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Giant congenital melanocytic nevi (GCMN) are rare benign congenital melanocytic proliferations. Malignant transformation of these lesions is even rarer. This case report might be the first to describe the cytomorphological features of amelanotic melanoma of the lumbosacral region arising from GCMN in infancy, diagnosed by fine needle aspiration, highlighting the diagnostic challenges and technical difficulties encountered. [ABSTRACT FROM AUTHOR]

Background: The reported risk of malignancies (ROM) remains controversial for fine needle aspiration (FNA) of thyroid nodules in the African American (AA) population. Herein, the ROM along with frequency was assessed for each of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) diagnostic categories. Materials and Methods: The electronic pathology archive of a large academic hospital was retrospectively searched for cytopathology reports of thyroid nodules in AA patients (2010–2019) and Non‐African American (NAA) control cases. The patients' demographic, thyroid nodule characteristics, FNA results using TBSRTC and surgical diagnoses were recorded, whenever available. Results: Three hundred ninety‐one cases were identified, 317 females (81.1%) and 74 males (18.9%) with median age 50.0 (SD = 14.4). The mean size of the nodules was 2.1 cm (SD = 1.4). The Bethesda categories were: 5.4% (I), 35.0% (II), 35.3% (III), 7.7% (IV), 3.3% (V) and 13.3% (VI). The overall ROM of thyroid nodules was 43.8% (89/203) on surgical follow‐up (203/391). The ROM in each Bethesda categories were: 33.3% (I), 11.6% (II), 35.2% (III), 15.8% (IV), 83.3% (V) and 100% (VI) on surgical follow‐up. The frequency of thyroid nodules was higher in AA females; however, the ROM was higher in AA males (48.3%) compared with AA females (41.2%). Conclusion: The ROM in Categories I, II and III was higher than those reported in the TBSRTC while being similar in Categories IV, V and VI. The overall risk of thyroid malignancy in our AA patient population was higher than those in the literature. The overall ROM of thyroid nodules in AA males was higher than of AA females. [ABSTRACT FROM AUTHOR]

Objective: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine neoplasm that predominantly affects elderly and immunocompromised patients. Merkel cell polyoma virus (MCPyV) is clonally integrated into the majority of MCCs and has been linked to patient outcomes, playing a central role in the pathogenesis of the disease. We aimed to assess the utility of MCPyV immunohistochemistry (IHC) in the diagnosis of MCC in cytology cell block specimens and correlating with clinicopathologic features. Methods: Fifty‐three cytology samples of MCC with sufficient cell block material were stained for MCPyV by IHC and scored semi‐quantitatively in extent and intensity. Morphologic mimics of MCC including small cell lung carcinoma (n = 10), non‐Hodgkin lymphoma (n = 10), basaloid squamous cell carcinoma (n = 6) and other neuroendocrine carcinomas (n = 8) were stained in parallel. Positive staining was defined as >1% of the tumour cells showing at least moderate staining intensity. Results: The cytologic features of MCC were characterized by high nuclear‐cytoplasmic ratios, hyperchromatic nuclei with 'salt and pepper' chromatin, and nuclear moulding. MCPyV was detected in 24 of 53 cases (45%). Staining was strong and diffuse in roughly half of the positive samples. Of the morphologic mimics, one follicular lymphoma showed strong and diffuse staining. In contrast to prior studies, we saw no association between MCPyV status and patient outcomes. Conclusion: Merkel cell polyoma virus IHC is highly specific (97%) for the diagnosis of MCC in our cohort, and can serve as a useful diagnostic tool for distinguishing MCC for morphologic mimics. [ABSTRACT FROM AUTHOR]

Background: Recognizing the parathyroid gland and distinguishing the parathyroid from thyroid lesions in fine needle aspiration (FNA) is challenging. This study aimed to identify cytomorphologic features suggestive of parathyroid origin and to assess the utility of cytopathology in conjunction with ancillary tests in the identification of parathyroid glands. Materials and methods: Ultrasound (US) guided FNA of parathyroid gland and lesions in 81 patients were reviewed concerning clinical history and correlated to histopathologic findings in available cases. FNA smears were evaluated for cellularity, architectural patterns, cellular and nuclear features, and background of the smears. In 78 cases, FNA was supplemented by a measurement of parathormone (PTH) levels in the needle washout fluid (FNA‐PTH assay) and/or GATA3/PTH/chromogranin‐A immunostainings. Results: Sixty‐four cases were diagnosed cytologically as parathyroid lesions in conjunction with FNA‐PTH assay and/or immunocytochemical examinations. In an additional nine cases, a diagnosis of parathyroid lesions was rendered after repeated FNA with FNA‐PTH assay. The histolopathologic diagnosis of surgically excised cases (n = 75) included parathyroid adenoma (60 cases), atypical parathyroid adenoma (4 cases), parathyroid hyperplasia (10 cases), and parathyroid carcinoma (1 case). Major cytological findings of parathyroid tissue included high cellularity, scattered naked nuclei, cribriform and three‐dimensional clusters, stippled chromatin, and oxyphilic cytoplasm while papillary pattern or colloid‐like material was identified in three cases respectively. No nuclear grooves or inclusions were seen in any case. Conclusions: High cellularity scattered naked nuclei, cribriform and three‐dimensional patterns, stippled chromatin and oxyphilic cytoplasm are cytomorphologic features that favour parathyroid origin. A combination of these features with FNA‐PTH assay and/or GATA3, PTH, and chromogranin‐A immunostainings on cytologic specimens aid in the identification of parathyroid glands and the distinguishing of parathyroid from thyroid lesions. [ABSTRACT FROM AUTHOR]

Immunotherapy has become a promising cancer treatment in the past decade, and IHC is the most commonly used testing method for PDL‐1/PD1 evaluation. In general, PD‐L1 assays can be performed on both FFPE specimens and cytological samples. However, their use on smears is not yet well‐established or validated. Nowadays, digital images and advanced algorithms can aid in interpreting PD‐L1 in cytological samples. Understanding the immune environment of non‐small cell lung cancer (NSCLC) is critical in developing successful anticancer immunotherapies. The use of a multiplexed immunofluorescence (mIF) assay on cytological samples obtained through minimally invasive methods appears to be a viable option for investigating the immune environment of NSCLC. This review aims to briefly summarize the knowledge of the role of cytopathology in the analysis of PD‐L1 by immunocytochemistry (ICC) and future directions of cytopathology in the immunotherapy setting. [ABSTRACT FROM AUTHOR]

This article discusses the cytology of a parietal swelling in a 52-year-old man. The patient presented with a scalp mass that had been enlarging over the past 6 weeks. Fine needle aspiration (FNA) and core needle biopsy (CNB) were performed, and the pathological report revealed a giant cell lesion of the skull. The patient also exhibited high blood pressure, renal insufficiency, and hypercalcemia. A computed tomography scan revealed a soft tissue mass with destruction of the parietal bone. The article emphasizes the challenges in diagnosing brown tumours through FNA due to overlapping features with other giant cell lesions. Clinical information, imaging, and laboratory tests are crucial for an accurate diagnosis. [Extracted from the article]

Objective: The cytomorphological features of parathyroid tissue (PTT) may overlap with those of thyroid lesions, thus posing a diagnostic challenge. In this retrospective study, we reviewed our institutional experience in using parathyroid hormone (PTH) immunocytochemistry (ICC) to substantiate the diagnosis of PTT on fine needle aspiration (FNA). Methods: Our pathology database was searched for FNA cases in which PTH ICC was performed between 1 January 2015 and 31 March 2022. PTH ICC was performed on a ThinPrep slide in cases with a clinical suspicion of PTT or with cytomorphological features raising the possibility of PTT. Patients' clinicopathological characteristics, PTH ICC results, cytological diagnoses, and surgical follow‐ups, if available, were reviewed and analysed. Results: The study cohort included 103 cases clinically designated as thyroid (n = 85, 82.5%), parathyroid (n = 11, 10.7%) and neck soft tissue (n = 7, 6.8%). PTH immunostaining was negative, positive, and indeterminate in 53 (51.5%), 27 (26.2%), and 23 (22.3%) cases, respectively. Surgical follow‐up was available in 27 (26.2%) cases, including 17 thyroid lesions and 10 PTT cases. All positive PTH cases were confirmed to be PTT, while all but one of the negative PTH cases were non‐PTT on follow‐up. The calculated sensitivity, specificity, positive and negative predictive values were 85.7%, 100%, 100% and 93.3%, respectively. Conclusion: Our study demonstrates that PTH ICC performed on additional ThinPrep slides is a valuable adjunct test in FNA samples with a differential diagnosis of PTT vs non‐PTT. Low cellularity may be a limiting factor in the accurate assessment of PTH by ICC. [ABSTRACT FROM AUTHOR]

