Optimizing schools of cytology: Discussions from the 2022 ASC/IAC Cytology Education Symposium, North American Strategies, and European Symbiosis.

This report highlights information and outcomes from the November 2022 ASC/IAC joint Cytology Education Symposium, an annual conference organized by the Cytology Programs Review Committee. The manuscript provides information on shared educational opportunities and practices for cytology students and other learners in anatomic pathology, discusses recruitment strategies for schools of cytology, conveys teaching resources, introduces perspectives on virtual microscopy and online learning, and transmits information about wellness of students in schools of cytology.

Low-grade adenosquamous carcinoma of the breast: a clinical, morphological and immunohistochemical analysis of 25 patients.

AIMS: Due to its rarity and non-specific clinical and pathological features, low-grade adenosquamous carcinoma (LGASC) of the breast continues to pose diagnostic challenges. Unlike other triple-negative breast carcinomas, LGASC tends to have an indolent clinical behaviour. It is essential to recognise this lesion for accurate diagnosis and appropriate management. METHODS AND RESULTS: Twenty-five cases of LGASC were identified in our archives and collaborating institutes. Cases of LGASC with dominant coexisting other type carcinomas were excluded. We studied the clinical presentation, morphological features, patterns of the commonly used immunohistochemical stains and follow-up. In our cohort, LGASC was commonly located at the outer aspect of the breast and associated with intraductal papilloma. The morphology of LGASC is characterised by infiltrating small glands and nests with variable squamous differentiation. We also found cuffing desmoplastic (fibrolamellar) stromal change in 75% of patients and peripheral lymphocytic aggregates in 87.5% of patients. P63 and smooth muscle myosin (SMM) were the most common myoepithelial markers used to assist in diagnosis. P63 often stained peripheral tumour cells surrounding invasive glands (circumferential staining in 80% of the cases), mimicking myoepithelial cells. It also stained the small nests with squamous differentiation. However, SMM was negative in 63% of the cases. The vast majority of our cases were triple-negative; only a few had focal and weak expressions of ER and PR. One patient who did not have excision developed lymph node metastasis. Most patients underwent excision or mastectomy with negative margins as surgical treatment; there were no recurrences or metastases in these patients with clinical follow-ups up to 108 months. CONCLUSIONS: LGASC has some unique, although not entirely specific, morphological features and immunohistochemical staining patterns. Fibrolamellar stromal change, peripheral lymphocytic aggregates and variable staining of p63 and SMM are valuable features to facilitate the diagnosis.

Cyto-histologic correlation of crystal-storing histiocytosis: Rare presentation in breast, predating diagnosis of B-cell lymphoma by two years.

Crystal-storing histiocytosis (CSH) is a rare disorder characterized by the accumulation of crystalized immunoglobulins within the cytoplasm of histiocytes. It is often associated with an underlying lymphoproliferative or plasma cell disorder. Most patients with CSH are asymptomatic in regard to the disease and are incidentally discovered. Herein we present cyto-histologic correlation of a rare example of CSH presenting with a two-year interval between original diagnosis of CSH and confirmation of a low-grade B-cell lymphoma.

Biphasic squamoid alveolar renal cell carcinoma: Cytologic features of a rare entity.

Biphasic squamoid alveolar renal cell carcinoma is a newly described rare morphologic variant of papillary renal cell carcinoma. Its characteristic histomorphology and immunophenotype have been well described in the literature. Namely, BSARCC is composed of a dual-cell population with nests of larger squamoid cells surrounded by a single layer of cuboidal cells in alveolar arrangements. Invariably, the squamoid component expresses cyclin D1. More recently, MET alterations have been identified within a subset of BSARCC, raising the possibility for targeted MET inhibitor therapy. To the best of our knowledge the cytomorphologic features of BSARCC have yet to be described. Herein we correlate the cytologic features (percutaneous image-guided fine needle aspiration) of BSARCC to its corresponding histomorphology and immunophenotype (core needle biopsy).

Mammary analogue secretory carcinoma: A challenging case arising in a young man with radiation exposure.

Mammary Analogue Secretory Carcinoma (MASC) is a recently described salivary gland tumor frequently sampled via fine-needle aspiration. The cytologic features of MASC are not entirely distinctive and can simulate acinic cell carcinoma, but the tumor harbors an ETV6 gene rearrangement resulting in an ETV6-NTRK3 fusion gene. We present a case of MASC arising in a 31 year old man with a history of multiple radio-embolization procedures.

