malignant. The FS diagnosis was the diagnostic test, and the final histopathology report was the gold standard. Diagnostic capability for treatment planning was assessed, and modifications made possible by overall clinical knowledge were discussed., Results: A total of 358 patients were identified, of whom 187 were included in the FS group. Overall accuracy was 89.8%, and 19 patients were reclassified; the malignancy grade of 15 tumors was underestimated. Prevalence, sensitivity, specificity, positive predictive value, and negative predictive value for invasive malignancies on FS were 54.0% (CI 46.6-61.3%), 88.1% (CI 80.2-93.7%), 98.8% (CI 93.7-99.9%), 98.9% (CI 92.7-99.8%), and 87.6% (CI 80.6-92.4%), respectively. Tumors incorrectly graded by FS tended to be of borderline-related., Conclusions: The reliability of the FS methodology was an accurate test to help perform appropriate surgery and plan swift oncological treatment. FS is a reliable method to diagnose invasive malignancies and benign pathology. The communication between the pathologist, surgeon, and medical oncologist is highly important for both intraoperative decision-making and postoperative patient care.

Context.—: Intraoperative consultation-frozen section diagnosis (FSD)-determines tumor pathology and guides the optimal surgical management of ovarian neoplasms intraoperatively., Objective.—: To evaluate the diagnostic accuracy of the FSD and analyze the discrepancy between the FSD and final diagnosis., Design.—: This is a retrospective study of 618 ovarian neoplasm FSDs from 2009 to 2018 at a tertiary health care center. The discrepant cases were reviewed and reevaluated by gynecologic and general surgical pathologists. The outcomes of interest were performing unnecessary procedure, returning for a second surgery, and 30-day postoperative mortality., Results.—: The sensitivity and the positive predictive value of the FSD were lower in borderline tumors than in benign and malignant epithelial ovarian tumors. Major and minor discrepancies were identified in 5.3% (33 of 618) and 12.3% of (76 of 618) cases, respectively. A root cause analysis of the major discrepant cases showed that sampling error accounted for 43% (14 of 33). The discrepancy distributions of gynecologic and general surgical pathologists were statistically similar in the overall cohort (P = .65). The overall κ for diagnostic agreement among gynecologic pathologists, general surgical pathologists, and final diagnosis was 0.18 (0.10-0.26, P < .001), implying only a slight overall agreement. Of the major discrepant cases, only 3 had a clinical implication. One overdiagnosed patient underwent an unecessary procedure, and 2 underdiagnosed patients were recommended to return for a second surgery. No patient had 30-day postoperative mortality., Conclusions.—: Frozen section diagnosis remains a definitive diagnostic tool in ovarian neoplasms and plays a crucial role in guiding intraoperative surgical management.

Objectives: The lung is a major target organ of metastasis in several cancers. To distinguish primary lung cancer from pulmonary metastases is a clinical challenge. Small pulmonary nodules (PNs) are frequently diagnosed by frozen section diagnosis (FSD) intraoperatively after resection. Intraoperative FSD is very important to determine the extent of subsequent surgical procedures. This study aimed to know the validity of surgical decision based on FSD for preoperatively unconfirmed PN with previous malignancy., Methods: We retrospectively evaluated 96 patients with suspected malignant PN who underwent intraoperative FSD between 2018 and 2020. Intraoperative FSD, final diagnosis, and surgical procedure data were examined., Results: Surgical procedure adequacy, based on FSD for preoperatively unconfirmed PN with previous malignancy, was 91% (88/96). The overall diagnostic accuracy of FSD was 83.3% (80/96). Discrepancy was noted in two cases (2.1%), and conclusive diagnosis could not be reached intraoperatively in 14 cases (14.6%). A second surgery was required in three patients and no additional excision for primary lung cancer was performed in three patients. Conversely, there were three cases of over-surgery, namely, lobectomy for pulmonary metastasis., Conclusions: Surgical decision-making based on FSD for preoperatively unconfirmed PN in patients with previous malignancy was generally adequate. However, there were inadequate or excessive surgical procedures due to limitations in the accuracy of intraoperative FSD. Improving the accuracy of intraoperative FSD is a necessary step for obtaining adequate surgical decision-making and precision medicine., (© 2022. The Author(s), under exclusive licence to The Japanese Association for Thoracic Surgery.)