Background: Bone fine needle aspiration (FNA) presents several diagnostic challenges including limited sample material, reduced ability to assess the architecture, and lack of a standardised reporting system. The aim of our study is to present our experience regarding bone FNA. Methods: We performed a 6‐year retrospective search of our archives to identify all FNA cases of bone lesions. Available data regarding patients' demographics, cytopathology, and surgical pathology were recorded. The FNA cases were then grouped into five categories (atypical, neoplasm‐benign, neoplasm of unknown malignant potential, suspicious for malignancy, and malignant) and the risk of malignancy (ROM) was calculated. Results: A total of 341 FNA cases performed in 337 patients (M = 173, F = 164; mean age = 57.2 years) were identified. The iliac crest was the most commonly biopsied site (n = 134). The adequacy of bone FNA was 77.4%. The sensitivity and specificity regarding the nature of the lesion were 96.5% and 100%, respectively. The overall diagnostic accuracy of bone FNA was 77%. The accuracy of bone FNA for non‐metastatic bone lesions including non‐neoplastic lesions was 74%, while the diagnostic accuracy of bone FNA for a metastatic disease was 83.5%. The diagnostic accuracy for primary neoplastic lesions was 70%. The frequency (n,%) of cytomorphological categories were as follows: atypical (30, 8.8%); neoplasm‐benign (6, 1.8%); neoplasm of unknown malignant potential (18, 5.3%); suspicious for malignancy (4, 1.2%); and malignant (145, 42.5%). The ROM in these categories was respectively as follows: 51.7%, 0%, 46.7%, 100%, and 99.1%. Conclusion: FNA is a sensitive and specific technique for the diagnosis of bone lesions. In most instances, an accurate diagnosis can be achieved if adequate material, ancillary studies, and radiological correlation are available. [ABSTRACT FROM AUTHOR]

Introduction: Pleomorphic dermal sarcoma (PDS) is an uncommon cutaneous mesenchymal neoplasm. It is cytomorphologically identical to atypical fibroxanthoma (AFX), but differs due to its invasion beyond the dermis. We undertook an examination of our experience with fine needle aspiration (FNA) biopsy cytology of PDS. Materials and Methods: Our cytopathology files were searched for examples of PDS with concomitant histopathological verification. FNA biopsy smears and cell collection were performed using standard techniques. Results: Seven cases of PDS were retrieved from four different patients (M:F, 1:1; age range: 63–88 years; mean age = 78 years). All patients (57%) presented with a primary tumour with one having an FNA biopsy of two local recurrences and a single distant metastasis. Five aspirates were from the extremities and two from the head/neck. Tumours ranged from 1.0 to 3.5 cm (mean, 2.2 cm). Specific cytological diagnoses were pleomorphic spindle/epithelioid sarcoma (3 cases), PDS (2), AFX (1), and atypical myofibroblastic lesion, query nodular fasciitis (1). Immunohistochemical (IHC) staining from FNA‐generated cell blocks in two cases showed non‐specific staining with vimentin in both cases; positive CD10, CD68, and INI‐1 staining in one case; and smooth muscle actin expression in the other. Multiple negative stains were performed in both of these cases to exclude malignant melanoma, carcinoma, and specific forms of sarcoma. Cytopathology consisted of a mixture of spindle, epithelioid, and bizarre pleomorphic cells. Conclusion: Coupled with ancillary IHC stains, FNA biopsy can help recognise PDS as a sarcomatous cutaneous neoplasm, but is unable to distinguish PDS from AFX. [ABSTRACT FROM AUTHOR]

Chordoma is a rare primary central nervous system tumour of notochordal origin. Proper intraoperative or preoperative diagnosis of this entity is crucial for appropriate surgical management. The most common histopathological subtype is conventional chordoma. Cytological characteristics of this subtype are quite distinctive and the diagnosis can be easily made by cytology. There are two particularly important features that are observed in both squash smear and fine needle aspiration specimens: an abundant myxochondroid stroma and cells with large vacuoles, including physaliferous cells. The main differential diagnosis is conventional chondrosarcoma, but in problematic cases immunohistochemical studies are useful to establish the correct diagnosis. [ABSTRACT FROM AUTHOR]

Objective: Endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) is the first‐line technique for the sampling of pancreatic lesions. Many factors can influence the diagnostic performance of this procedure, including the use of rapid on‐site evaluation (ROSE). The primary aim of this study was to compare the adequacy, diagnostic yield, accuracy, sensitivity and specificity of EUS‐FNA for solid pancreatic lesions before and after the introduction of ROSE. Methods: This retrospective single‐centre study evaluated all consecutive patients who underwent EUS‐FNA for suspicious, solid pancreatic masses from April 2012 to March 2015. We compared the findings of EUS‐FNA procedures performed during the first and second years following the adoption of ROSE ("ROSE1" and "ROSE2", respectively) to those performed the year before ROSE introduction (the "pre‐ROSE" group). Results: Ninety‐one consecutive patients with a total of 93 pancreatic lesions were enrolled. For the pre‐ROSE, ROSE1 and ROSE2 groups, the adequacy rates were 96.2%, 96.6% and 100%, the diagnostic yield values were 76.9%, 89.7% and 92.1% and accuracy values were 69.2%, 86.2% and 89.5% (p = NS). Sensitivity for malignancy improved from 63.7% in the pre‐ROSE group to 91.7% and 91.2% in the post‐ROSE groups (p < 0.05). Specificity for malignancy was 100% in all groups. Conclusions: ROSE can improve the diagnostic performance of EUS‐FNA for solid pancreatic lesions, although only sensitivity reached statistical significance. [ABSTRACT FROM AUTHOR]

Background: Whether off‐site evaluation of slides by a cytologist viewing the images shared by WhatsApp improves the on‐site evaluation by a pulmonologist (P‐ROSE) remains unknown. This study's objective was to compare the sensitivity of P‐ROSE and WHOSE for adequacy and diagnosis of cytology specimens obtained by endobronchial ultrasound (EBUS)‐guided transbronchial needle aspiration (TBNA). Materials and Methods: We retrospectively reviewed our bronchoscopy database to identify subjects who underwent EBUS‐TBNA for lymph node sampling and had reports of P‐ROSE and WHOSE. We collected data on the adequacy of samples as reported by the pulmonologist (P‐ROSE), remotely by the cytologist (WHOSE), and finally after detailed cytologic evaluation. The study's primary outcome was to assess the increment in sensitivity for adequacy and diagnostic category (using the final cytology report as reference) by incorporating WHOSE. Results: We included 264 (P‐ROSE, n = 184; WHOSE, n = 80) subjects. The sensitivity (95% CI) for sample adequacy by P‐ROSE and WHOSE was 65.3% (57.9%‐72%) and 92% (83.6%‐96.2%), respectively. There was a 26.6% (95% CI, 16%‐35.2%) increment in the sensitivity for adequacy. The sensitivity (95% CI) for diagnosis by P‐ROSE and WHOSE was 53.9% (46%‐61.1%) and 89.8% (79.5%‐95.3%), respectively. There was a 35.9% (95% CI, 23.4%‐45%) increment in the sensitivity for diagnosis with WHOSE. The agreement between P‐ROSE and final cytology in adequacy was poor (κ = −0.023, p = 0.616). The agreement between WHOSE and final cytology was moderate for adequacy (κ = 0.491, p = <0.001). Conclusion: We found WHOSE significantly improves the performance of P‐ROSE for rapid assessment of cytology specimens obtained by EBUS‐TBNA. [ABSTRACT FROM AUTHOR]

Background: Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm arising in the stomach. However, a number of other rare mesenchymal neoplasms do occur at this anatomic site, which often presents a diagnostic challenge for cytopathologists on endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA). Our study aims to selectively present the clinico‐radiological and cytopathological characteristics of these rare "non‐GIST" neoplasms, as well as their differential diagnoses. Material and Methods: We performed a 20 year retrospective search in the cytopathology database of our two large medical institutions for non‐GIST mesenchymal neoplasms arising in the stomach and diagnosed on EUS‐FNA. Data regarding the patients' demographics and radiological findings were analysed. All available cytopathology specimens were reviewed. The cytomorphological characteristics and the accompanying immunohistochemical stains, when available, were subsequently analysed. Results: Twenty‐five cases of gastric mesenchymal tumours were selectively included in the study after excluding all cases of GIST (n = 113) diagnosed on FNA. These cases included 10 leiomyomas (40%), eight schwannomas (32%), five glomus tumours (20%), one perivascular epithelioid cell neoplasm, and one desmoid tumour. The specimen cellularity was variable and ranged from hypocellular to highly cellular. Most smears were composed of spindle cells with a few showing epithelioid morphology. Cell blocks were available in 20 cases and a range of immunohistochemical ancillary studies were performed. DOG‐1, c‐KIT, smooth muscle actin (SMA), and S100‐protein were the most common immunomarkers done. Conclusion: Our study highlights important cytomorphological characteristics of rare mesenchymal neoplasms arising in the stomach. In the appropriate clinical setting and with the help of immunohistochemistry, an accurate diagnosis of these neoplasms can be achieved. [ABSTRACT FROM AUTHOR]