Malignant rhabdoid tumor: Cyto-histologic correlation and immunohistochemical characterization of a rare pediatric malignancy and its differential diagnoses.

Malignant rhabdoid tumor of the kidney (MRTK) is a rare aggressive pediatric renal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology and core biopsy. The diagnosis of MRTK is challenging, and requires morphologic, immunohistochemical and clinical correlation to distinguish it from other entities. The differential diagnosis includes Wilms tumor, desmoplastic small round cell tumor, rhabdomyosarcoma, synovial sarcoma, renal medullary carcinoma, and epithelioid sarcoma. Here we describe a case of MRTK diagnosed on renal cytology and core biopsy with immunohistochemistry and follow by nephrectomy with gross and morphologic findings.

Eccrine angiomatous hamartoma: First case in the cytology literature.

A 34-year-old male presented with a swelling on the volar surface of the third digit of his right hand. This swelling was associated with pain and erythema. Ultrasound-guided needle biopsy was performed. Cytologic and histologic preparations together confirmed the diagnosis of a rarely encountered mixed epithelial and mesenchymal proliferation, an eccrine angiomatous hamartoma. To our knowledge, this case is the first to illustrate the cytomorphologic features of this rare lesion.

Malignant gastrointestinal neuroectodermal tumor: Cytologic, histologic, immunohistochemical, and molecular pitfalls.

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare malignant primary gastrointestinal mesenchymal tumor which can be diagnosed via fine-needle aspiration (FNA) cytology. In the context of FNA, the diagnosis requires a cell block and the use of significant resources including immunohistochemical stains and molecular testing. The differential diagnosis of GNET includes clear cell sarcoma (CCS), gastrointestinal stromal tumor (GIST), gastric schwannoma, metastatic melanoma, malignant perivascular epithelioid cell tumor (PEComa) and granular cell tumor, among others. Here we describe a case which was initially diagnosed as malignant granular cell tumor by FNA which was later revised to GNET following the finding of an EWSR1-ATF1 fusion gene rearrangement.

Early squamous cell carcinoma of the oral tongue with histologically benign lymph nodes: A model predicting local control and vetting of the eighth edition of the American Joint Committee on Cancer pathologic T stage.

BACKGROUND: The eighth edition of the American Joint Committee on Cancer staging manual (AJCC8) added depth of invasion to the definition of pathologic T stage (pT). In the current study, the authors assess pT stage migration and the prognostic performance of the updated pT stage and compare it with other clinicopathologic variables in patients with early squamous cell carcinoma of the oral tongue (OTSCC; tumors measuring ≤4 cm) with histologically benign lymph nodes (pN0). METHODS: A multi-institutional cohort of patients with early OTSCC was restaged as per AJCC8. Primary endpoints were local recurrence (LR) and locoregional recurrence (LRR). Influential variables were identified and an LR/LRR prediction model was developed. RESULTS: There were a total of 494 patients, with 49 LR and 73 LRR. AJCC8 pT criteria resulted in upstaging of 37.9% of patients (187 of 494 patients), including 34.5% (64 of 185 patients) from pT2 to pT3, without improving the prognostication for LR or LRR. Both LR and LRR were found to be similar for patients with AJCC8 pT2 and pT3 disease. On multivariate analysis, LR was only found to be associated with distance to the closest margin (hazard ratio, 0.36; 95% CI, 0.20-0.64 [P = .0007]) and perineural invasion (hazard ratio, 1.92; 95% CI, 1.10-0.64 [P = .046]). Based on these 2 predictors, a final proportional hazards regression model (which may be used similar to a nomogram) was developed. The proposed model appeared to be superior to AJCC pT stage for estimating the probability of LR and LRR for individual patients with early OTSCC. CONCLUSIONS: AJCC8 pT criteria resulted in pT upstaging of patients with pN0 disease without improved LR or LRR prognostication. The proposed model based on distance to the closest margin and perineural invasion, status outperformed pT as a predictor of LR and LRR in patients with early OTSCC.

Cystic neutrophilic granulomatous mastitis: The Cleveland Clinic experience with diagnosis and management.

