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Pigmented neoplasms of the skin and mucous membranes are a heterogeneous group of benign and malignant neoplasms, some of which are extremely rare in the practice of pediatric oncologist. Orolabial melanosis refers to a benign pigmented pathology of the skin and mucous membranes, requires differential diagnosis with ephelids, melanoma, and when localized on the tongue – with pigmented fungiform papillae of the tongue.This article presents a clinical case of orolabial melanosis with localization on the tongue in a 9-year-old child that was not previously described in the domestic literature. The clinical, dermatoscopic, immuno-morphological and differential diagnostic features of this pathology are described in detail.

Summary Although the morphologic diagnosis of hibernoma is usually straightforward, some hibernomas have atypical morphologic features, mimicking atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLs). In addition, the multivacuolated brown fat cells may be mistaken for lipoblasts by pathologists, especially those without significant soft tissue tumor exposure. Thus, we continue to receive in consultation cases of hibernoma sent for MDM2 fluorescence in situ hybridization testing to exclude ALT/WDL. Testing hibernomas for MDM2 amplification, however, adds cost and delays the final diagnosis. Recently, we have noted expression of neprilysin (CD10, CALLA), a zinc-dependent metalloproteinase involved in the inactivation of various peptide hormones, in brown fat cells, and wished to explore the potential utility of this widely available, inexpensive ancillary test in the differential diagnosis of hibernoma. Formalin-fixed, paraffin-embedded tissue sections from well-characterized cases of hibernoma (n = 48), brown fat (n = 21), ALTs/WDLs (n = 17), pleomorphic liposarcomas (PLPSs) (n = 6), lipomas (n = 5), and fat necrosis (n = 5) were immunostained for CD10, using a commercially available antibody and routine laboratory protocols. CD10 expression was evaluated in both adipocytes and in surrounding stromal cells. The hibernomas occurred in 28 men and 20 women, ranging from 11 to 76 years of age and involved the extremities (n = 25), pelvis (n = 7), abdomen/pelvis/retroperitoneum (n = 7), head and neck region (n = 6), back (n = 2), and chest (n = 1). All showed diffuse, strong CD10 expression in multivacuolated brown fat cells and in the majority of adjacent univacuolated fat cells. Brown adipose tissue from various anatomic structures showed an identical pattern of immunoreactivity. In contrast, CD10 expression was present in the adipocytes of only 3 of 17 (18%) ALTs/WDLs and was absent in lipomas and fat necrosis. Lipoblasts expressed CD10 in 3 PLPSs. Expression of CD10 by surrounding fibroblastic stromal cells was more widespread, present in 13 hibernomas, 10 ALTs/WDLs, 1 instance of fat necrosis, 6 PLPSs, and 4 examples of brown fat. We conclude that immunohistochemistry for CD10 may represent a useful, rapid and inexpensive ancillary test in the differential diagnosis of hibernoma from potential morphologic mimics, especially when morphologic features favor hibernoma. CD10 expression in adipocytes, however, should be rigorously distinguished from fibroblastic stromal cell CD10 expression, a nonspecific finding.

Multiple groups have recently reported involvement of the gallbladder mucosa of immunocompetent patients by cystoisospora organisms. However, this has recently been disproved with the support of molecular and ultrastructural studies. Here we present a summary of these events, recounting how this pseudo-Cystoisospora epidemic began and ended. This review also highlights the important role played by ancillary techniques in supplementing the morphologic diagnosis of pathogens.

Infections of the central nervous system cause significant morbidity and mortality in immunocompetent and immunocompromised individuals. A wide variety of microorganisms can cause infections, including bacteria, mycobacteria, fungi, viruses, and parasites. Although less invasive testing is preferred, surgical biopsy may be necessary to collect diagnostic tissue. Histologic findings, including special stains and immunohistochemistry, can provide a morphologic diagnosis in many cases, which can be further classified by molecular testing. Correlation of molecular, culture, and other laboratory results with histologic findings is essential for an accurate diagnosis, and to minimize false positives from microbial contamination.

BACKGROUND Current clinical practices are shifting towards utilizing less invasive biopsy techniques, including fine needle aspiration (FNA) and needle core biopsies. If a patient has a suspected hematologic malignancy, a portion of the FNA sample is typically submitted for flow cytometry (FC) analysis, providing valuable immunophenotypic data. METHODS FNA specimens were identified via a pathology database search. All cases were morphologic evaluated and a subset of cases were analyzed by FC. RESULTS 245 hematologic FNA specimens were identified; 84% of these cases had an adequate number of cells for FC analysis, and an unequivocal morphologic diagnosis (benign or malignant) was rendered in 85%. The percentage of cases with an unequivocal diagnosis was statistically significantly higher in those with associated FC than with those without FC (90% vs 58%). Neither FNA technique nor anatomic site affected the likelihood of obtaining an adequate sample for FC analysis and/or rendering a definitive morphologic or unequivocal FC diagnosis. Likewise, tumor subtype did not affect the likelihood of acquiring enough cells for FC analysis, but occasionally resulted in equivocal FC diagnoses or discordant FNA and FC diagnoses. Aggressive B-cell lymphomas and Hodgkin lymphomas were significantly less likely to be detected by FC as compared to low-grade B-cell lymphomas. Discrepancies between FNA and FC diagnoses occurred in 13% of cases. The majority of discrepancies (78%) included FC false negatives, while only 22% of cases had atypical or positive FC with negative FNA. CONCLUSIONS FNA with associated FC is a powerful diagnostic technique; however, lymphoma subtype may affect diagnostic sensitivity by FC, and therefore, discordant FNA and FC results should be interpreted with caution.

Objective Morphologic diagnosis and grading of anal squamous intraepithelial lesions (ASILs) are challenging. In this study, we investigated interobserver variability and p16 utility in accurately grading anal SIL. Materials and methods Six pathologists evaluated the degree of SIL on hematoxylin and eosin slides from 146 anal biopsies, followed by the review of both p16 and hematoxylin and eosin slides in cases where p16 was previously performed. κ was calculated in the following 4 ways: (A) 4-tiered diagnosis (negative for SIL [NSIL], anal intraepithelial neoplasia [AIN 1, AIN 2, AIN 3]); (B) 3-tiered diagnosis (NSIL and AIN 1 [pooled], AIN 2, AIN 3); (A) 3-tiered diagnosis (NSIL, low-grade SIL, high-grade SIL [HSIL]); and (D) 2-tiered diagnosis (no HSIL, HSIL). Results There is only moderate agreement with a 4-tiered diagnosis with or without p16 (κ = 0.48-0.57). There is substantial agreement when AIN 2 and AIN 3 are pooled as HSIL in cases with or without p16 review (κ = 0.71-0.78). There is almost perfect agreement with a 2-tiered diagnosis of negative for HSIL and HSIL both in cases where p16 was used and where p16 was not required, with the best agreement for a 2-tiered diagnosis with concurrent p16 review. Conclusions This study highlights the importance of a judicious use of p16 for diagnosis. When there is no need for p16 by the Lower Anogenital Squamous Terminology guidelines, interobserver agreement was substantial to almost perfect with a 2-tiered diagnosis. However, when its use is indicated but it is not performed or reviewed, the agreement is much lower even with a 2-tiered diagnosis. Rational use of p16 will ensure diagnostic accuracy and the best possible patient care.