Background: The clinical performance of the Yokohama reporting system for breast cytology remains uncertain. Methods: In this study, we retrospectively evaluated 318 breast fine needle aspirations (FNABs) from Los Angeles County Hospital over a five‐year period, analysing data for breast cytology, histology, and radiology. Results: Among 318 breast FNAB cases, 78.3% (249/318) were benign and 5.3% (17/318) malignant. Of 83 cases with follow‐up histology, 14.5% (12/83) were insufficient, 66.3% (55/83) were benign, and 16.9% (17/83) were malignant. Of 55 benign cases, 61.8% (34/55) were fibroadenoma and 9 (9/55, 16.4%) were fibrocystic changes. Two cases were diagnosed as "atypical" but confirmed "benign" on core needle biopsy (CNB). No "suspicious" cases were found. Seventeen malignant cases were confirmed by CNB, including 70.6% (12/17) invasive ductal carcinoma, 11.8% (2/17) invasive lobular carcinoma, and one malignant phyllodes tumour. Receptor studies on cell blocks of three malignant cases showed concordant results with CNB results. In addition, 82.2% (148/180) of lesions with Breast Imaging‐Reporting and Data System (BI‐RADS) scores of 2 or 3 were benign and 92.3% (12/13) BI‐RADS score 5 lesions were malignant on FNAB. Finally, 90% (67/74) of BI‐RADS 4a lesions were benign, and 97% (36/37) of fibroadenomas were BI‐RADS score 4a. Conclusion: This, by far the largest U.S. breast cytology study, showed 93.3% sensitivity, 100% specificity, 100% positive predictive value, and 98.2% negative predictive value for breast FNAB. Women with breast lesions of BI‐RADS score 3 or less have a low risk of malignancy; FNAB would contribute to the reduction of excisional biopsies. FNAB can be considered as an initial diagnostic tool for BI‐RADS 4 mass/lesions and satellite lesions, as well as for triaging patients. [ABSTRACT FROM AUTHOR]

Background: Papillary thyroid carcinoma (PTC) is the most common primary malignant thyroid neoplasm and malignant diagnosis in thyroid aspirates. Metastatic adenocarcinoma of the lung is an under‐recognised mimicker which overlaps cytomorphologically and immunocytochemically with PTC. This case series reviews thyroid aspirates of metastatic lung carcinomas, aiming to address the similarities and methods of differentiating this entity from PTC. Methods: Thyroid aspirates of metastatic lung carcinomas were obtained by a computerised search. Clinico‐cytological features and ancillary test results were reviewed. A literature review was performed for published cases of metastatic lung carcinomas in thyroid aspirates. Results: A total of 14 cases were found, including nine adenocarcinomas, three TTF1‐positive non‐small cell lung carcinomas (NSCLCs), one small cell carcinoma and one squamous cell carcinoma. The adenocarcinomas and TTF1‐positive NSCLCs displayed PTC‐like features including papillae/papillary‐like fronds (n = 6/12, 50%), nuclear grooves (n = 5/12, 41.7%) and inclusions (n = 1/12, 8.3%), chromatin clearing (n = 3/12, 25%), calcifications (n = 3/12, 25%) and multinucleated giant cells (n = 2/12, 16.7%). Useful distinguishing features observed were prominent nucleoli, coarse chromatin, mitosis, and necrosis. TTF‐1 immunocytochemistry was positive in most cases (n = 5/6, 83.3%), while PAX8 and thyroglobulin were consistently negative. EGFR exon 19 deletion was detected on cell block preparation in a single case, corresponding to its lung primary. The literature search yielded 84 cases of metastatic malignancies, with lung carcinomas comprising of 3.6%–33.3% in case series of metastatic malignancies. Conclusion: Metastatic adenocarcinoma of lung and PTC share significant cytomorphological and immunocytochemical similarities. A high degree of caution, meticulous clinico‐cytological assessment and prudent use of ancillary techniques is necessary to avoid potential misdiagnosis. [ABSTRACT FROM AUTHOR]

Background: Dermal filler injections are being increasingly used as a non‐surgical option for facial cosmetic procedures. However, their use has been implicated in multiple adverse events including immediate, early onset, and late onset complications. Aim: We present a case of dermal filler‐induced foreign body reaction presenting as bilateral parotid lesions and diagnosed using fine needle aspiration. Conclusion: This case elucidate the risk of delayed adverse events in patients with dermal filler injections and stresses the importance of awareness by patients and providers for such events. [ABSTRACT FROM AUTHOR]

Objective: Fine needle aspiration (FNA), followed by core needle biopsy (CNB) when needed, was adopted as the standard care for liver lesions in our institution. This study explores the diagnostic efficacy of combined image‐guided FNA and CNB in liver lesion diagnosis. Method: We retrospectively reviewed all liver FNA cases performed in our institution between January 2010 and September 2018. A total of 550 cases from 531 patients (173 females) with a median age of 59 years (range, 13–90) were identified. All FNA cases were initially assessed with rapid on‐site evaluation, and cell blocks were prepared. A total of 459 FNA specimens with concurrent CNBs were included in the study. Both FNAs and CNBs in the paired sampling were read by a cytopathologist, with expert consultation as needed. Results: The concordance rate between FNA and CNB was 85.2%. Combined FNA/CNB showed higher sensitivity in detecting malignant tumours when compared to FNA or CNB alone (98%, vs 87% and 92%, p < 0.001), especially for detecting metastatic tumours, hepatocellular carcinoma, and haematopoietic neoplasms (98%, 97%, and 94%, respectively; all p < 0.001). Combined FNA/CNB showed a lower false negative rate in malignant tumours than FNA or CNB alone (2%, vs 13% and 8%, p < 0.001). There was no significant difference among FNA, CNB, and combined FNA/CNB in diagnosing benign liver lesions. Conclusions: Combined liver FNA/CNB has high diagnostic efficacy for malignancy and a lower false negative rate than either procedure alone, especially in metastatic tumours, hepatocellular carcinoma, and haematopoietic neoplasms. [ABSTRACT FROM AUTHOR]

Angiomyolipoma, a perivascular epithelioid cell tumour, is easily identifiable as a benign tumour in the kidneys. However, when occurring in extrarenal sites it can mimic malignancy (Cancer Cytopathol. 2017;125:257). Pathologists must be aware of the classical morphological features of this lesion, its pitfalls in extrarenal sites, and the need for immunohistochemistry in order to establish the correct diagnosis (World J Gastroenterol. 2000;6:608). We report a case of angiomyolipoma with extramedullary hematopoiesis presenting as a large hepatic mass, diagnosed by cytology through endoscopic ultrasound guided fine needle aspiration. Our case exemplifies the classic cytological findings that are important in the differentiation between hepatic angiomyolipoma (HAML) and differentials in this organ such as hepatocellular carcinoma (HCC) and focal nodular hyperplasia. A brief literature review and comparison of significant features between HAML and HCC are presented. [ABSTRACT FROM AUTHOR]

Objective: To analyse the cytopathological features of fine needle aspiration (FNA) in angioimmunoblastic T‐cell lymphoma (AITL) diagnostics. Methods: Fine needle aspiration lymph node biopsy samples from 12 patients with AITL were collected at a single centre between January 2014 and December 2020. The clinical, cytological and histopathological characteristics were retrospectively analysed. Results: Three male and six female patients with AITL who had a median onset age of 65 years (range 51‐74 years) and a mean follow‐up period of 29 months (range 12‐47 months) were included. The FNA cytological and morphological analysis of the reactive lymph node background revealed diffusely distributed non‐homogeneous mixed lymphocytes, including mature small lymphocytes, medium‐sized lymphoid cells, immune cells, and plasma cells; some mixed eosinophils, macrophages, and an occasional mixture of visible and medium‐sized lymphocytes and epithelioid cells were observed. Mitotically active lymphocytes and sporadic pigmented bodies were observed occasionally. An abnormal proliferation of follicular dendritic cells observed under the microscope is important for AITL diagnosis, and these cells are often distributed in a scattered pattern of small clusters with many nuclear morphologies. Branched capillaries are another important diagnostic clue. Two patients with AITL who achieved clinical remission after treatment experienced recurrence and were diagnosed using FNA and cell block immunohistochemistry. Conclusions: Fine needle aspiration provides clues for the diagnosis of AITL in special clinical situations, and cell block immunohistochemistry is worthy of further exploration. [ABSTRACT FROM AUTHOR]