Granulomatous mastitis is an uncommon inflammatory disease that typically presents with painful breast lesions. Recent publications have brought to light a specific subset of granulomatous mastitis patients with a distinct histological pattern of disease termed, "cystic neutrophilic granulomatous mastitis" (CNGM). Although many cases of granulomatous lobular mastitis have been thought to be idiopathic, this rare subset of an uncommon disease has been linked to infections with Corynebacterium species. Herein, a cohort of CNGM patients from a large, tertiary care, North-American, academic medical center is presented. Correlative demographic, clinical, radiographic, pathologic, microbiologic, management, and outcomes data are provided. Collaborative communication between specialists to accurately diagnose and manage these patients is essential to decreasing potential morbidity.

Hyalinized Neurofibromas: Not Just Rare Variants in Skin of the Female Breast.

Although classical neurofibromas are commonly encountered skin lesions, histologic variants are infrequent. We report a greater than 15-year retrospective review of a single institution's experience with the histopathologic diagnosis of neurofibroma of the female breast with a focus on the hyalinized variant. An electronic histopathology record review (CoPathPlus; Cerner Corp, North Kansas City, MO) was conducted from January 1, 2000, to October 16, 2015, for all "neurofibroma" diagnoses rendered in "females" at the anatomical site "breast". All cases were microscopically revisited and subclassified into 1 of 10 histopathologic categories. Immunohistochemistry (IHC) for S100, tryptase, and CD117 were performed on 19 hyalinized and 19 age-matched classical neurofibromas. During the study period, 62,021 breast specimens were reviewed at our institution. Of these, 86 (0.14%) were diagnosed as neurofibromas. Subclassification was as follows: 50 classical (58%), 19 hyalinized (22%), 6 diffuse (7%), 5 cellular (6%), 3 myxoid (4%), 2 epithelioid (2%), and 1 plexiform (1%). All hyalinized and age-matched classical neurofibromas were S100 positive. The mean number of IHC-positive mast cells per high-power field (hpf) was 34.5 by tryptase and 26.8 by CD117 for the hyalinized subset and 22.5 by tryptase and 19.3 by CD117 for the classical cohort. Published literature reports a 2.6% incidence of hyalinized neurofibromas at nonspecial cutaneous sites. Our series details a 22% incidence in the breast. Regarding pathophysiology, there is a statistically significant increase in the average number of IHC-positive mast cells per hpf in hyalinized variants when compared with classical neurofibromas of the breast both by tryptase (P = 0.00157) and CD117 (P = 0.00901).

Concordance of breast fine needle aspiration cytology interpretation with subsequent surgical pathology: An 18-year review from a single sub-Saharan African institution.

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.

Breast cancer risk associated with atypical hyperplasia and lobular carcinoma in situ initially diagnosed on core-needle biopsy.

BACKGROUND: Breast cancer risk estimates for atypical lesions are based primarily on case-control studies of patients with open biopsies. The authors report the cumulative breast cancer incidence after a core biopsy diagnosis of atypical hyperplasia (ductal or lobular) or lobular carcinoma in situ. METHODS: A cohort study with central pathology review was conducted on 393 patients who had core biopsy diagnoses of atypical hyperplasia and lobular carcinoma in situ from 1995 through 2010. Follow-up was available for 255 of 264 patients (97%) at a median of 87 months (range, 3-236 months). RESULTS: There were 212 patients (54%) who were not upgraded on excision and had no personal history of breast cancer. Of these, 21 of 212 (9.9%) developed breast cancer, including 15 invasive carcinomas, 4 ductal carcinomas in situ, 1 pleomorphic lobular carcinoma in situ, and 1 unknown type. The prior core biopsy diagnoses were atypical ductal hyperplasia for 11 patients (52%) and atypical lobular hyperplasia/lobular carcinoma in situ in the remaining 10 patients (48%). The number of atypical foci in the core biopsy was not significantly associated with the subsequent development of breast cancer (P = .42). Of the 15 invasive carcinomas, 11 (73%) were ipsilateral, 11 (73%) were pathologic T1 tumors, 5 (33%) were pathologic N1 tumors, 13 (87%) were estrogen receptor-positive, and 1 (7%) was amplified for human epidermal growth factor receptor 2. CONCLUSIONS: In patients who had an initial diagnosis of atypical hyperplasia or lobular carcinoma in situ on core biopsy, the 7-year cumulative breast cancer incidence was 9.9%. Most tumors were ipsilateral, stage I, estrogen receptor-positive, invasive carcinomas. The current data support close clinical and radiologic follow-up for more than 5 years in this patient population. Cancer 2018;124:459-65. © 2017 American Cancer Society.