Simple Summary We presented a machine learning approach for accurate quantification of nuclear morphometrics and differential diagnosis of primary intestinal T-cell lymphomas. The human interpretable machine learning approach can be easily applied to other lymphomas and potentially even broader disease categories. This approach not only brings deeper insights into lymphoma phenotypes, but also paves the way for future discoveries concerning their relationship with disease classification and outcome. Abstract The aim of this study was to investigate the feasibility of using machine learning techniques based on morphological features in classifying two subtypes of primary intestinal T-cell lymphomas (PITLs) defined according to the WHO criteria: monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) versus intestinal T-cell lymphoma, not otherwise specified (ITCL-NOS), which is considered a major challenge for pathological diagnosis. A total of 40 histopathological whole-slide images (WSIs) from 40 surgically resected PITL cases were used as the dataset for model training and testing. A deep neural network was trained to detect and segment the nuclei of lymphocytes. Quantitative nuclear morphometrics were further computed from these predicted contours. A decision-tree-based machine learning algorithm, XGBoost, was then trained to classify PITL cases into two disease subtypes using these nuclear morphometric features. The deep neural network achieved an average precision of 0.881 in the cell segmentation work. In terms of classifying MEITL versus ITCL-NOS, the XGBoost model achieved an area under receiver operating characteristic curve (AUC) of 0.966. Our research demonstrated an accurate, human-interpretable approach to using machine learning algorithms for reducing the high dimensionality of image features and classifying T cell lymphomas that present challenges in morphologic diagnosis. The quantitative nuclear morphometric features may lead to further discoveries concerning the relationship between cellular phenotype and disease status.

p16 is the most useful diagnostic marker for human papillomavirus (HPV)-associated anogenital lesions. In the cervix, the pattern of p16 immunoreactivity generally correlates with lesion severity. p16 expression in anal intraepithelial neoplasia (AIN) is far less studied. Whether such correlation holds true has to be determined. We correlated the degree and pattern of p16 immunohistochemistry (IHC) results with morphologic diagnoses of 1000 anal squamous and transitional zone biopsy specimens. Using the Lower Anogenital Squamous Terminology criteria, p16 IHC results were classified as block staining, partial staining, or negative. Among 150 samples without morphologic evidence of AIN, p16 was negative in 85% and partial staining in 15%. AIN 1 (n=400) revealed diverse results: 28% negative, 35% partial, and 37% block staining. Among AIN 2 (n=298), 89% were block, 9% partial staining, and 2% negative. AIN 3 (n=152) revealed block (95%) or partial staining (5%). For the detection of AIN 2/3, p16 block staining yielded 91% sensitivity, 73% specificity, 80% positive predictive value, 91% negative predictive value, and a Youden Index of 0.64. Combining block staining and partial staining slightly increased sensitivity (99%) and negative predictive value (98%), but significantly decreased specificity (43%), positive predictive value (59%) and Youden Index (0.42, P

In this era of targeted therapy, traditional reporting of acute leukemia by morphology using French-American-British (FAB) system of classification has limited uses due to lack of standardization and use in risk stratification. Flow cytometry (FCM), cytogenetics, and molecular testing drive the therapeutic decision. However, the lack of high-end testing at all health care strata leaves a general pathologist in a quandary. This study aimed at documenting the leukemia-associated immunophenotype (LAIP) specific for morphologic (FAB) subclasses of acute leukemia (AL). A retrospective case record-based study was carried out including 100 cases of de novo acute leukemia over 1 year to study the association of FCM immunophenotype profile with morphologic FAB classification of acute leukemia. Fourteen cases (14%) were diagnosed as acute leukemia—unclassified by morphology which were accurately classified by FCM into B cell acute lymphoblastic leukemia (ALL) (6), T cell ALL (3), acute myeloid leukemia (AML) (4), and mixed phenotype acute leukemia (MPAL) (1). FCM also differentiated Pre B cell ALL from Burkitt lymphoma, subclassified T cell ALL into thymic categories, diagnosed MPAL, and identified blasts with monocytic differentiation which were not detected by morphology. Although morphologic FAB diagnosis is still widely used to classify acute leukemia, it is imperative that FCM should be used for accurate leukemia diagnosis.

The cytologic evaluation of serous effusions may be challenging for a number of reasons. Distinction of benign, reactive conditions from malignancy represents the main focus when examining these specimens. The morphologic diagnosis of malignancy may be difficult due to the relative paucity of abnormal cells. In other situations, cellularity is not an issue, but the ability to confidently identify a second, foreign (i.e., tumor) population within a background mesothelial cells on the basis of cytomorphologic features alone may pose problems. Cases with definitive morphologic evidence of malignancy may require additional studies in order to determine the tumor subtype and, in the case of carcinoma, the primary site of origin. Cases in which a definitive and precise diagnosis of malignancy is made may be optimal candidates for further molecular testing in order to gain prognostic information and guide personal therapeutic decisions. Finally, while an inflammatory or infectious condition can be suggested on the basis of cellular components and associated background elements, the identification of causative agent(s) may be difficult without additional studies. In all of these situations, the use of ancillary studies and techniques is critical; their utility and appropriate application are the subject of this review.

In fine-needle aspirations (FNA) of thyroid, Hürthle cells can be found in a broad spectrum of lesions, ranging from non-neoplastic conditions to aggressive malignant tumors. Recognize them morphologically, frequently represents a challenging for an adequately diagnosis and are associated with a significant interobserver variability. Although the limitations of the morphologic diagnosis still exist, the interpretation of the context where the cells appear and the recent advances in the molecular knowledge of Hürthle cells tumors are contributing for a more precise diagnosis. This review aims to describe the cytology aspects of all Hürthle cells neoplastic and non-neoplastic thyroid lesions, focusing on the differential diagnosis and reporting according to The Bethesda System for Reporting Thyroid Cytology (TBSRTC). New entities according to the latest World Health Organization (WHO) classification are included, as well as an update of the current molecular data.

Acute myeloid leukemia (AML) is defined by the presence of ≥ 20% myeloblasts in the blood or bone marrow. Spontaneous remission (SR) of AML is a rare event, with few cases described in the literature. SR is generally associated with recovery from an infectious or immunologic process, and more recently possibly with clonal hematopoiesis. We review the literature and assess the trends associated with SR, and report a new case of a 58-year-old man with a morphologic diagnosis of AML associated with a severe gastrointestinal (GI) tract infection. The patient had an NF1 variant that was previously unreported in AML as the only clonal abnormality. After treatment of the infection, the increased blast population subsided with no leukemia-directed therapy, and the patient has remained in a continuous, spontaneous complete remission for > 2 years.

Aim. To discuss controversial aspects of diagnosis and surgical treatment of suspected ductal cholangiocarcinoma using several clinical cases. Material and Methods. Three cases of radically-operated patients with ductal cholangiocarcinoma are presented here. Postoperative morphologic examination did not confirm the diagnosis in all these cases. Conclusion. A choice of surgical volume should not be based only on morphologic data, especially on preoperative data. Preoperative morphologic diagnosis is not always possible. Significant increase of CA19-9 level allows to consider an availability of cholangiocarcinoma but its normal values don’t exclude tumor either. It is necessary to take into account the functional state of liver and morphologic changes of removed liver lobe. Pancreatic head sparing surgery seems to be important in case of distal cholangiocarcinoma that will directly effect surgery volume. Therefore, preoperative morphologic diagnosis is of great value. Adequate and good-quality radical surgery for suspected Klatskin’s tumor or cholangiocarcinoma has main indisputable advantage. It allows to cure a patient with benign disease and gives a chance for a positive long-term prognosis in case of cancer. Such approach should be individual and used in specialized centres.

While most melanomas can be distinguished from nevi by histopathology, the histology is ambiguous for some melanocytic tumors, contributing to diagnostic uncertainty. Therefore molecular assays, including FISH or SNP array, and more recently a gene expression test (myPath, Myriad Genetics) have been proposed to aid in the work-up of ambiguous tumors. Two hundred and sixty-eight prospectively submitted cases were gathered, with the goal of comparing the myPath assay to morphologic diagnosis in (1) morphologically unequivocal cases (198), and to morphologic diagnosis and FISH in (2) morphologically ambiguous cases (70). Melanoma FISH was performed using probes for 6p25, 6q23, 11q13, Cep6, 9p21, and Cep9 and scored according to established criteria. The myPath assay was scored by the manufacturer as benign, indeterminate, or malignant. In the unequivocal group, myPath assay showed 75% agreement with morphologic diagnosis, with 67% sensitivity and 81% specificity. In the ambiguous group, FISH and myPath showed 69% inter-test agreement. For these cases agreement with histopathologic interpretation was 84% for FISH and 74% for myPath. Sensitivity and specificity of FISH was 61 and 100%, 50 and 93% for myPath, respectively. Cases from both groups in which myPath was discordant with either morphologic diagnosis and/or FISH (81/268 cases), were submitted for evaluation by two experienced dermatopathologist and also by SNP-array. SNP-array results correlated better than FISH, which correlated better than myPath, with the morphologic interpretation. Our findings document that molecular diagnostics show good correlation with consensus diagnoses, but discordant results occur, and vary in level of correlation with consensus interpretations. Studies with long-term outcomes data within specific ambiguous lesion subsets are required to establish the accuracy of this test, as each molecular diagnostic technique has limitations based on both lack of clinical outcomes data in ambiguous melanocytic tumors and in terms of their sensitivity and specificity in melanocytic lesion subtypes.