Introduction: Molecular testing for genetic alterations in thyroid neoplasms, including BRAF V600E (BRAF) mutation, are often applied to thyroid aspirates falling into the Bethesda System for Reporting Thyroid Cytopathology indeterminate categories. Current methods typically use dedicated aspirated material, without morphological determination of containing the cells of interest and may be of elevated cost. We describe our experience with BRAF mutation analysis on material obtained from Papanicolaou (PAP)‐stained ThinPrep® (TP) slides. Methods: Eighty‐three cases collected between 2012 and 2019 with more than 100 cells were selected. An electronic record of a whole slide scan was made for each case before testing. The coverslips were removed, and DNA was extracted from material scraped from each slide using the Qiagen QIAamp DNA FFPE Tissue Kit. BRAF testing was performed using a highly sensitive mutation detection assay, either COLD‐PCR, castPCR, or droplet digital PCR. Results: Fourteen out of 83 cases had a BRAF mutation. Of these, 8 were classified as atypia of undetermined significance or suspicious for malignancy in which follow‐up showed conventional papillary thyroid carcinoma in 5 out of 6 cases. The specificity and positive predictive value were 97% and 91%, respectively. Conclusions: BRAF mutation analysis can be performed on material obtained from routine clinical PAP‐stained TP slides. As a first step, this unconventional effective approach may reduce costs related to the molecular evaluation of thyroid nodule aspirates and provides the opportunity for cytomorphological confirmation that the cells of interest are present in material submitted for BRAF mutation analysis. [ABSTRACT FROM AUTHOR]

Introduction: Demand for rapid on‐site evaluation (ROSE) of fine needle aspiration (FNA) cytology is rising and the role is increasingly being performed by non‐medical cytologists. Undergraduate training for cytologists has traditionally focused on laboratory‐based procedural activities and their theoretical underpinning, with minimal attention given to communication and other skills required to operate in an interprofessional setting. We evaluated the effectiveness and student reaction to a simulation‐based education (SBE) exercise in ROSE designed to fill this void. Methods: We designed and evaluated an SBE exercise based on FNA ROSE across two tertiary institutions with 79 students. The exercise accurately reproduced the demands on cytologists operating as part of a multi‐disciplinary team in a time‐ pressured environment. Findings: Pre‐ and post‐simulation questionnaires indicated an improvement in technical knowledge related to the procedure. Students' perception of their competence and confidence in their role also improved significantly post simulation. Students uniformly found the exercise engaging and a valuable addition to their curriculum. Discussion: The simulation successfully provided a pseudo‐clinical environment that highlighted the realities of practising technical and diagnostic tasks under time pressure and interacting with other health professionals to provide an optimal patient outcome. The exercise is a useful supplement to on‐the‐job training for ROSE. [ABSTRACT FROM AUTHOR]

Introduction: Lymph node (LN) fine needle aspiration cytology (FNAC) is a safe, quick, inexpensive, reliable, and minimally invasive technique for the diagnosis of lymphadenopathies. Recently, an international committee of experts proposed guidelines for the performance, classification, and reporting of LN‐FNAC: the Sydney System. We set out to analyse the diagnostic performance of the Sydney System in a retrospective study. Methods: We retrieved 1458 LN‐FNACs, reformulated the diagnoses according to the Sydney System, and compared them to the histological control where available (n = 551, 37.8%). Results: The risk of malignancy for each of the five categories was 66.7% for inadequate/insufficient, 9.38% for benign (overall: 0.84%), 28.6% for atypical, 100% for suspicious and 99.8% for malignant. LN‐FNAC showed a sensitivity of 97.94%, a specificity of 96.92%, a positive predictive value of 99.58%, and a negative predictive value of 86.30%. Conclusions: These data support the usage of LN‐FNAC as an agile first‐level technique in the diagnosis of lymphadenopathies. The Sydney System supports and enhances this role of LN‐FNAC, and its adoption is encouraged. In negative cases, coupled with ancillary techniques, LN‐FNAC can reassure the clinician regarding the benignity of a lymphadenopathy and indicate the need for clinical follow‐up, which will catch possible false negatives. In positive cases, LN‐FNAC can provide sufficient information, including predictive biomarkers, to initiate management and obviate the need for subsequent, more invasive procedures. Given its speed, minimal invasiveness, and low cost, LN‐FNAC can be performed in most cases, even when more invasive techniques are not feasible. [ABSTRACT FROM AUTHOR]

Objective: Fine needle aspiration cytology (FNAC) is a valuable, noninvasive technique for head and neck pathology diagnosis. The objective of case images was to highlight the utility of FNAC for diagnosing suspected cases of ameloblastoma. Method: FNAC smears of suspected cases of ameloblastoma were evaluated using their cellular and stromal features. Results: Cellular features and background of smears exhibited characteristics of ameloblastoma. Predominant features included clusters of ameloblast‐like cells and spindle cells in a myxoid background. Conclusion: Careful evaluation of FNAC helps diagnose ameloblastomas and must be considered a vital diagnostic tool. [ABSTRACT FROM AUTHOR]

Introduction: The cytopathology and diagnostic accuracy of salivary gland (SG) polymorphous adenocarcinoma (PAC) is the subject of a limited number of reports. We undertook a review of our experience with fine needle aspiration (FNA) biopsy and PAC. Materials and methods: A search was made of our cytopathology files for PAC cases that also had histopathological confirmation. FNA biopsy smears and cell‐blocks were performed and examined using standard techniques. Results: Eight FNA biopsy cases of histologically proven PAC from 7 patients [F:M = 1.3:1, age 39‐75 years, mean = 58] met study inclusion. Metastatic aspirates were most common (4), followed by 3 primary cases and 1 locally recurrent neoplasm. Primary FNA sites included hard palate (1 case), lip (1), and lateral tongue (1); all metastatic sites were in the neck. A precise cytologic diagnosis was made in 38% of cases; however, when applying the Milan classification system, 100% could be categorised as either malignant or of uncertain malignant potential. Ancillary immunohistochemical testing performed in 44% of the cases was non‐specific. Cytologic smears showed cellular uniformity and structural variety of cell groups with tubular, branching, cribriform, and convex patterns as well as variable, but occasionally abundant globular myxoid stroma leading to confusion with adenoid cystic carcinoma. Conclusion: The imitative cytopathology of PAC with other SG neoplasms as well as its infrequency in routine FNA biopsy practice makes specific interpretation difficult, but using a classification system allows for appropriate patient management. Molecular testing in future specimens holds promise for enhancing diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Objective: Rapid on‐site evaluation (ROSE) is a fine needle aspiration (FNA) technique for ensuring sampling adequacy and triaging samples. The Milan system for reporting salivary gland cytopathology (MSRSGC) is a standardised reporting system which aims to improve risk stratification. There is scant literature on the diagnostic value and agreement of MSRSGC on ROSE with final cytological diagnosis in salivary gland FNAs. We aimed to assess the concordance of MSRSCG categorisation and diagnosis on ROSE with final cytological and histological diagnosis. Methods: This prospective study included consecutive salivary gland FNAs for which ROSE was performed over a six‐month period. MSRSGC category and diagnosis on ROSE were compared with the final cytological diagnosis and MSRSGC category, and histopathological diagnosis, where available. Results: Sixty salivary gland aspirates were included. The adequacy rate with ROSE was 100%. Using the MSRSGC classification during ROSE, 26 (43.2%) samples were categorised as benign neoplasm, 21 (35%) as malignant neoplasm, 9 (15%) as non‐neoplastic, and one each (1.7%) belonged to the remaining four categories. MSRSGC categorisation on ROSE concurred with final the cytological diagnosis in 58/60 cases (96.7%). Discrepancies in MSRSGC categories on ROSE included one atypia of undetermined significance with final report as non‐neoplastic, and one non‐diagnostic as suspicious for malignancy. Good correlation of MSRSGC categories on ROSE with final histopathological diagnosis (88.9% concordance) was also noted. Conclusions: MSRSGC on ROSE shows good concordance with final cytology and histopathology diagnosis, indicating that categorisation according to MSRSGC has utility in ensuring that adequate material is obtained and triaged appropriately for the diagnosis of salivary gland aspirates. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the diagnostic accuracy of a different sample preparation protocol for fine needle aspiration cytology (FNAC) of thyroid nodules established during the COVID‐19 pandemic. Methods: From April 2020, conventional smears during FNAC were ceased according to World Health Organization recommendations due to the increased infection risk for operators, and a new protocol using only liquid‐based cytology (LBC) was adopted. FNACs performed between April and July 2020 (COVID‐19 group) were retrospectively compared with those from December 2019 through March 2020 (Pre‐COVID‐19 group). The distribution of diagnoses based on SIAPEC‐IAP categories and the concordance between cytological and histological results were compared using the chi‐squared test. Results: Categories based on FNAC for 90 and 82 thyroid nodules in the Pre‐COVID‐19 and COVID‐19 groups showed no significant difference in distribution (P =.081), with the following respective cases (and percentages): TIR1, 7 (8%) and 8 (10%); TIR1C, 0 (0%) and 6 (7%); TIR2, 59 (66%) and 55 (67%); TIR3A, 8 (9%) and 5 (6%); TIR3B, 1 (1%) and 2 (3%); TIR4, 5 (6%) and 1 (1%); and TIR5, 10 (12%) and 5 (7%). Among patients with potentially malignant lesions, surgery was performed for 12/16 (75%) nodules in the Pre‐COVID‐19 and 7/8 (88%) nodules in the COVID‐19 groups, with no significant differences between cytological and histological diagnoses (P =.931). Conclusion: The new LBC‐only protocol provided similar diagnostic accuracy in comparison with conventional smears, and can be effectively applied during a viral pandemic improving operator safety. [ABSTRACT FROM AUTHOR]