The spectrum of malignant diagnoses in cerebrospinal fluid cytology from an adult population: a multi-institutional retrospective review.

INTRODUCTION: Limited updated literature exists about the prevalence and spectrum of malignancies involving cerebrospinal fluid (CSF). In this multi-institutional study, we review our experience with focus on first time malignancy diagnosis in CSF samples of adults. MATERIALS AND METHODS: Institutional databases at 4 academic centers were queried retrospectively for CSFs over a 10-year period. The following data elements were collected: total # of CSFs, total # of CSFs with a malignant diagnosis; for each patient with a first time CSF diagnosis of malignancy: age, gender, diagnosis, prior history of malignancy, and ancillary studies. RESULTS: Twenty-four thousand one hundred forty-two CSFs were collected with a positive for malignancy rate of 2.3% (n = 551). Out of 347 (1.4%) adults with a first-time diagnosis of CSF malignancy 182 (52%) were female (age range: 19-89/mean: 57) and 165 (48%) were male (age range: 20-95/mean: 60). Hematolymphoid malignancies (48%, n = 168) were overall the most common neoplasm. In women, metastatic carcinomas (63%, n = 114) were the leading malignancy, of which the majority were breast primaries. In men, lymphomas/leukemias (64%, n = 106) were the leading malignancy, of which the majority were B-cell lymphomas. Ancillary studies aided the final diagnosis in 110 (32%) cases. For 286 (82%) cases, a prior history of malignancy was available to correlate CSF findings. CONCLUSIONS: A malignancy diagnosis in the CSF of adults is rare. The most common malignancies in females and males are metastatic breast carcinoma and hematolymphoid malignancies, respectively. Metastatic neoplasms account for the majority, with primary central nervous system neoplasms being quite uncommon. History of malignancy and ancillary tests can be helpful.

Editorial: Optimizing Schools of Cytology: Discussions from the 2022 ASC/IAC Cytology Education Symposium, North American Strategies, and European Symbiosis.

This report highlights information and outcomes from the November 2022 ASC/IAC joint Cytology Education Symposium, an annual conference organized by the Cytology Programs Review Committee. The manuscript provides information on shared educational opportunities and practices for cytology students and other learners in anatomic pathology, discusses recruitment strategies for schools of cytology, conveys teaching resources, introduces perspectives on virtual microscopy and online learning, and transmits information about wellness of students in schools of cytology.

Liver Mass as First-Time Diagnosis of Sarcomatoid Anaplastic Thyroid Carcinoma: A Rare Malignancy Presenting at an Unexpected Body Site.

BACKGROUND Anaplastic thyroid carcinomas are aggressive malignancies associated with poor clinical outcomes and challenges in diagnosis. While local/regional disease in the neck is the most usual site of biopsy, in some cases, distant metastases may be the site of initial investigation. CASE REPORT A 66-year-old woman with a clinical concern for diffuse metastatic malignancy of unknown primary presented to the Emergency Department (ED) with jaundice and shortness of breath. Recent laboratory test results revealed an elevated CA 19-9. Urinalysis revealed hematuria, proteinuria, and hyperbilirubinemia. She had a computed tomography (CT) scan of the chest, abdomen, and pelvis revealing diffuse involvement of the liver, lungs, adrenals, kidneys, thyroid, pancreas, gallbladder, and brain, but had not yet had a biopsy for definitive diagnosis. An ultrasound-guided liver biopsy was evaluated for cytological features, histological features, and pattern of immunostaining. The cytomorphological histological features were concerning for a high-grade malignancy. Immunohistochemical evaluation revealed that the lesion was positive for CK-AE1/AE3, BRAF, CK7, GATA3, SATB2, PAX8, and TTF-1, but the lesion was not reactive to the following stains: napsin, CK20, CDX2, PCEA, calcitonin, ER and thyroglobulin. The patient was diagnosed with a sarcomatoid anaplastic thyroid carcinoma and died within a few days after diagnosis. CONCLUSIONS This case illustrates that unanticipated specific diagnoses of widely metastatic anaplastic thyroid carcinoma are feasible when integration of patient history, clinical setting, imaging findings, clinical laboratory results, cytomorphology, histomorphology, and results of ancillary immunohistochemical testing are thoughtfully pursued and synthesized.