Context: The ordinary morphologic diagnosis of ALL by pathologists depends on examining patient peripheral blood together with the bone marrow blood films. However, this manual aspect for diagnosis is susceptible to discrepancies. We have a newly introduced technology that allows for overcoming individual variations in the diagnosis of ALL, so-named machine learning, depending on a complex preprogrammed convolutional network matrix. Objectives: Challenging machine-aided systems, which utilize microscopic blood film images to recognize and diagnose ALL based on a preprogrammed deep convolutional neural network (CNN), i.e., machine learning algorithms. Materials and Methods: We collected a dataset of images composed of PB & BM smear images of two classes; ALL and normal control blood. We analyzed 192 samples of digital images: 96 images of patients with ALL and 96 images of healthy normal controls. For each smear sample, we collected the results of clinical data (clinical history and examination) and laboratory data (morphological, cytochemical, and immunophenotyping assessment). We challenged seven types of CNN models: Alexnet, VGG16, VGG19, GoogLeNet, ResNet50, ResNet101, and Inception-v3 to diagnose ALL. Results: Comparing the ability of 7 models to diagnose ALL revealed that the Alexnet had the lowest accuracy of 95.51%, followed by VGG16 at 92.13% and VGG19 at 93.83%, whilst the Inception-v3 had a promising highest accuracy of 99.98%.and was able to detect almost all ALL cases. Conclusion: The statistical measures of the Inception-v3 performance revealed promising results. The sensitivity, specificity, and accuracy of Inception-v3 reached 99.98% for detection of ALL.

Ewing sarcoma is an aggressive neoplasm of pediatric and adolescent patients. Immunohistochemistry (IHC) can be used to support the morphologic diagnosis of Ewing sarcoma family of tumors (ESFT) in a convincing clinical/radiological context. Although neither NKX2.2 nor CD99 alone are entirely specific, when combined, the diagnostic specificity is high. The aim of the present study was to investigate the IHC expression of NKX2.2, ETV4 and BCOR in a large series of genetically confirmed ESFT. The results for CD99 and CAV-1 immunoreactivity, and the histological and fusion gene subtypes were retrieved from our previous study. NKX2.2 demonstrated moderate or strong nuclear positivity in 91.2% of the tumors. The staining intensity was heterogeneous. Many of the ESFT with negative NKX2.2 immunoreactivity were in bone. Strong/moderate ETV4 nuclear expression was detected in two small round cell tumors, both were negative for NKX2.2. No relationships could be found between expression of NKX2.2 and the histological subgroups or ESFT gene fusion subtypes. BCOR was negative in all ESFT. In conclusion, NKX2.2, ETV4 and BCOR IHC may be helpful in daily practice for distinguishing ESFT from CIC or BCOR-associated sarcomas, especially in hospitals without access to molecular assays. In addition, the combination of strong CD99 membranous positivity and nuclear NKX2.2 positivity seems to be very reliable for ESFT diagnosis in an appropriate clinicoradiological setting. So far no antibody is entirely specific for ESFT diagnosis, and the IHC or molecular results in round cell tumors of bone may be strongly influenced by decalcification processes.

Pleomorphic sarcomas are a group including some of poorly differentiated mesenchymal malignancies, which differ in morphology, molecular and biological properties and clinical outcomes. They are relatively rare tumors comprising, by different assessments, 5 to 7% of all mesenchymal malignancies. The tumors affect soft tissues of the limbs, body, retroperitoneal space and mediastinum. The morphologic substrate of pleomorphic sarcomas is polymorphic tumor cells of fibroblast cell lines, smooth myocytes, rhabdomyoblasts, Schwann cells, etc. Accuracy of morphologic diagnosis of pleomorphic sarcomas ranges between 13 to 26%. In practice it means that histological type of pleomorphic sarcoma is correctly defined only in a quarter of patients. Meanwhile, the importance of defining the histological type before starting the treatment is explained by the fact, that accurate histological and simultaneous molecular characteristics of pleomorphic sarcomas points the way to selective therapy of such tumors. The article presents the results of our observation of a 27-year-old patient with pleomorphic cardiac rhabdomyosarcoma. In this case cardiac tumor, first defined during echocardiography, is one of metastases of pleomorphic rhabdomyosarcoma of neck soft tissues. But at retrospective analysis its primary nature cannot be ruled out. The difficulties of morphologic diagnosis occurring during tumor verification are objective as the diversity of tissues - sources of pleomorphic sarcomas - creates extremely complex histological presentation and exceptionally embarrasses defining the histogenesis of the tumor.

Collapsing glomerulopathy (CGP) is a pattern of kidney injury seen on renal biopsy with multiple associations and etiologies. It is most commonly described in African-Americans and others with recent African ancestry. The disease is rapidly progressive and often presents with abrupt onset of renal failure and nephrotic-range proteinuria. Since its description 30 years ago, this entity has transformed from a morphologic diagnosis typically seen in the setting of HIV infection to a complicated diagnosis with numerous etiologies, many of which are associated with underlying apolipoprotein L1 (APOL1)-risk variants or other genetic disorders. We review the evolution of CGP, and its history and proposed pathomechanisms. We also present the disease spectrum from our experience with emphasis on recognizing the lesion, distinguishing from mimics and linking the histopathological pattern to a specific cause. Our understanding continues to evolve as clinicians and scientists work toward a more complete understanding of the molecular pathways of injury in this disease and how these might be disrupted for therapeutic purposes. Much still remains to be discovered in CGP as the molecular underpinnings leading to disease are still not completely understood and no effective treatment exists despite the high morbidity. Based on this rapid evolution, CGP is a modern template of how we diagnose and think about kidney disease. The story of CGP represents the current shift in nephrology and nephropathology from morphology-alone-based diagnosis to a comprehensive approach including molecular diagnostics. We believe this new, holistic approach will lead to pathogenesis-centered diagnoses that will help to individualize risk stratification and treatment protocols.

Clinical summary: A 13-year-old, spayed Devon Rex with unilateral digital flexor musculotendinous contracture of the forelimb was treated by surgical tenotomy. The condition improved transiently, but recurred rapidly and became bilateral. Histopathologic analysis of necropsy tissues resulted in a morphologic diagnosis of fibromyositis of the antebrachial muscles causing contracture and flexural deformity of the carpi and phalanges of both thoracic limbs. A search for similar cases yielded the clinical notes of a second cat, a 10-year-old, spayed Devon Rex, also with bilateral disease. This second case responded well to surgical tenotomy but tissue biopsies were not obtained to permit microscopic assessment of the underlying pathologic process. Relevance and novel information: Acquired and permanent contracture of the digital flexor muscles and/or tendons of the forelimbs is a rare and poorly described condition of cats. The very limited number of documented cases describing disease affecting one or more digits (but not the carpus) infers a causal link with onychectomy, but reported histopathologic changes have been limited to the tendons. The two cases described in this report suffered contracture of the carpus and all digits bilaterally, one without previous onychectomy and the other 9 years after onychectomy. There were novel histopathologic findings in the muscles of the one case for which biopsy material was available. Information gained from these two cases provides a new perspective for the investigation and treatment of future cases. Specifically, consideration should be given to an underlying immune-mediated myopathic process and a possible genetic predisposition in the Devon Rex breed. Currently, the poorly understood etiopathogenesis hinders our ability to definitively recommend treatment options, which might include corticosteroids and other forms of immunosuppressive therapy.

Conflicting data have been published on the prognostic significance of tumor necrosis in papillary renal cell carcinoma (PRCC). Although the presence of necrosis is generally considered an adverse prognostic feature in PRCC, we report a cohort of 10 morphologically distinct cystic and extensively necrotic PRCC with favorable biological behavior. Ten cases of type 1 PRCC with a uniform morphologic pattern were selected from the 19 500 renal tumors, of which 1311 were PRCCs in our registry. We focused on precise morphologic diagnosis supported by immunohistochemical and molecular-genetic analysis. Patients included 8 men and 2 women with an age range of 32-85 years (mean, 62.6 years). Tumor size ranged from 6 to 14 cm (mean, 9.4 cm). Follow-up data were available in 7 patients, ranging from 0.5 to 14 years (mean, 4 years). All tumors were spherical, cystic, and circumscribed by a thick fibrous capsule, filled with hemorrhagic/necrotic contents. Limited viable neoplastic tissue was present only as a thin rim in the inner surface of the cyst wall, consistent with type 1 PRCC. All cases were positive for AMACR, OSCAR, CAM 5.2, HIF-2, and vimentin. Chromosome 7 and 17 polysomy was found in 5 of 9 analyzable cases, 2 cases demonstrated chromosome 7 and 17 disomy, and 1 case showed only chromosome 17 polysomy. Loss of chromosome Y was found in 5 cases, including 1 case with disomic chromosomes 7 and 17. No VHL gene abnormalities were found. Papillary renal cell carcinoma type 1 can present as a large hemorrhagic/necrotic unicystic lesion with a thick fibroleiomyomatous capsule. Most cases showed a chromosomal numerical aberration pattern characteristic of PRCC. All tumors followed a nonaggressive clinical course. Large liquefactive necrosis should not necessarily be considered an adverse prognostic feature, particularly in a subset of type 1 PRCC with unilocular cysts filled with necrotic/hemorrhagic material.