Intraocular metastases from the lung are a common occurrence and an important differential for cytopathologists reading fine needle aspiration biopsies (FNAB). It is a particularly challenging diagnosis when the patient has had no previous diagnosis of lung cancer. We present two cases of intraocular metastases from lung primaries, and we discuss the clinical, radiological, and cytopathological features that help differentiate intraocular metastases of lung primary from other intraocular tumours, in the setting of FNAB. We also discuss the importance of recognising the spectrum of FNAB cases that can be seen specific to an institution, which may vary according to different patient populations. A thorough metastatic workup and ancillary testing, such as IHC or molecular genetics, ensures an accurate diagnosis. Intraocular metastases from the lung are a common occurrence and an important differential for cytopathologists reading fine needle aspiration biopsies (FNAB). It is a particularly challenging diagnosis when the patient has had no previous diagnosis of lung cancer. Reports of two cases of intraocular metastases from lung primaries are presented, as well as the clinical, radiological, and cytopathological features that help differentiate intraocular metastases of lung primary from other intraocular tumours, in the setting of FNAB. [ABSTRACT FROM AUTHOR]

Objectives: The practice of cytopathology has evolved over the past decade with a growing need for doing more with less tissue. Changes in clinical practice guidelines and evolving needs in tissue acquisition for diagnosis and treatment have affected various areas of cytopathology in different ways. In this study, we evaluated the changing trends in cytopathological practice at our institution over the past decade. Methods: We performed a retrospective review of our institutional database for cytopathology cases from calendar years 2009 (n = 28038) and 2019 (n = 31386) to evaluate the changing trends in practice. Results: The overall number of exfoliative cases decreased 10% over the past decade, primarily due to a 64% decrease in gynaecological Pap testing. However, the volume of serous body cavity and cerebrospinal fluids increased 125% and 44%, respectively. The overall volume of fine needle aspiration (FNA) cases increased 38% from 2009 to 2019. The number of FNA cases increased across most body sites, driven primarily by a 180% increase in endobronchial ultrasound‐guided transbronchial needle aspiration cases. In contrast, breast FNA volume decreased 43%. Ancillary studies increased substantially over the past decade, including immunostains (476%) and molecular testing (250%). Conclusions: The trends in our cytopathological practice showed an increased volume of cases, especially in non‐gynaecological specimens. As expected, the number of FNA cases used for immunostains and molecular testing increased substantially, indicating an upward trend in ancillary studies in cytopathological practice. The trends in our cytopathological practice showed an increased volume of cases, especially in non‐gynaecological specimens. The number of FNA cases used for immunostains and molecular testing increased substantially, indicating an upward trend in ancillary studies in cytopathological practice. [ABSTRACT FROM AUTHOR]

Cytological specimens, which are obtained by minimally invasive methods, are an excellent source of diagnostic material. Sometimes they are the only material available for diagnosis as well as for prognostic/predictive markers. When cytomorphology is not straightforward, ancillary tests may be required for a definitive diagnosis to guide clinical management. Immunocytochemistry (ICC) is the most common and practical ancillary tool used to reach a diagnosis when cytomorphology is equivocal, to differentiate entities with overlapping morphological features, and to determine the cell lineage and the site of origin of a metastatic neoplasm. Numerous immunomarkers are available, and some are expressed in multiple neoplasms. To rule out entities within a differential diagnosis, the use of more than one marker, sometimes panels, is necessary. ICC panels for diagnostic purposes should be customised based on the clinical context and cytomorphology, and the markers should be used judiciously to preserve material for additional tests for targeted therapies in the appropriate setting. This review offers a practical guide for the use of ICC for diagnostic cytopathology, covering the most commonly encountered non‐hematolymphoid diagnostic scenarios in various body sites. Immunocytochemistry (ICC) is the most common and practical ancillary tool used to reach a diagnosis when cytomorphology reaches its limits. Numerous immunomarkers are available, and some are expressed in multiple neoplasms therefore use of more than one marker or sometimes panels are necessary. ICC markers/panels for diagnostic purposes should be customized based on the clinical context and cytomorphology. [ABSTRACT FROM AUTHOR]

Background: Intraductal papillary mucinous neoplasm (IPMN) constitutes up to 20% of all pancreatic resections, and has been increasing in recent years. Histomorphological findings of IPMN are well established; however, there are not many published papers regarding the cytological findings of IPMN on fine needle aspiration (FNA) specimens. We review the cytomorphological features, molecular profile, imaging findings, and prognosis of IPMN. Methods: The English literature was thoroughly searched with key phrases containing IPMN. Observations: IPMN is a rare entity, affecting men and women equally and is usually diagnosed at the age of 60‐70 years. The characteristic imaging features include a cystic lesion with associated dilatation of the main or branch pancreatic duct, and atrophy of surrounding pancreatic parenchyma. Cytomorphological features of IPMN include papillary fragments of mucinous epithelium in a background of abundant thick extracellular mucin, a hallmark feature. IPMNs should be evaluated for high‐grade dysplasia, which manifests with nuclear atypia, nuclear moulding, prominent nucleoli, nuclear irregularity, and cellular crowding. Molecular profiling of IPMN along with carcinoembryonic antigen and amylase levels is useful in predicting malignancy or high‐grade dysplasia arising in IPMN. Overall, the prognosis of IPMN is excellent except in those cases with high‐grade dysplasia and malignant transformation. Postoperative surveillance is required for resected IPMNs. Conclusion: IPMN requires a multidisciplinary approach for management. Cytomorphological findings of IPMN on FNA, in conjunction with tumour markers in pancreatic fluid cytology and imaging findings, are of paramount importance in clinical decision‐making for IPMN. Intraductal papillary mucinous neoplasm (IPMN) constitutes up to 20% of all pancreatic resections. Cytomorphological features in conjunction with tumour marker levels and molecular markers in pancreatic fluid, are helpful for predicting high‐grade dysplasia or adenocarcinoma preoperatively. Management of IPMN requires a multidisciplinary approach. [ABSTRACT FROM AUTHOR]

Salivary carcinoma ex pleomorphic adenoma with myoepithelial differentiation may be underdiagnosed due to morphological similarity to pleomorphic adenoma. [ABSTRACT FROM AUTHOR]

Introduction: Air‐dried slide preparation for fine needle aspiration cytology procedures is currently considered unsafe because of the risk of infectious aerosols of coronavirus 19. This study compares the safety and accuracy of two different protocols, one with and one without air‐dried slides. Methods: Starting from 3 March 2020, we discontinued the use of air‐dried slides during breast fine needle aspiration procedures. We selected cases collected during two periods: 2 months before and 2 months after 3 March. In both groups, the number of procedures was recorded together with the distribution of the diagnostic categories and the concordance between cytological and histological results on surgical specimens for lesions suggestive of malignancy, using the chi‐squared test. Results: Of the 100 procedures performed during the pre‐COVID‐19 period, 55% were negative (C2), 3% were non‐diagnostic (C1) and 40% were positive (C4 or C5). Of the 75 procedures obtained during the COVID‐19 period, 44% were negative (C2), 2.7% were non‐diagnostic (C1) and 52% were positive (C4 or C5). Despite the use of a new protocol during the COVID‐19 period, we observed concordance between cytological and histological results for lesions suggestive of malignancy. There was no statistically significant difference concerning the distribution of the diagnostic categories in the two groups. Conclusions: Taking into account the slightly lower number of procedures being analysed during the COVID‐19 period, the introduction of a new protocol that does not include air‐dried slides is safe and reliable. The pandemic period due to COVID19 has changed many methods in routine hospital and laboratory practice. Air‐dried slides, due to their risky preparation, should be avoided but cytologists lose the optimal definition of cytoplasmic and nuclear features provided by that method of preparation. A new protocol was introduced in our practice that appears to be safe and reliable. [ABSTRACT FROM AUTHOR]

The cytological features of granular cell tumour (GCT) are generally quite typical but, in some cases, the fine needle aspiration cytology (FNAC) diagnosis of GCT may be difficult or impossible because of unusual sites of onset or equivocal cytological features. In this report, two GCTs with atypical FNAC features are described in order to investigate the causes and provide possible diagnostic tips. From a series of nine histologically proven GCTs, two inconclusive FNAC cases were retrieved. Smears were poorly cellular showing isolated naked nuclei, anisonucleosis, granular chromatin and occasional small nucleoli. The background was finely granular in one case. Histological controls of these cases revealed marked fibrosis. Tumour‐associated fibrosis in GCT is variable and does not seem to influence clinical behaviour but it influences the harvest and the integrity of granular cells collected by FNAC. When GCT smears are poorly cellular, attention should be paid to the granular background and to the few granular cells, if any, as they might be the only features to suggest a GCT. Fine needle aspiration cytology of granular cell tumour (GCT) may be hampered by scanty cellularity and equivocal cytological features. Tumour‐associated fibrosis in GCT is variable and may influence the harvest and the integrity of granular cells collected by fine needle aspiration. When GCT smears are equivocal and poorly cellular, attention should be paid to the granular background and to the few granular cells, if any, as they may suggest a GCT. [ABSTRACT FROM AUTHOR]