The intent of this brief communication is to describe a unique incomplete staining frozen section pathology artifact encountered during Mohs Micrographic Surgery. At the authors&rsquo; institution, an amorphous, eosinophilic artifact that obscured cellular architecture was observed multiple times during histological interpretation. It was determined that incomplete tissue staining was likely caused by weak staining, possibly related to an interaction between hematoxylin dye solution and acetone. We adjusted our SLS stain line protocol by adding a 15 second water rinse between the acetone and hematoxylin pots and then compared the old fixation protocol with our new fixation protocol. This artifact, which was regularly found intraoperatively at five separate MMS laboratories has sustainably resolved. Mohs Micrographic Surgery (MMS) is a dermatologic procedure that includes tumor extirpation, tissue grossing, slide preparation, and microscopic histologic interpretation. Tissue grossing and slide preparation are vital components of the MMS procedure. There are many steps throughout tissue processing that can result in frozen section pathology artifacts. Frequently encountered frozen section pathology artifacts include vacuolation of cytoplasm or &ldquo;freeze artifact,&rdquo; overstaining and understaining with hematoxylin and eosin, incomplete dehydration, and splaying of collagen in the dermis.1-3 We describe a unique incomplete staining frozen section pathology artifact. J Drugs Dermatol. 2022;21(5):542-544. doi:10.36849/JDD.6722.

Photo-isolation chemistry (PIC) enables isolation of transcriptome information from locally defined areas by photo-irradiation. Here, we present an optimized PIC protocol for formalin-fixed frozen and paraffin mouse sections and fresh-frozen mouse sections. We describe tissue section preparation and permeabilization, followed by in situ reverse transcription using photo-caged primers. We then detail immunostaining and UV-mediated uncaging to the target areas, followed by linear amplification of uncaged cDNAs, library preparation, and quantification. This protocol can be applied to various animal tissue types. For complete details on the use and execution of this protocol, please refer to Honda et al. (2021)., Competing Interests: S.O. and Y.O. are involved in a pending patent related to PIC technology (application number, 2019-094216; patent office, Japan Patent Office; current status, patent pending). All the other authors declare no competing interests., (© 2022 The Author(s).)

Objective: A primary medical relevance of thyroid nodules consists of excluding thyroid cancer, present in approximately 5% of all thyroid nodules. Fine-needle aspiration biopsy (FNAB) has a paramount role in distinguishing benign from malignant thyroid nodules due to its availability and diagnostic performance. Nevertheless, intraoperative frozen section (iFS) is still advocated as a valuable tool for surgery planning, especially for indeterminate nodules., Methods: To compare the FNAB and iFS performances in thyroid cancer diagnosis among nodules in Bethesda Categories (BC) I to VI. The performance of FNAB and iFS tests were calculated using final histopathology results as the gold standard., Results: In total, 316 patients were included in the analysis. Both FNAB and iFS data were available for 272 patients (86.1%). The overall malignancy rate was 30.4%% (n = 96). The FNAB sensitivity, specificity, and accuracy for benign (BC II) and malignant (BC V and VI) were 89.5%, 97.1%, and 94.1%, respectively. For all nodules evaluated, the iFS sensitivity, specificity, and accuracy were 80.9%, 100%, and 94.9%, respectively. For indeterminate nodules and follicular lesions (BC III and IV), the iFS sensitivity, specificity, and accuracy were 25%, 100%, and 88.7%, respectively. For BC I nodules, iFS had 95.2% of accuracy., Conclusion: Our results do not support routine iFS for indeterminate nodules or follicular neoplasms (BC III and IV) due to its low sensitivity. In these categories, iFS is not sufficiently accurate to guide the intraoperative management of thyroidectomies. iFS for BC I nodules could be an option and should be specifically investigated.