The article describes the most pertinent techniques for morphologic diagnosis of tuberculosis incorporating the related problems encountered by practicing pathologists including frequently meet co-infection with HIV, increase of non-tuberculous mycobacterioses and detection of mycobacteria possessing atypical properties presented by coccus and branching forms. The detection of causative agents located extracellular is discussed as well as their potential ability to form biofilms.

Context.— Fine-needle aspiration cytology (FNAC) of pulmonary nodules is usually guided by computed tomography (CT), whereas ultrasonography (US) is generally considered not applicable for such purposes. Objective.— To evaluate the clinical applicability and diagnostic utility of US-guided transthoracic FNAC of peripheral pulmonary nodules. Design.— Ultrasonography-guided transthoracic FNAC was obtained from 40 selected patients with peripheral, subpleural, and paravertebral pulmonary nodules. Air-dried and Diff-Quik–stained smears were used for rapid on-site evaluation; additional smears were alcohol fixed for Papanicolaou staining. Cell blocks were set up for immunocytochemical and molecular studies; in 2 cases, a flow cytometry evaluation was also performed. The series was compared to 40 CT-guided pulmonary FNAC samples from patients with pleural, peripheral, and paravertebral pulmonary nodules, to evaluate differences in terms of diagnostic rate, time of execution, safety, and cost. Results.— The US-guided FNAC samples had results that were adequate and representative in 95% of cases. No significant differences were observed between the 2 groups in terms of diagnostic rate, number of passes, and cellularity of both smears and cell blocks. The mean time needed for the execution of US-guided FNAC was 13.1 minutes, whereas the mean time for CT-guided FNAC was 23.6 minutes. Thus, US-guided FNAC was significantly more rapid than CT-guided pulmonary FNAC. Because pneumothorax occurred in 1 individual who underwent US-guided FNAC and in 9 who underwent CT-guided FNAC, we might conclude that US-guided FNAC is a significantly safer procedure. Finally, comparing the costs of both procedures, US-guided FNAC is less expensive. Conclusions.— Our experience showed an elevated clinical applicability and diagnostic utility of US-guided transthoracic FNAC for selected pulmonary nodules.

For decades, histopathology with routine hematoxylin and eosin staining has been and remains the gold standard for reaching a morphologic diagnosis in tissue samples from humans and veterinary species. However, within the past decade, there has been exponential growth in advanced techniques for in situ tissue biomarker imaging that bridge the divide between anatomic and molecular pathology. It is now possible to simultaneously observe localization and expression magnitude of multiple protein, nucleic acid, and molecular targets in tissue sections and apply machine learning to synthesize vast, image-derived datasets. As these technologies become more sophisticated and widely available, a team-science approach involving subspecialists with medical, engineering, and physics backgrounds is critical to upholding quality and validity in studies generating these data. The purpose of this manuscript is to detail the scientific premise, tools and training, quality control, and data collection and analysis considerations needed for the most prominent advanced imaging technologies currently applied in tissue sections: immunofluorescence, in situ hybridization, laser capture microdissection, matrix-assisted laser desorption ionization imaging mass spectrometry, and spectroscopic/optical methods. We conclude with a brief overview of future directions for ex vivo and in vivo imaging techniques.

Immunohistochemistry may be a very useful adjunct to morphologic diagnosis in many areas of surgical pathology, including genitourinary pathology. In this review, we address common diagnostic dilemmas where immunophenotypic analysis may be utilized and we highlight pitfalls specific to each scenario. For prostate, we review the diagnosis of limited prostatic adenocarcinoma and the distinction of high-grade prostatic adenocarcinoma from urothelial carcinoma. We also cover markers of urothelial lineage in the diagnosis of metastatic carcinoma of unknown primary site. In the kidney, distinction of poorly differentiated renal cell carcinoma from urothelial carcinoma and epithelioid angiomyolipoma, adjuncts to the recognition of hereditary renal neoplasia, and the diagnosis of metastatic renal cell carcinoma are discussed. Finally, for testis we address distinction of germ cell tumors from sex cord-stromal tumors, as well as the diagnosis of metastatic germ cell tumors.

Despite the rapid development of molecular markers during the last years, the morphology of blood and bone marrow cells still keeps the crucial role for diagnosis and subclassification of the different subtypes of myelodysplastic syndromes (MDS), as recently confirmed by the new 2016 WHO classification [1]. Nevertheless, morphologic diagnosis is not always self-evident. While increased blast cells are often in-line with advanced MDS subtypes, early forms with mild morphological changes can represent a diagnostic challenge. Especially in these cases, morphologic experience is crucial but should be embedded into further information on disease history, exclusion of other underlying diseases, as well as additional cytogenetic, molecular, and immunophenotypic data to confirm diagnosis of MDS.

Soft tissue sarcomas represent a heterogeneous group of rare malignancies exhibiting mesenchymal differentiation with an overall incidence of around 5/100,000/year. Rarity and morphologic heterogeneity significantly affect diagnostic accuracy; therefore, expertise can be achieved only through access to large number of cases. Soft tissue sarcomas are currently classified on the basis of the 2013 WHO classification of soft tissue tumors that integrate conventional morphology with immunohistochemistry and molecular genetics. The morphologic diagnosis of sarcoma relies on the evaluation as well as the integration of four main features: the shape of the neoplastic cells; the pattern of growth; the quality of the background; the architecture of the vascular network. Immunohistochemical characterization plays a key role in the diagnostic workup of soft tissue sarcomas. The majority of classic differentiation markers tend to show good sensitivity, however, associated with rather limited specificity, making interpretation in context with morphology mandatory. Molecular genetics is increasingly used for diagnostic purposes to distinguish specific subtypes of sarcomas, to support diagnosis in non-canonical clinical presentations and also to distinguish true sarcomas from benign mimickers. With many exceptions, histologic typing does not provide sufficient information for predicting the clinical course of the disease and, therefore, grading systems based on histological parameters were introduced to provide a more accurate estimation of the degree of malignancy of tumors. The three-tiered system devised by the French Federation of Cancer Centers Sarcoma Group (FNCLCC) systems is widely adopted; however, several limitations exist that have led to the development of prognostic nomograms that incorporate the specific histotype as one of the relevant parameters.

Ambiguous genitalia is a morphologic diagnosis, with various underlying genetic and hormonal etiologies. Because of the complex genetic, hormonal, physical, and social factors involved, determination of fetal sex in cases of ambiguous genitalia is best done postnatally, incorporating an array of clinical consultants. Congenital adrenal hyperplasia (CAH) is the most common cause of ambiguous genitalia; timely diagnosis in the postnatal period is important because of the life-threatening consequences of the classic salt-wasting form. In cases of ambiguous genitalia, invasive diagnosis with chorionic villus sampling (CVS) or amniocentesis can be helpful in reconciling ultrasound (US) findings, determining genetic sex, and diagnosing CAH. Karyotypic results do not always determine sex assignment, given the complex hormonal and social issues involved in sex determination.

Background Angioleiomyoma (ALM) is a benign neoplasm that originates from vascular smooth muscle. It is extremely rare in oral cavity. The objective of this study was to evaluate the clinicopathological and immunohistochemical characteristics of all oral angioleiomyomas registered in a Center of Diagnosis of Oral Diseases from 1959 to 2017. Material and Methods Slides from 14 cases of ALM stained with hematoxylin and eosin (H&E) were analyzed to confirm the diagnosis. Moreover, an immunohistochemical panel with alpha-smooth muscle actin (alpha-SMA), desmin, AE1/AE3, CD68, S-100, and CD34 antibodies was performed to evaluate semi-quantitatively the positive cells. Results ALM correspond to 0.08% of all benign oral tumors analyzed during the 57-year period. The mean age of the patients was 45 years with a predilection to males (58%). The most frequently reported site was lips (50%). Microscopic analysis on H&E sections revealed similar pattern in all cases, showing well-circumscribed and encapsulated tumors, characterized by a proliferation of smooth muscle cells and wide vascular spaces of varying sizes. The predominant immuno profiles were: alpha-smooth muscle actin (alpha-SMA) positive (strong immunoreactivity); positive variable pattern for desmin, negative immunoprofile for AE1/AE3, CD68, and S-100. The endothelial cells of vascular spaces were CD34+. Conclusions Based on the results, the alpha-SM actin can be elected as a good marker for angioleiomyomas and can help the confirmation of the morphologic diagnosis of this lesion. Key words:Angioleiomyoma, Alpha-SMA, vascular smooth muscle.