Introduction: The American Society of Clinical Oncology (ASCO)‐endorsed College of American Pathologists guideline recommends high‐risk human papillomavirus (HPV) testing for metastatic squamous cell carcinoma (SCC) of lymph nodes level II/III of unknown primary. Herein, the performance of HPV‐RNA in situ hybridisation (ISH) in detection of HPV‐related SCC is evaluated implementing the ASCO guideline recommendations. Methods: Eighty head and neck (HN) SCC fine needle aspirations, which utilized HPV‐RNA ISH/P16, were evaluated at Johns Hopkins Hospital (2015‐2018) to investigate their performance and concordance with histology. The results were compared to a prior study of 59 HNSCCs, which HPV‐DNA ISH. Results: Of the 80 reviewed fine needle aspirations, 65 (50 male, 15 female) were included. The mean age was 63.2 ± 14.0 years. The most common site was neck lymph nodes (47, 72.3%). Fifty‐five cases (84.6%) were accompanied by concurrent core biopsy, and 48 cases (59.4%) had surgical follow‐ups. HPV‐RNA ISH was positive in 44 (67.7%), and P16 was strongly positive in 46 (70.8%). The HPV‐RNA ISH/ P16 concordance rate was 92.3% on cytology material. The cytology/surgical concordance rate for HPV‐RNA ISH was 88.9% (16/18). There was a discordance between the results in five cases (7.7%; HPV‐RNA ISH‐/P16+). Conclusion: HPV‐RNA ISH is a robust and reliable method for detecting HPV‐related HNSCC on cytology material showing concordance rate of 92.3% between HPV‐RNA ISH and P16, which is a sensitive but non‐specific marker. Compared to HPV‐DNA ISH, HPV‐RNA ISH reproducibly identifies HPV‐related HNSCC with fewer discrepancies between cytology and histology. The findings of this study are in agreement with the ASCO recommendations. HPV‐RNA ISH is a robust and reliable method for detecting head and neck squamous cell carcinoma (HNSCC) of unknown primary on metastatic lymph nodes (levels II and III) or neck masses on cytology. Cytology material provides sufficient material for HPV RNA ISH and P16 testing which is in agreement with the ASCO guideline recommendations on HNSCC of unknown primary. [ABSTRACT FROM AUTHOR]

Introduction: The Bethesda System recommends repeat fine needle aspiration (rFNA) as a management option for nodules classified under the non‐diagnostic (ND) and atypia of undetermined significance (AUS/FLUS) categories. We evaluated the impact of an rFNA in diagnostic resolution and the role of early (≤3 months) vs delayed (more than 3 months) rFNA of nodules initially diagnosed as ND and AUS/FLUS. Methods: We retrospectively collected all thyroid FNA performed in a 4‐year period with repeat aspiration. For cases initially signed out as ND or AUS/FLUS, diagnostic resolution was defined as a change to a Bethesda System category other than these two on rFNA. Comparison and regression models were fitted to identify the impact of time of rFNA on diagnostic resolution. Results: In total, 184 cases were initially assigned as ND and 143 as AUS/FLUS, with overall diagnostic resolution rates for the reassessment of these nodules calculated at 70.1% and 62.9%, respectively. For ND cases, time of rFNA was not significantly associated with diagnostic resolution (P >.05). For AUS/FLUS nodules, however, repeat aspiration performed in more than 3 months after the initial diagnosis was 2.5 times more likely to achieve a resolution in diagnosis than early rFNA (P =.024). Conclusions: Repeat aspiration of ND and AUS/FLUS nodules helped define diagnosis for the majority of cases, being highly effective in determining correct patient management. For AUS/FLUS nodules, repeat aspiration performed more than 3 months after the initial diagnosis was associated with a higher diagnostic resolution. This retrospective study has shown that repeat aspiration of nondiagnostic/indeterminate (AUS) thyroid nodules resulted in a definitive diagnosis in the majority of cases. No statistical difference was seen for diagnostic resolution rates before and after three months. These results may stimulate further prospective, large centre, randomized studies, to determine the optimal timing for resampling thyroid nodules with inconclusive diagnoses. [ABSTRACT FROM AUTHOR]

Introduction: The dramatic spread of COVID‐19 has raised many questions about cytological procedures performed in and out of the laboratories all over the world. Methods: We report a heterogeneous series of fine needle aspirations performed during the period of phase 1 of the lockdown for the COVID‐19 pandemic to describe our experience and measures taken during this period. Results: A total of 48 fine needle aspirations (ultrasound, computed tomography and endoscopic ultrasound guided) were processed and reported. Conclusions: Pre‐existing procedures have been modified to allow healthcare professionals to work safely ensuring patients the necessary assistance with samples suitable for cellularity, fixation and staining for an accurate cytological diagnosis. The dramatic spread of COVID‐19 has posed many questions about cytological procedures performed into and out of the laboratories all over the world. Many of the pre‐existing procedures have been modified and will have to be further modified to allow healthcare professionals to work safely. [ABSTRACT FROM AUTHOR]

Objectives: The accuracy of a cytological diagnosis obtained by fine needle aspiration is influenced by several factors including the technique used and the experience of both the aspirator as well as the cytologist. In this project we planned to evaluate the interobserver differences of thyroid nodule cytopathology in our medical centre. Methods: The study was conducted using retrospective pathology reports from a single academic centre from August 2013 to September 2017. We compared the sensitivity, specificity, negative and positive predictive values, malignancy rates, and accuracy of two cytopathologists who evaluated thyroid nodules. Results: We included 287 fine needle aspirations of thyroid nodules in the study. Approximately one fifth (18.5%) of patients had surgery and the rate of malignancy was 40%. There was a similar frequency of use of all thyroid Bethesda system (TBS) categories with the exception of TBS 3 (8.0% and 21.2%, P =.01). As a consequence, the malignancy rate was different in TBS 3 category (40% vs 17%, P =.545). Conclusions: There are interobserver differences in the evaluation of thyroid nodules. Clinicians should be aware of such differences because they affect the malignancy rate in each TBS category. In this retrospective study we compared the sensitivity, specificity, negative and positive predictive values malignancy rates, and accuracy between two cytopathologists who evaluated thyroid nodules. There was a similar frequency of use of all thyroid Bethesda system categories with the exception of category 3, and as a consequence, the malignancy rate was different in this category. [ABSTRACT FROM AUTHOR]

Fine needle aspiration cytology (FNAC) is a widely accepted safe, simple and rapid diagnostic procedure used in the examination of neoplastic and non‐neoplastic lesions of various locations. Since its introduction, FNAC has developed into an effective diagnostic tool practiced in a large majority of medical centres evaluating and treating oncological patients. The role of FNAC has been limited in the examination of primary soft tissue lesions, however, as many physicians working in this area recommended against using FNAC. An increasing use of minimally invasive diagnostic procedures in the last decade has resulted in a better acceptance of FNAC as a first‐line approach or as a complementary tool to core needle biopsy in the diagnosis of musculoskeletal lesions. This review discusses the role and value of FNAC in the evaluation and treatment of soft tissue tumours based on the experience gathered over the course of 48 years at the Sarcoma Center in Lund, Sweden. FNAC reports most often provide diagnostic information allowing the initiation of treatment or, when definitive diagnosis cannot be rendered from a cytological examination, guiding the continued diagnostic investigation. The main advantages of soft tissue FNAC are good sensitivity and specificity, low morbidity, speed of diagnosis, and low cost/benefit ratio. The most important disadvantages stem from limited experience in cytological diagnosis of soft tissue tumours and a lack of standardised and uniform reporting system for soft tissue FNAC. Despite several reviews on the cytologic diagnosis of soft tissue tumors, the role of cytological examinations compared to histological examination in evaluating soft tissue tumors remains controversial. This review discussed the role and value of FNAC in the evaluation and treatment of soft tissue tumors. [ABSTRACT FROM AUTHOR]

Objective: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been proved to be safe, efficient and reliable in the diagnosis of pancreatic lesions. This study evaluated specimen adequacy, diagnostic criteria of various pancreatic neoplasms and contamination from the gastrointestinal (GI) tract. Methods: EUS-guided FNA of the pancreas and subsequent surgical resections performed at the University of California Irvine Medical Center during February 1996-October 2000 were retrospectively selected. Modified Papanicolaou staining method was used for immediate evaluation and cell block prepared. Results: A total of 267 cases were available for review, including 147 (55.1%) positive/suspicious, 10 (3.7%) atypical, 96 (36.0%) negative and 14 (5.2%) unsatisfactory cases. Eighty-six (58.5%) positive/suspicious cases had histological confirmation and 12 (8.3%) had lymph node or distant metastases by cytology. Three atypical, two negative, and two unsatisfactory cases proved to have adenocarcinoma. Contamination from duodenum, stomach or pancreas was found in 77 positive/suspicious, three atypical and 90 negative cases. The sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were 94.6%, 100%, 95.6%, 100%, 82% respectively. Conclusions: EUS FNA is efficient and accurate in the diagnosis of pancreatic neoplasms in adequate samples. Contamination from the GI tract should be well recognized to avoid misinterpretation.