Background: Pediatric central nervous system (CNS) tumors have a different histological spectrum as compared to adults with the infantile group having even more varied and distinct histological profiles. Intra-operative diagnosis is especially important as it guides the neurosurgeon to tailor an approach which is best suited for a particular case. The aim of the study was to evaluate the diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value of frozen section (FS) and squash cytology and to find out the degree of correlation (kappa value) between the two procedures., Materials and Methods: A prospective study was conducted on 55 pediatric patients with clinicoradiologically diagnosed CNS lesions for a period of 2.5 years. Intra-operative squash smears and FS were made and stained with hematoxylin and eosin stain. Diagnosis made subsequently on paraffin embedded sections was taken as the gold standard., Results: Although the specificity (90%) and positive predictive value (96%) were comparable between the two procedures, sensitivity (91.4%) and negative predictive value (75%) of FS was more as compared to squash cytology. Both the diagnostic modalities showed substantial agreement (k = 0.728)., Conclusion: Even though the histological spectrum of pediatric CNS tumors is more varied than adults, FS gives a reasonable intra-operative diagnosis and better results when compared to squash alone., Competing Interests: None

Background: Breast cancer is one of the most prevalent malignancies in women worldwide, and the rate of breast cancer is increasing among Iranian women. The purpose of this study is to determine the cost-effectiveness of intraoperative frozen section analysis in women with breast cancer., Methods: This study was a cost-effectiveness analysis, which was implemented as a cross-sectional study from a societal perspective. In this case, total direct and indirect costs were calculated, and the study outcome was involved in preventing reoperation. A data collection form has been used to collect the cost and effectiveness data. The sample size was comprised of all the patients referred to the hospitals of Shiraz University of Medical Sciences for breast cancer surgery in 2019. The patients were studied in two different groups, including individuals who received frozen counseling during surgery, and individuals who did not receive it. A one-way sensitivity analysis was performed for this case. Moreover, the Tree Age and Microsoft Excel Software were employed for analyzing processes., Results: The results demonstrated that the mean costs of frozen and non-frozen patients were 4168$ and 3843$ purchasing power parity (PPP), respectively. In addition, the effectivenesses were 0.996 for the former and 0.8 for the latter. Furthermore, the incremental cost-effectiveness ratio (ICER) was 1658.2 PPP$. This issue revealed that the frozen section procedure during surgery was more cost-effective than the other case. Because, the cost-effectiveness of this option was below the threshold. Besides, the one-way sensitivity analysis confirmed the robustness of the study results., Conclusion: The results showed that performing frozen sections during surgery in women with breast cancer was more cost-effective than ignoring them. Indeed, the frozen section can prevent the costs of subsequent reoperations., (Copyright: © Iranian Journal of Medical Sciences.)

Intraoperative frozen sections of specimens taken during thoracic surgery are widely seen as the gold standard. However, the accuracy of intraoperative cytology remains contentious. The study aims to estimate the value of intraoperative cytology by analyzing feasibility, accuracy, time requirements, and possible limitations when compared to standard frozen sections. To this end, we examined a total of 532 intraoperatively harvested specimens out of the 518 resected thoracic tumors from 360 patients between August 2016 and August 2017. The specimens were subject to intraoperative rapid cytology that was later counter compared to the final histology results. The mean time between the intraoperative harvesting and arrival at the laboratory was 2.23 min, and it took a further 3.5 min until the results were communicated to the surgeon. Cytologically, 218 cases (41%) were classified as malignant, 291 (55%) as benign, and 23 (4%) remained unclear. In 55 malignant cases, we observed additional benign formations. The final histological examination performed later yielded 267 malignant and 265 benign cases. Therefore, the sensitivity and specificity of rapid intraoperative cytology were 82% and 99%, respectively, with a negative/positive predictive value of 86%/99%. We conclude that the intraoperative rapid cytology is a fast, accurate, sensitive, and specific procedure for intraoperative decision making and is a distinctly helpful alternative or adjunct for the thoracic surgeon, providing that one is aware of the plausible limitations of this technique., (© 2021. The Author(s), under exclusive license to Springer Nature Switzerland AG.)