An increasing spectrum and number of opportunistic fungal pathogens have been reported to cause disease in humans over the past decade. Disseminated phaeohyphomycoses caused by rare dematiaceous molds in immunocompromised patients have a high mortality rate and are increasingly reported in the literature. Early diagnosis of disseminated phaehyphomycosis is critical especially in neutropenic patients but can be hindered by the low sensitivity of fungal blood cultures and low clinical suspicion. Cutaneous manifestations are often the earliest sign of disease and conducting a thorough skin exam in febrile neutropenic patients can lead to more rapid diagnosis and initiation of treatment. PCR amplification and sequencing of mold RNA extracted from paraffin-embedded tissue can be useful for diagnosing rare fungal infections when negative fungal cultures preclude morphologic diagnosis. Effective treatment for disseminated phaehyphomycosis is lacking and there is a need to report experiences with the use of newer antifungals.

Endoscopic ultrasound (EUS) and its guided fine needle aspiration (FNA) has changed paradigm of managing patients with pancreatic cancer. Morphologic diagnosis of pancreatic cancer on limited FNA material is inherently difficult. Furthermore, EUS-FNA samples are often bloody and are admixed with gastrointestinal tract epithelium, which adds to the complexity in interpretation. Indeterminate diagnoses on pancreatic FNA often delays definitive therapy for patients. In such instances, ancillary may further aid in supporting or confirming diagnosis of malignancy. Several immunohistochemical markers such as mesothelin, S100A as well as SMAD4 have been investigated to support diagnosis of pancreatic carcinoma. Recently, multiprobe FISH analysis, microRNA and high throughput technologies are increasingly being used to provide precision medicine. Immunolabeling by markers such as Beta catenin, CD10 and E-Cadherin is increasingly being used to distinguish pancreatic endocrine neoplasm from solid pseudo papillary neoplasm. This review will highlight some of these ancillary studies helpful in diagnosis of solid pancreatic neoplasms.

The central nervous system (CNS) represents a highly complex immune-privileged organ with compartmentalization, regionspecific peculiarities and properties, as well as unusual cell types. It consists of highly specialized structures in various neuroanatomic regions, including gray and white matter areas, hippocampus, and circumventricular organs. Although gray and white matter can be easily distinguished in some areas, such as cerebrum, cerebellum, and spinal cord, this is not the case in other regions, such as the brainstem. In addition, CNS cells— such as astrocytes, neurons, oligodendrocytes, microglia, cerebellar external germinal cells, progenitor cells, and epiplexus cells—are present at varying quantities during embryogenesis and in the adult CNS as resident cells or during disease. Moreover, cellular plasticity during organogenesis and during disease initiation and progression represents a unique tissue-specific response. Furthermore, reaction patterns of cells—including chromatolysis of neurons, spheroid formation of axons, gemistocytic forms of astrocytes, and gitter cells of microglia/macrophages—will result in modified functions and morphology. This complexity of the CNS, with its neuroanatomic, neuropathologic, and neurologic implications, engenders the ‘‘myth of neuropathology,’’ in which the pathologic investigation of brain diseases is difficult, arcane, and frustrating. However, as with the skin and eye, the tissue-specific terminology should be considered a helpful manual to aid in precise thinking, instead of an insuperable hurdle. Most CNS structures and cell types can be identified with hematoxylin and eosin–stained sections, with assistance from a textbook on neuroanatomy and neuropathology. Factors causing CNS diseases include infectious pathogens, immune-mediated processes, gene defects, and noninfectious environmental factors resulting in inflammatory and degenerative changes. As for other body systems, pathologic evaluation often allows a morphologic diagnosis that, even if not indicating a specific diagnosis, suggests several causes or pathogeneses that form the basis for further investigation. This issue of Veterinary Pathology includes a series of 10 articles on degenerative and inflammatory CNS diseases due to various pathogens and noninfectious factors impressively displaying the plethora and diversity of causes, consequences, and reaction patterns of diseases of the nervous system.* This collection combats the myth of neuropathology by presenting a comprehensive insight into a range of morphologic CNS changes, including their interpretation, diagnosis, pathogenesis, and clinicopathologic correlation. The CNS is exposed to various environmental factors, including dietary imbalances, trauma, infectious pathogens, and toxins, or it may suffer from genetic conditions resulting in acute and chronic lesions. Most frequently, host cell– pathogen interaction is discussed under the assumption of a black-and-white response or, in other words, cell death or survival. However, especially in the CNS, cellular functions may remain impaired despite cell survival. A reduction of cellular ‘‘luxury functions,’’ defined as a loss of key elements that are essential to maintain organ homeostasis, may include reduced myelin production or disturbed axon formation. Although the overall stereotypic reaction pattern in the CNS allows a morphologic diagnosis, in most cases a definitive etiologic or pathogenetic interpretation may await further studies. In this respect, the study by Valberg et al on the pathogenesis of ‘‘shivers,’’ a progressive equine movement disorder, represents an excellent example of a thorough and successful analysis of a well-known but poorly understood disorder by combining neuropathology, immunohistochemistry, transmission microscopy, and neuroanatomy. This well-structured study sheds, for the first time, some light on the underlying mechanisms of this disease by revealing the existence of calretinin-negative, calbindin-positive, and glutamic acid decarboxylase–positive spheroids in Purkinje cell axons. The study by Ogawa et al on canine degenerative myelopathy—a progressive neurodegenerative disease frequently found in Pembroke Welsh Corgi dogs—and its clinical and pathologic similarities to human amyotrophic lateral sclerosis represents another example of modern and innovative neuropathology. The authors investigated abnormalities of autophagy, resulting in cell death through what is called type II programmed cell death, an important mechanism in this neurodegenerative disease. Their detailed study indicates that altered autophagosome degradation may result in LC3 and p62 accumulation in the degenerative myelopathy spinal cord. Both studies

The oral cavity is affected by a wide range of pathologic lesions, for which a morphologic diagnosis is required for proper management. Fine needle aspiration (FNA) is being increasingly used for preliminary diagnoses of such lesions. This is retrospective analysis of intraoral and oropharyngeal lesions diagnosed with FNAC over a period of 7 years. Out of total 55 cases, a definite diagnosis could be made on cytology in 50 cases (90.9 %). These 50 cases were further included in the study. Thirty cases were reported as non-neoplastic and 20 as neoplastic (11 benign and nine malignant). The diagnoses were made taking into account the background material (blood, mucin) and the predominant cells present (neutrophils, lymphoid cells, macrophages, hemosiderin laden macrophages, squamous cells, basaloid cells, spindle cells, giant cells). Histopathological diagnosis was available in 17 cases and corresponded with FNA diagnosis in 16 cases (94.12 %). No significant complications were seen in patients undergoing these FNAs. It can be concluded that FNA is a simple and rapid diagnostic test that can be useful for preliminary assessment of oral and oropharyngeal lesions.

Cervical low-grade squamous intraepithelial lesions (LSIL) (aka cervical intraepithelial neoplasia, grade 1 [CIN1]) can present considerable diagnostic challenges and are associated with poor interobserver reproducibility and overdiagnosis. Furthermore, ancillary studies such as p16 immunohistochemistry have shown little utility in resolving the LSIL versus negative/reactive differential. Human papillomavirus (HPV) RNA in situ hybridization (ISH) has shown promise as a diagnostic aid in this setting, but has not been studied in a large case series. We herein investigate high-risk and low-risk HPV RNA ISH in 126 cervical biopsies originally diagnosed as LSIL/CIN1 and compare HPV RNA ISH results to expert-adjudicated morphologic diagnosis to assess whether this assay can help routine cases attain the existing "gold standard" of morphologic consensus diagnosis. We also assess whether this criterion standard can be further improved by integration of HPV RNA ISH results. A consensus diagnosis of intraepithelial lesion (CIN1) was confirmed in 61% of cases, whereas 57% were HPV RNA. HPV-RNA positivity was 84% sensitive and 86% specific for an expert-adjudicated diagnosis of CIN1. Conversely, consensus diagnosis was 90% sensitive and 78% specific for the presence of HPV RNA. Integrating RNA ISH into morphologic review led to further reclassification of 10% of cases, resulting in 95% sensitivity and 98% specificity of HPV RNA ISH for a CIN1 diagnosis and 98% sensitivity and 92% specificity of CIN1 for the presence of HPV RNA. These findings suggest that judicious use of HPV RNA ISH can improve the accuracy of LSIL/CIN1 diagnosis for morphologically ambiguous cases.