Objective: To investigate the diagnostic utility of fine needle aspiration (FNA) smear, cell block (CB), flow cytometry (FC) and tuberculosis polymerase chain reaction (Tb‐PCR) analysis for Kikuchi's disease (KD). Methods: A total of 173 FNA biopsy samples were collected using a Youyi aspirator. KD was diagnosed by FNA smear, with or without, CB, FC and Tb‐PCR. Results: Out of 173 patients, 131 (75.7%) were female and 126 (72.8%) aged 21‐40 years. Of these, 171 patients (98.8%) presented with painful enlarged cervical lymph nodes. All cytological samples identified intracellular apoptotic debris embedded in the cytoplasm of crescentic and phagocytic macrophages. In 24 cell‐blocks (CBs), clusters of CD123 positive plasmacytoid monocytes were observed in KD. FC and CBs showed non‐specific lymphoid hyperplasia in nine cases with suspicious lymphoma. Tb‐PCR was negative in five cases with suspicion of tuberculosis. Conclusions: In summary, FNA biopsy is a fast, reliable, and relatively inexpensive diagnosis tool for KD. CB preparation is an important adjunct method for the diagnosis of KD. The authors investigated the diagnostic utility of fine needle aspiration (FNA) smear, cell block (CB), flow cytometry (FC) and tuberculosis PCR (Tb‐PCR) analysis for Kikuchi's disease (KD). They found that FNA biopsy allows cytopathologists to result in a fast, reliable, and relatively inexpensive diagnosis for KD. [ABSTRACT FROM AUTHOR]

Objective: The aim of this analysis was to describe the cytopathology spectrum of peripheral neuroblastic tumours (NTs) including neuroblastoma (NB), ganglioneuroblastoma (GNB) and ganglioneuroma (GN). Feasibility of applying the International Neuroblastoma Pathology Classification (INPC) to further subtype NTs in cytology was evaluated. Methods: All peripheral NTs reported on fine needle aspiration during 2011‐2015 were retrieved and detailed cytomorphological evaluation was performed. Based on INPC criteria, NBs were further categorised as undifferentiated, poorly differentiated and differentiating subtypes. Mitotic‐karyorrhectic index was evaluated. Immunocytochemistry on cell blocks was reviewed wherever available. MYCN amplification by fluorescence in situ hybridisation was performed in 11 cases on smears. Results: A total of 90 cases including 83 NBs, six GNB and one GN were evaluated. The age range was 12 days‐12 years, with 55 males and 45 females. Both the primary and metastatic locations were aspirated. Applying the INPC criteria, there were 61 poorly differentiated, 14 undifferentiated, eight differentiating NB and six GNB. Immunocytochemistry on cell blocks showed positivity for at least two neuronal markers in NB. Mitotic‐karyorrhectic index was high in 63, low in 22 and intermediate in two cases, respectively. MYCN amplification by fluorescence in situ hybridisation was feasible on smears and was amplified in 6 out of 11 cases tested. Conclusion: Peripheral NT types including NB, GNB and GN have distinctive cytomorphology. NBs can be further subtyped as undifferentiated, poorly differentiated and differentiating subtypes as per INPC criteria. Neuroblastoma can be categorized further as per International Neuroblastoma Pathology Classification (INPC) as undifferentiated, poorly differentiated and differentiating subtypes on cytology which is of prognostic relevance. MYCN amplification by FISH adds value to cytodiagnosis. [ABSTRACT FROM AUTHOR]

Objective: Our objective was to evaluate the disease spectrum of thyroid cytopathology and correlation of the Bethesda reporting system with final histopathology in our medical centre. Methods: This retrospective study was conducted from histopathology reports from Galilee Medical Center between August 2013 and September 2017. Results: A total of 287 thyroid fine needle aspirations were included in the study. The majority (55.1%) of these were benign (B2). Surgery was performed on 53 cases and the total malignancy rate was 39.6%. Our study had a favourable accuracy rate of 70%. A B4 Bethesda category had a higher malignancy rate (50%) than previously reported. Conclusion: We found a higher malignancy rate (50%) based on the Bethesda B4 category of the fine needle aspirations in our series, yet it is based on a small sample. The differences in malignancy rates between centres have an important impact on clinical decisions. In this retrospective study we reviewed thyroid fine needle aspirations and compared them to final pathology. We found an accuracy rate of 70%, and a higher Bethesda 4 category malignancy rate than previously reported. [ABSTRACT FROM AUTHOR]

Introduction: There are many merits to fine needle aspiration cytology (FNAC) in evaluation of palpable breast lesions. We set out to determine the concordance of breast FNAC interpretation with subsequent surgical pathology in the resource‐limited healthcare setting of rural Kenya. Methods: African Inland Church Kijabe Hospital electronic pathology files were retrospectively reviewed from 1/1999‐9/2017. All breast FNAC cases and subsequent surgical pathology specimens were identified. FNAC interpretations were categorised according to the International Academy of Cytology Yokohama codes: insufficient; benign; atypical favour benign; suspicious favour malignant; and malignant. Surgical pathology results were categorised as benign or malignant. Results: In total, 695 breast FNACs were identified. A total of 219 (31.5%) had subsequent surgical pathology. Average patient age was 39 years (range 13‐88); 95% were female. Nearly all (98%) lesions were palpable. FNAC interpretive categorisation was as follows: 20 (9%) insufficient, 103 (47%) benign, 16 (7%) atypical, 24 (11%) suspicious and 56 (26%) malignant. On histopathology, there were 141 (64%) benign cases and 78 (36%) malignancies (Table 1). The sensitivity of FNAC for detecting malignancy was 85%; specificity was 75%. Positive and negative predictive values were 69% and 88%. Diagnostic concordance between FNAC and histopathology was 79%. For definitively diagnostic FNAC categories, diagnostic concordance was 89%. On histopathology, malignant diagnoses were given in 0 insufficient, 12 (12%) benign, 4 (25%) atypical, 11 (46%) suspicious and 51 (91%) malignant cases. There were five false‐positive cytopathology interpretations and 12 false‐negatives. Conclusions: FNAC remains a valuable tool in evaluation of palpable breast lesions in resource‐limited healthcare settings. In the workup of non‐cystic breast lesions, core needle biopsy (CNB) has largely supplanted fine needle aspiration cytology (FNAC) as the preferred diagnostic modality, yet there are many merits to FNAC in evaluation of palpable breast lesions. This study determined the concordance of breast FNAC interpretation with subsequent surgical pathology in the resource‐limited healthcare setting of rural Kenya and found that FNAC remains a valuable tool in evaluation of palpable breast lesions in resource‐limited healthcare settings. [ABSTRACT FROM AUTHOR]

Background: The recently introduced monoclonal V600E antibody (clone VE1) is likely to be an alternative strategy for detecting this mutation in thyroid lesions. Although VE1 immunostaining and molecular methods used to assess papillary thyroid carcinoma in surgical specimens are in good agreement, evaluation of VE1 in cytology and cell block samples is rarely performed, and its diagnostic value in cytology has not been well established. In this study, we sought to determine if VE1 is suitable for fine needle aspiration (FNA) and cell block methods. Methods: A total of 86 patients who had BRAF V600E mutations were investigated with molecular and immunocytochemical (ICC) analysis in 45 FNA and 41 cell blocks. In total, 83 (96.5%) patients underwent surgical treatment. Assessment of BRAF V600E mutation status was performed in 72 (83.7%) cases. Results: Among the 72 cases analysed, 54 cases agreed (ICC+/BRAF+ or ICC−/BRAF−), seven cases were false positive (ICC+/BRAF−) and 11 cases were false negative (ICC−/BRAF+). False negative cases were not detected in the cell block method. The statistical analysis showed that sensitivity and specificity of ICC for detecting the BRAF V600E mutation were 61% and 77% in FNA samples and 100% and 73% in cell block. Conclusion: The use of antibody VE‐1 is a reliable method and a negative result of VE1 immunostaining might help to save time and money, restricting the molecular test to antibody‐positive cases only. The identification of the aggressive variants of papillary carcinoma might be enabled by the expression of the antibody in neoplastic cells with tall cell features. BRAFV600E staining (VE‐1) is showing promising results in identifying aggressive variants of papillary thyroid carcinoma. It can be performed reliably on thyroid FNA cell block preparations. The current study supports the role of FNA assessment in thyroid carcinomas emphasising the importance of cell block preparations in providing a tool for the preoperative assessment of BRAF V600E mutation status. [ABSTRACT FROM AUTHOR]

Objective: We reviewed the diagnostic utility of combined fine needle aspiration cytology (FNAC) and flow cytometry (FC) in the diagnosis of lymphoid lesions of the head and neck. Method: In total, 1402 patients with combined FNAC‐FC reports were correlated with follow‐up information. Rapid on‐site evaluation (ROSE) of cytological specimens was performed in 52% of cases. Results: In total, 211 lymphoid malignancies were identified, including 198 non‐Hodgkin lymphoma (NHL) and 13 Hodgkin lymphoma (HL). Accuracy measures for NHL were: sensitivity 95.5%; specificity 99.9%; PPV 99.5%; NPV 99.2%; accuracy 99.3%. Only seven of 13 cases of HL were detected by FNAC‐FC. False negative cases included HL (six cases), diffuse large B‐cell lymphoma (four), T‐cell lymphoma (two), follicular lymphoma (one), marginal zone cell lymphoma (one) and B‐cell NHL, not otherwise specified (one). Two false positive results were identified: one immunoblastic hyperplasia reported as suspicious for HL and one case reported as suggestive of NHL that was found to be reactive hyperplasia. Cases collected with ROSE had a significantly lower rate (P < 0.0001) of insufficient cells for FC analysis (7.0%) than cases where ROSE was not performed (16.4%). Sensitivity (P < 0.0001) and NPV (P = 0.0023) were significantly higher for ROSE‐collected specimens. None of the false‐negative NHL cases had ROSE performed. Conclusions: FNAC‐FC is a highly sensitive and specific test for NHL. Diagnostic errors mostly involved HL, large cell lymphomas and T‐cell lymphomas. ROSE results in a significantly higher adequacy rate for FC and higher sensitivity for NHL. A review of combined FNA cytology‐flow cytometry reporting for lymphoid lesions of the head and neck found high accuracy (99.3%) for NHLs. Rare false negative and false positives were identified, mainly with Hodgkin Lymphoma and large cell lymphomas. Specimens collected with rapid on‐site evaluation showed significantly lower inadequate rates and higher sensitivity and negative predictive value for NHLs. [ABSTRACT FROM AUTHOR]

This viewpoint presents a radiologist's perspective of the value that can be added by close collaboration and teamwork with cytopathologist colleagues to maximise specimen quality, adequacy, and patient outcomes. Various models are discussed and service evolution through teamwork emphasised. The importance of utilising ultrasound guidance for fine needle aspiration in head and neck lesions and critical appraisal of the literature are reviewed. This viewpoint presents a radiologist's perspective of the added value of close collaboration and teamwork with cytopathologist colleagues to maximise specimen quality, adequacy, and patient outcomes. Various models are discussed and service evolution through teamwork emphasised. The importance of ultrasound guidance in fine needle aspiration of head and neck lesions and critical appraisal of the literature are reviewed. [ABSTRACT FROM AUTHOR]

Other malignancies with small blue round cell tumour morphology like Merkel cell carcinoma, Ewing sarcoma/primitive neuroectodermal tumour are also salient differentials of this entity. Keywords: axillary lymphadenopathy; fine needle aspiration; metastasis; small cell neuroendocrine carcinoma; urinary bladder EN axillary lymphadenopathy fine needle aspiration metastasis small cell neuroendocrine carcinoma urinary bladder 371 373 3 04/15/21 20210501 NES 210501 CASE HISTORY A 56-year-old diabetic and hypertensive gentleman presented with the chief complaints of left axillary swelling for the previous month. Fine needle aspiration, metastasis, urinary bladder, axillary lymphadenopathy, small cell neuroendocrine carcinoma. [Extracted from the article]

Objective: To perform a retrospective investigation of our institutional experience with salivary gland fine needle aspirations (FNA) through the framework of The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and assess the risks of neoplasm and malignancy for each diagnostic category. Methods: All salivary gland FNAs performed from January 2009 to December 2016 were retrospectively categorised according to the MSRSGC. When available, pre‐operative cytological results were correlated with subsequent histological follow‐up. Results: In total, 893 FNAs were reviewed. The specimens were retrospectively classified as nondiagnostic (ND: 13.5%), non‐neoplastic (NN: 16.1%), atypia of undetermined significance (AUS: 10.8%), benign neoplasm (BN: 34.9%), salivary gland neoplasm of uncertain malignant potential (SUMP: 8.2%), suspicious for malignancy (SM: 2.7%) and malignant (M: 13.8%). Histological follow‐up was available for 429 cases (48%); the majority (68.1%) were benign. The risks of neoplasm and malignancy for each category were as follows: ND: 64.5%, 16.1%; NN: 42.9%, 17.9%; AUS: 79.6%, 30.6%; BN: 100%, 2.2%; SUMP: 100%, 46.6%; SM: 94.7%, 78.9%; and M: 100%, 98.5%. Conclusions: The MSRSGC is a useful classification scheme for stratifying salivary gland lesions according to their associated risk of malignancy and guiding clinicians toward appropriate management. Diagnostic pitfalls are seen in a small proportion of cases and a multidisciplinary approach for assessing salivary gland pathology is essential in their evaluation. The main objective of this study was to assess the diagnostic accuracy of salivary gland fine needle aspirations (FNA) within the framework of the Milan System and evaluate the Milan System for Reporting Salivary Gland Cytopathology as a tool for risk assessment. We document our institutional experience with salivary gland FNAs over an 8‐year period, retrospectively applying Milan System categorizations to cytologic diagnoses, comparing pre‐ and post‐operative diagnoses, and determining risks of neoplasm and malignancy. [ABSTRACT FROM AUTHOR]

Objective: Fine needle aspiration (FNA) biopsy for evaluation of spongiform nodules ≥20 mm or observation without FNA was recommended by American Thyroid Association. However, this was a weak recommendation supported by moderate quality evidence. We aimed to assess malignancy risk in spongiform nodules. Methods: From January 2015 to June 2016, an experienced endocrinologist performed B‐mode greyscale ultrasonography and observed 96 spongiform nodules among 3748 ultrasound procedures. Power Doppler ultrasonography and ultrasound‐guided FNA were performed to 96 spongiform nodules. Both colour elastography and strain ratio measurements of dominantly solid areas were performed. Results: All spongiform nodules had benign cytology. Fifty‐two (54.2%) nodules were ≥20 mm and 44 (45.8%) were smaller than 20 mm in maximum diameter. Presence of ultrasonography features related to malignancy was rare; 2% (n = 2) microcalcification, 9.4% (n = 9) taller than wide shape and 2% (n = 2) marked central blood flow were noted. None of the nodules had two or more suspicious features. Ultrasound elastography findings revealed that dominantly solid components of nodules were usually soft as 66.7% had an elasticity score 1 according to colour scale and mean strain ratio was 1.39 ± 0.99. Conclusions: Follow‐up with ultrasonography seems to be an efficacious method even for spongiform nodules larger than 2 cm. Determination of soft appearance according to colour map on ultrasound elastography and low strain ratio values of dominantly solid areas may be useful to avoid unnecessary biopsies. Follow‐up with ultrasonography seems to be an efficacious method even for spongiform nodules greater than 2 cm. Determination of soft appearence according to color map on real‐time ultrasound elastography and low strain ratio values of dominantly solid areas may be useful to avoid unnecessary fine needle aspiration biopsies. [ABSTRACT FROM AUTHOR]

Objective: Our aim was to evaluate the performance of fine needle aspiration (FNA) as a method for obtaining cellular material for the tissue diagnosis of small solid renal tumours. Methods: Fifty‐five patients with a small solid renal tumour (4 cm or smaller) underwent a FNA biopsy under computed tomography guidance. Direct smears and rinse of needle with Cytolyt® were prepared. The cellular adequacy was divided into three groups: satisfactory cellular material, scant cellular material and noncellular material. Results: Postoperative pathological diagnosis showed 35 clear cell carcinomas, 10 papillary carcinomas, four chromophobe carcinomas, four oncocytomas, one adenoma and one metastatic carcinoma. A total of 21 (38.2%) FNA biopsies belonged to noncellular group. For clear cell carcinomas, the cellularity of satisfactory cellular group, scant cellular group and noncellular group was, respectively, seven (20.0%), nine (25.7%) and 19 (54.3%). Of the 10 papillary carcinomas, nine (90%) and all four chromophobe carcinomas (100%) had satisfactory cellular materials. The percentages of noncellular group among clear cell carcinoma, papillary carcinoma and chromophobe carcinoma were significantly different (P = 0.0020). Fifteen tumours were 2 cm or smaller and 40 tumours were larger than 2 cm. No significant difference was found in the percentage of noncellular material for the tumours 2 cm or less (40.0%) and for the tumours larger than 2 cm (37.5%; P > 0.05). Conclusions: The cellularity of FNA biopsy of small solid renal masses might correlate with the subtype of renal cancers. FNA biopsy was an effective method of tissue sampling for papillary and chromophobe renal carcinomas. [ABSTRACT FROM AUTHOR]