Immunohistochemistry is a powerful and sensitive diagnostic tool for tumor diagnosis that requires high level of practical and theoretical knowledge. The precise tumor diagnosis begins with the adequate processing of tissue samples and includes the standardized stain technique, the optimal choice of diagnostic antibody panels, and ends with critical interpretation of stain results. In order to utilize all the benefits of immunohistochemistry and to minimize the possibilities of errors in tumor diagnosis, we recommend to consider the following points: 1. Initially it is important to remember that the careful histopathologic examination and clinical correlation remain the cornerstone of morphologic diagnosis. The immunoprofiling is to support or rule out one or more of possible differential diagnoses. 2. The laboratory of immunohistochemistry must be under the supervision of well-trained pathologist, highly skilled in methods and techniques of immunohistochemistry and has the necessary morphologic knowledge to do good and critical interpretation of immunohistochemical staining results. 3. The single marker immunohistochemistry is one of the most frequent sources of errors in tumor diagnosis. No single marker can be relied on exclusively. The use of adequate panel of antibodies helps to avoid misinterpretation; it is always advisable to confirm or exclude the diagnosis by two or more additional immunohistochemical markers. 4. Knowledge of the nature of targeted antigens is an important factor in the interpretation of the results. The following details are always to consider: The expression pattern of the antigens (nuclear, cytoplasmic, membranous, or extracellular). Stability of antigens during tissue processing. Optimal and standardized tissue fixation and processing and as a rule, bad H&E sections mean bad immunohistochemistry results. Histopathologists deal with neoplasia with heterogeneous cell populations with high potential of genotypic and phenotypic variations. The reason for the atypical antigen expression can be in the biology of the tumor or the nature of the antibodies used. 5. Features of any new antibody must be carefully studied, and the following parameters are to consider: Type of the antibody: polyclonal or monoclonal in addition to the clone type of the monoclonal antibody. Sensitivity and specificity of the antibody in addition to the recommended dilution of concentrated antibodies. Care must be exercised when using newly developed antibodies. New antibodies are often introduced as being highly specific, but after prolonged use or testing on tissue microarrays, many of them prove to be less specific. The specificity and sensitivity of used detection system. 6. The standardization of the immunohistochemical staining method is one of the essential factors for correct interpretation of stain results. Positive and negative controls are valuable for good interpretation. 7. The interpretation and documentation of immunohistochemical results must be standardized. It is not enough to interpret the staining result as positive or negative. Quality and intensity of stain and staining pattern must be also considered and documented, and any conflicting results must be analyzed. Standardized reporting is very helpful in organizing the information to reach an accurate diagnosis. 8. Despite the high sensitivity of immunohistochemistry and the large number of available antibodies, immunohistochemistry—as any method—has its own limits. We should never force the diagnosis based on unclear or unspecific results. Some cases must be clarified or confirmed by additional methods. The detection of specific translocations or other genetic abnormalities associated with various types of neoplasia by molecular methods is an example where we need other methods to obtain a precise tumor diagnosis.

Morphologic dysplasia is an important factor in diagnosis of myelodysplastic syndrome (MDS). However, the role of dysplasia is changing as new molecular genetic and genomic technologies take a more prominent place in diagnosis. This review discusses the role of morphology in the diagnosis of MDS and its interactions with cytogenetic and molecular testing. Recent changes in diagnostic criteria have attempted to standardize approaches to morphologic diagnosis of MDS, recognizing significant inter-observer variability in assessment of dysplasia. Definitive correlates between cytogenetic/molecular and morphologic findings have been described in only a small set of cases. However, these genetic and morphologic tools do play a complementary role in the diagnosis of both MDS and other myeloid neoplasms. Diagnosis of MDS requires a multi-factorial approach, utilizing both traditional morphologic as well as newer molecular genetic techniques. Understanding these tools, and the interplay between them, is crucial in the modern diagnosis of myeloid neoplasms.

Congenital epidermolysis bullosa (CEB) is an extensive group of hereditary skin diseases, the differential diagnosis of which is a challenge due to the rarity of this pathology and the diversity of its clinical manifestations. The determination of the type of CEB makes it possible to estimate its prognosis and to facilitate a prenatal diagnosis.to optimize the morphological diagnosis of different types of CEB.28 skin biopsies from 14 patients with different types of CEB were investigated. The investigators performed routine histological examination of skin fragments taken from a bullous area and immunofluorescence antigen mapping using the indirect immunofluorescence test (IIFT) with antibodies against structural proteins of the dermal-epidermal junction (laminin α3, β3, and γ2 chains, keratins 5 and 14, types VII and XVII collagen, α6 and β4 integrin subunits, desmoplakin, plectin, kindlin-1, and plakophillin) of the apparently unaffected skin. The intact skin of healthy individuals, which had been obtained during cosmetic operations, was used as controls in IIFT.Immunofluorescence antigen mapping could determine the type of CEB in all cases and in 86% of cases identify the protein, the impaired production of which was responsible for the development of the disease.Immunofluorescence antigen mapping is an integral part of the comprehensive morphological diagnosis of CEB, acting as an intermediate between the morphological verification of CEB diagnosis and the targeted search for mutations by a molecular genetic method.Врожденный буллезный эпидермолиз (ВБЭ) представляет собой обширную группу наследственных заболеваний кожи, дифференциальная диагностика которых сложна в связи с редкостью данной патологии и многообразием ее клинических проявлений. Определение типа ВБЭ позволяет оценить прогноз заболевания и облегчить проведение пренатальной диагностики. Цель - оптимизация морфологической диагностики различных видов ВБЭ. Материал и методы. Исследовано 28 биоптатов кожи от 14 пациентов с различными видами ВБЭ. Проводилось рутинное гистологическое исследование фрагментов кожи, взятых в области пузыря, и иммунофлюоресцентное антигенное картирование с применением непрямой реакции иммунофлюоресценции (нРИФ) с антителами к структурным белкам дермо-эпидермального соединения (α3-, β3- и γ2-цепям ламинина, кератинам 5 и 14, коллагенам VII и XVII типов, α6- и β4-субъединицам интегрина, десмоплакину, плектину, киндлину-1, плакофилину) видимо непораженной кожи. В качестве контроля при проведении нРИФ использовалась неизмененная кожа здоровых лиц, полученная при косметических операциях. Результаты. Метод иммунофлюоресцентного антигенного картирования позволил во всех случаях установить тип ВБЭ и в 86% - белок, нарушение продукции которого обусловило развитие заболевания. Заключение. Иммунофлюоресцентное антигенное картирование является неотъемлемой частью комплексной морфологической диагностики ВБЭ, выступая промежуточным звеном между морфологическим подтверждением диагноза ВБЭ и таргетным поиском мутации молекулярно-генетическим методом.Врожденный буллезный эпидермолиз (ВБЭ) представляет собой обширную группу наследственных заболеваний кожи, дифференциальная диагностика которых сложна в связи с редкостью данной патологии и многообразием ее клинических проявлений. Определение типа ВБЭ позволяет оценить прогноз заболевания и облегчить проведение пренатальной диагностики. Цель — оптимизация морфологической диагностики различных видов ВБЭ. Материал и методы. Исследовано 28 биоптатов кожи от 14 пациентов с различными видами ВБЭ. Проводилось рутинное гистологическое исследование фрагментов кожи, взятых в области пузыря, и иммунофлюоресцентное антигенное картирование с применением непрямой реакции иммунофлюоресценции (нРИФ) с антителами к структурным белкам дермо-эпидермального соединения (α3-, β3- и γ2-цепям ламинина, кератинам 5 и 14, коллагенам VII и XVII типов, α6- и β4-субъединицам интегрина, десмоплакину, плектину, киндлину-1, плакофилину) видимо непораженной кожи. В качестве контроля при проведении нРИФ использовалась неизмененная кожа здоровых лиц, полученная при косметических операциях. Результаты. Метод иммунофлюоресцентного антигенного картирования позволил во всех случаях установить тип ВБЭ и в 86% — белок, нарушение продукции которого обусловило развитие заболевания. Заключение. Иммунофлюоресцентное антигенное картирование является неотъемлемой частью комплексной морфологической диагностики ВБЭ, выступая промежуточным звеном между морфологическим подтверждением диагноза ВБЭ и таргетным поиском мутации молекулярно-генетическим методом.

Eosinophilic esophagitis (EoE) is characterized clinically by dysphagia, chest pain, and food impaction, and morphologically by increased numbers of intraepithelial eosinophils and marked basal hyperplasia of the squamous mucosa. The consensus criteria for a diagnosis of EoE include the presence of ≥15 eosinophils/HPF in biopsies from both proximal and distal esophagus in the absence of other causes of esophageal eosinophilia, and the lack of clinical response to proton pump inhibitor therapy. Because of the variability in the distribution of intraepithelial eosinophils among biopsy fragments and the lack of standardized biopsy practices, we sought to determine the optimal number of esophageal biopsies from the mid and distal esophagus needed to reach the minimum morphologic criteria of ≥15 eosinophils/HPF.From 5 January 2009 to 26 September 2011, 771 patients were diagnosed with EoE at our institution. From that patient population, 102 sequential cases were chosen for further study, all of whom had biopsies taken from the mid and distal esophagus. Cases with only gastric mucosa present and biopsies taken from patients with a previous diagnosis of EoE were excluded. The original HE-stained slides were reviewed, and the number of biopsy fragments containing squamous mucosa was recorded. By using a × 40 objective and × 10 oculars (field diameter=0.52 mm, field area=0.21 mm(2)), the number of eosinophils per high power field (EOS/HPF) in up to three HPFs was counted in each biopsy fragment.The EOS/HPF were counted in 1,342 biopsy fragments. The number of biopsy fragments obtained from the mid esophagus ranged from 1 to 20 (mean 7; median 7) and those obtained from the distal esophagus ranged from 1 to 18 (mean 6; median 5). There was no significant difference between the mean number of EOS/HPF from the mid (26) and lower (25) esophagus or between the mean peak number of EOS/HPF from the mid (69.1) and lower (60.4) esophagus. The probability of one, four, five, and six biopsy fragments containing15 EOS/HPF was 0.63, 0.98, 0.99, and0.99, respectively.From these data, at least four biopsy fragments should be submitted from the mid and/or proximal esophagus to optimize the chances of a positive diagnosis of EoE in populations not known to have undergone previous proton pump inhibitor therapy. However, the yield is not increased beyond six biopsy fragments. In order to morphologically exclude a diagnosis of reflux esophagitis as the cause of intraepithelial eosinophilia, distal esophageal biopsies, if obtained, must be accompanied by more proximal biopsies (i.e., mid esophagus or higher).

A 20-yr-old African fur seal (Arctocephalus pusillus) presented with a slowly growing mass located on the dorsum at the level of the last thoracic vertebrae. The mass was hard, 10 cm in diameter, and not adherent to the underlying tissues. Multiple biopsies were collected for histopathology and revealed extensive areas of necrosis, small nodules of malignant mesenchymal proliferation with areas of chondroid metaplasia, and atypical cells in vessel walls. The morphologic diagnosis was suggestive of malignant mesenchymal neoplasia originating from the vascular wall. The mass was removed 1 mo later due to ulceration and infection. Histologically, based on the World Health Organization's classification of neoplastic processes in domestic animals, the tumor was consistent with malignant mesenchymoma. The margins of resection revealed the presence of neoplastic cells. Based on these results, the particular species involved, the high local invasiveness, and the high metastatic index of this malignant tumor in domestic mammals and humans, the prognosis was poor. The animal died 6 mo later with metatastic disease.

Gastrointestinal stromal tumor (GIST) is the most frequent mesenchymal tumor of the digestive tract, with 2/3 of cases occurring in the stomach. We report a case of GIST with rare angiosarcomatous transformation in a 59-year man who presented with a 50 lb unintended weight loss. Esophagogastroduodenoscopy demonstrated a 5 cm ulcerated mass in the body of the stomach. Morphologic diagnosis of high-grade …

High-grade neuroendocrine neoplasms (World Health Organization [WHO] G3) of the pancreas include both well-differentiated neuroendocrine tumor (WD-NET) and poorly differentiated neuroendocrine carcinoma (PD-NEC). According to the WHO classification scheme, the diagnosis of this group of tumors is based on both the histopathology of the tumor and the assessment of proliferation fraction. However, the former can be challenging due to the lack of well-defined histologic criteria, and the latter alone (ie, >20 mitoses/10 high-power fields or Ki67>20%) may not sufficiently distinguish WD-NETs from PD-NECs. Given the considerable differences in treatment strategies and clinical outcome, additional practical modalities are required to facilitate the accurate diagnosis of high-grade pancreatic neuroendocrine neoplasms. We examined 33 cases of WHO G3 neuroendocrine neoplasms of the pancreas and attempted to classify them into WD-NET, small cell PD-NEC (PD-NEC-SCC), and large cell PD-NEC (PD-NEC-LCC) or to designate them as "ambiguous" when an uncertain diagnosis was rendered by any of the observers or there was any disagreement in classification among the 3 observers. To simplify the interpretation, both PD-NEC-SCC and PD-NEC-LCC were considered together as PD-NECs in the final analysis. The initial approach was to assess microscopically a single morphologically challenging hematoxylin and eosin section from each case without the knowledge of Ki67 values, performed independently by 3 pathologists to assess the degree of diagnostic concordance, and then evaluate immunohistochemical staining for surrogate biomarkers of known genotypes of WD-NET and PD-NEC, respectively, and, lastly, complete a clinicopathologic review to establish a final definitive classification. Loss of DAXX or ATRX protein expression defined WD-NET, and abnormal p53, Rb, SMAD4 expression signified PD-NEC. When the chosen section displayed an element of WD histopathology, or other tumor sections contained WHO G1/G2 components, or there had been a prior established diagnosis of a primary WD-NET, the final diagnosis was rendered as a WD-NET with high-grade (G3) progression. If a component of conventional adenocarcinoma was present (in slides not seen in the initial review), the diagnosis was established as a combined adenocarcinoma and PD-NEC. All 3 pathologists agreed on the morphologic classification of 33% of the cases (6 WD-NET, 3 PD-NEC-SCC, and 2 PD-NEC-LCC), were conflicted on 2 cases between PD-NEC-SCC and PD-NEC-LCC, and disagreed or were uncertain on the classification for the remaining 20 cases (61%), which were therefore categorized as ambiguous. In the group of cases in which all pathologists agreed on the classification, the 6 WD-NET cases had either loss of DAXX or ATRX or had evidence of a WD-NET based on additional or prior pathology slides. The 7 PD-NEC cases had abnormal expression of p53, Rb, and/or SMAD4 or a coexisting adenocarcinoma. In the ambiguous group (n=20), 14 cases were established as WD-NETs, based upon loss of DAXX or ATRX in 7 cases and additional pathology evidence of high-grade progression from WD-NET in the other 7 cases; 5 cases were established as PD-NEC based upon abnormal expression of p53, Rb, and/or SMAD4; 1 case remained undetermined with normal expression of all markers and no evidence of entity-defining histologic findings in other slides. On the basis of the final pathologic classifications, the disease-specific survival was 75 and 11 months for the WD-NET and PD-NEC groups, respectively. Thus, we conclude that morphologic diagnosis of high-grade pancreatic neuroendocrine neoplasms is challenging, especially when limited pathologic materials are available, and necessitates better defined criteria. The analysis of both additional sections and prior material, along with an immunohistochemical evaluation, can facilitate accurate diagnosis in the majority of cases and guide the appropriate clinical management and prognosis.

Efforts at early detection of cancer have resulted in a sharp increase of overdiagnoses, ie, benign lesions being misinterpreted as malignant ones. Clinical overdiagnoses usually prompt a biopsy to be performed. The number of biopsies has risen dramatically, and the average time and diligence devoted to them have decreased. Biopsy specimens are often extremely small and sometimes crushed, leading to great difficulties in the assessment of histopathologic findings. In their fear not to overlook a malignant lesion, histopathologists confronted with an equivocal lesion tend to err on the malignant side, the results being histopathologic overdiagnoses and overtreatment. Epidemiologists have tried to counter those problems by cautioning against cancer screening and by inaugurating a change in nomenclature: the term "cancer" has been reserved for lesions likely to result in death, whereas earlier stages of the same process are referred to by different names emphasizing their ostensible innocuousness, and any diagnosis of a malignant neoplasm that does not produce symptoms or kill the patient is qualified as "overdiagnosis." In contrast to those suggestions that ignore biologic entities and sacrifice the foundations of morphologic diagnosis, measures are discussed that may help to overcome the problem of overdiagnosis and overtreatment in more substantial fashion.

Adenosarcoma (AS) is a rare biphasic neoplasm of the female genital tract characterized by an admixture of benign glandular and low-grade mesenchymal components. The classic low-power growth pattern is periglandular stromal proliferation accompanied by a variable degree of cytologic atypia and mitotic activity. However, as cytologic atypia is an objective criterion, and the number of mitotic figures required for diagnosis is inversely proportional to stromal cytologic atypia, there is a relatively wide variation in the decisive factors used among pathologists to diagnose an AS. Furthermore, the exact number of microscopic fields sufficient for diagnosis and/or the size of the fields adjusted to a specific microscope are not well established. These uncertainties are still an occasional source of misclassification of AS. Our study was conducted to explore the role of immunohistochemistry in the diagnosis of AS. Eight ASs were retrieved and compared with 14 endometrial polyps and 14 atypical polypoid adenomyomas. Immunohistochemical stains for Ki-67, caldesmon, smooth muscle actin, desmin, and CD10 were performed on all cases. All AS had a polypoid growth pattern with a variable increase in periglandular stromal cellularity and stromal nuclear atypia. The mitotic activity ranged from 1 to 15/10 high-power fields, and all AS demonstrated a distinct increase in Ki-67-positive nuclei in the periglandular zone compared with the adjacent stroma, regardless of the mitotic count. The Ki-67-labeling index in periglandular zones was ∼20% compared with

The orbit is affected by a wide range of pathologic lesions, for which a morphologic diagnosis is needed to allow adequate therapy. With increasing use of fine needle aspiration (FNA) in diagnostic pathology, the procedure has been applied for the diagnosis of space occupying lesions of the orbit. We present the cytomorphological diagnosis on orbital FNA in adult patients presenting with proptosis. Records of seven adult patients who had presented with proptosis and had undergone orbital FNA were retrieved and analysed. FNA was performed from the palpable mass in six cases and under ultrasound guidance in one case. No complication during or after FNA was reported in any of the cases. Histopathological diagnosis was available in 5 cases. Out of the 7 cases, 3 were non-neoplastic (2 inflammatory lesions, 1 reactive lymphoid hyperplasia) and 4 were neoplastic (2 primary tumors and 2 secondary involvement). Both the primary tumors were non Hodgkin's lymphoma (NHL) B-cell type. Metastases included one case of uterine sarcomatoid carcinoma and one case of secondary involvement by extension of olfactory neuroblastoma. In all the neoplastic cases, cytological diagnosis corresponded with the histopathological diagnosis. It can be concluded that cause of proptosis among adults are different from those among children and include secondary malignancies. FNA is a simple and important preliminary diagnostic modality in the assessment of adult proptosis prior to any surgical intervention. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.

Distinction of hydatidiform moles from nonmolar specimens and subclassification of hydatidiform moles as complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), or early CHM are important for both clinical practice and investigational studies. The risk of persistent gestational trophoblastic disease and hence, clinical management, differs for CHMs, PHMs, and nonmolar specimens. However, diagnosis based solely on morphology suffers from poor interobserver reproducibility and remains problematic even for experienced gynecologic pathologists. The unique genetic features of CHMs (androgenetic diploidy), PHMs (diandric triploidy), and nonmolar specimens (biparental diploidy) allow for certain molecular techniques, including immunohistochemical analysis of p57 expression (a paternally imprinted maternally expressed gene) and molecular genotyping, to refine the diagnosis of hydatidiform moles. Although p57 immunostaining alone can identify CHMs, which lack p57 expression because of the lack of maternal DNA, this analysis cannot distinguish PHMs from nonmolar specimens as both express p57 because of the presence of maternal DNA. Short tandem repeat genotyping, which can determine the parental source of polymorphic alleles, can distinguish among all of these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to rigorously diagnose CHMs, PHMs, and nonmolar specimens, respectively. An algorithmic approach using these techniques to refine morphologic diagnosis has been developed for routine practice. This review discusses current issues in the diagnosis of hydatidiform moles, including the limitations of morphologic diagnosis, the need for refined diagnosis to assure accurate ascertainment of risk of persistent gestational trophoblastic disease associated with the different subtypes of hydatidiform moles, the use of ancillary immunohistochemical and molecular techniques for providing such refined diagnosis, and problems that can be encountered with these techniques.

The application of standardized protocol by pathologists for handling, grossing, and assessing endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) specimens is critical for accurate diagnosis. To best analyze the specimen, several factors, such as maintenance of proper orientation, meticulous macroscopic examination, accurate mapping of the lesion, and appropriate morphologic diagnosis, must be considered. In Japan, general guidelines in the reporting of endoscopic, pathologic, and surgical findings of patients with gastrointestinal cancers have been used for more than 3 decades. More recently, similar universal guidelines have been developed, including the Paris and Vienna classifications, for clinical and pathologic findings, respectively. The WHO Classification of Tumors of the Digestive System (4th edition) can also provide a standardized method to classify pathologic diagnosis. These guidelines provide common terminology for the endoscopists, surgeons, and pathologists to communicate. The standard of practice for EMR and ESD reporting should always include the macroscopic diagnosis, size of the lesion, differentiation, associated findings (ie, gastritis), depth of invasion, presence of peptic ulcer or scar of a stomach lesion, margin status (horizontal and vertical), and lymphovascular/venous invasion because these features are relevant to prognosis and additional treatment decisions.

Distinction of hydatidiform moles from nonmolar specimens and subclassification of hydatidiform moles as complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), or early CHM are important for both clinical practice and investigational studies. The risk of persistent gestational t

Tumores mamários são comuns em cães, e constituem o neoplasma mais frequente em cadelas. Este estudo tem como objetivos principais estabelecer a prevalência dos tumores mamários, e dos diferentes tipos histológicos (neoplásicos e não-neoplásicos), diagnosticados em cães no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria (LPV-UFSM). Foram avaliados 1.304 protocolos de exames histopatológicos recebidos em 1990-2008 e 132 protocolos de necropsias realizadas em 2000-2008. Deles foram obtidos a raça, o sexo e a idade dos cães, a localização do tumor na cadeia mamária, o diagnóstico morfológico e a ocorrência de metástases. Nos protocolos de exame histopatológico, foram diagnosticados 1.495 tumores, considerando que alguns cães tinham mais de um tipo de tumor, sendo 1.465 neoplásicos e 30 não-neoplásicos. Dos neoplásicos, 390 (26,6%) eram benignos e 1.075 (73,3%) eram malignos, estabelecendo-se uma relação benigno: maligno de 1:2,75. Das 1.125 necropsias de cães realizadas em 2000-2008, 132 (11,6%) protocolos tinham descrições de tumor de mama, perfazendo 152 diagnósticos morfológicos, dos quais 150 eram neoplásicos e dois eram não-neoplásicos. Carcinoma simples foi o tipo histológico mais prevalente tanto em biópsias como em necropsias. Nas necropsias, foram observadas metástases para linfonodos em 39 casos (29,5%) e para órgãos distantes em 64 casos (53,3%).Mammary gland tumors are common in dogs and are the most common type of neoplasm of female dogs. The main purposes of this study were to establish the prevalence of the mammary gland tumors, as well as of its different histologic types (neoplastic and non-neoplastic), diagnosed in the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria. There were 1,304 biopsy reports of mammary gland tumors during 1990-2008 and 132 necropsy reports of dogs with mammary tumors in 2000-2008. Data about breed, gender, and age of dogs, tumor localization, morphologic diagnosis, and metastasis occurrence were analyzed. In the biopsy cases, 1,495 tumors were diagnosed, considering the presence of more than one type of tumor in some of the dogs. From those, 1,465 were neoplastic and 30 were non-neoplastic. Within the neoplasms, 390 (26.6%) were benign and 1,075 (73.3%) were malignant. The benign/malignant ratio was 1:2.75. During the years 2000-2008, 1,125 necropsies of dogs were performed, 132 (11.64%) of which with mammary gland tumors. There were 152 morphologic diagnoses, being 150 of neoplastic and two of non-neoplastic lesions. Simple carcinoma was the most prevalent histologic type, both among biopsy and necropsy cases. On necropsy cases, metastases to lymph nodes and distant organs were seen in 39 (29.5%) and 64 (53,3%) cases, respectively.