Ductal Carcinoma Arising in a Squamous Epithelial Inclusion Cyst within an Axillary Lymph Node: A Challenging Nodal Metastasis.

Introduction. Assessment of axillary lymph nodes in breast carcinoma is an important part of staging to guide appropriate clinical management. Lymph node inclusions of different types, including nevoid, squamous, and glandular, are rare but have been reported in multiple different anatomic locations including the axilla. These can result in diagnostic challenges and pose risks of misdiagnoses. Rarely, malignancies may arise intrinsic to otherwise incidental benign nodal inclusions. Case Presentation. We report a case of ductal carcinoma diagnosed within a squamous epithelial inclusion cyst within an axillary lymph node in a patient with pure ductal carcinoma in situ (DCIS) of the ipsilateral right breast. To our knowledge, this is the fifth report in the literature of breast carcinoma confirmed within an axillary inclusion in a patient with pure DCIS. Evaluation of the primary DCIS and lymph node inclusions, by routine and immunohistochemical stains, was performed for assessment. Discussion. The presence of lymph node inclusions can pose a challenge in assessment of benignity and malignancy, on frozen and permanent histologic sections. Pathologists should carefully evaluate lymph node inclusions to ensure that intrinsic malignancies are not missed within rare otherwise benign appearing incidental epithelial rests.

Lymphangioleiomyomatosis in lymph node cytology: Another "Floating Island" to visit.

Lymphangioleiomyomatosis (LAM) is a rare disease with variable presentations. The neoplastic cells in LAM demonstrate a unique and diagnostically important "myomelanocytic" phenotype. Cytologic reports of LAM are infrequent and have not in the past emphasized the floating island pattern in which circumscribed aggregates of lesional cells are rimmed by appliques of flattened endothelium. This case illustrates the cytology of LAM and emphasizes that the floating island cytoarchitectural pattern more classically associated with entities such as hepatocellular carcinomas may be seen in cytological preparations of LAM at unanticipated body sites.

TRPS1 outperforms GATA3 in pleural effusions with metastatic breast carcinoma versus mesothelioma.

INTRODUCTION: In evaluating malignant pleural fluid cytology, metastatic adenocarcinomas and mesotheliomas are often differential diagnoses. GATA binding protein 3 (GATA3) has historically been used to confirm metastatic breast carcinomas; however, GATA3 has low specificity if mesothelioma is included in differential diagnoses. Trichorhinophalangeal syndrome type 1 (TRPS1) protein is expressed in all types of breast carcinomas, with reported high specificity and sensitivity. We investigated the performance of TRPS1 immunohistochemistry (IHC) and compared it to GATA3 in pleural fluids diagnosed with metastatic breast carcinoma and mesothelioma. METHODS: Thirty-six consecutive ThinPrep pleural fluids and 4 pleural fine needle aspirations (FNAs) with diagnoses of metastatic breast carcinoma (21) and mesothelioma (19) were retrieved, and IHC with TRPS1 and GATA3 was performed on all. Immunoreactivity scores for TRPS1 were calculated by multiplying percentage of immunoreactive cells by staining intensity. Immunoreactivity scores were negative if 0 or 1, low positive if 2, intermediate positive if 3 or 4, or high positive if 6 or 9. Nuclear immunoreactivity of ≥10% with at least moderate intensity was judged GATA3 positive. RESULTS: GATA3 showed immunoreactivity in all metastatic breast carcinomas and 84% of mesotheliomas. TRPS1 was immunoreactive in all breast carcinoma cases (18 with a score of 9 and 3 with a score of 6). TRPS1 showed low positivity in 5% of mesothelioma cases with all other cases being negative. CONCLUSION: When cytomorphologic differential diagnoses of mesothelioma exist, TRPS1 is a more specific marker than GATA3 for confirmation of metastatic breast carcinoma in pleural fluid cytology.

Evaluation of automated sample preparation system for lymph node sampling.

Background: Endobronchial ultrasound-guided transbronchial fine needle aspiration (EBUS-FNA) has revolutionized the diagnostic and staging approach to non-small cell carcinoma and thoracic lymphadenopathy. However, obstacles to efficacy of rapid on-site evaluation (ROSE) of the samples include variability in sample quality and slow and cumbersome process in the procedure room leading to extended procedure time. The purpose of this pilot study was to evaluate the feasibility and specimen quality of lymph node biopsies prepared through a novel automated system for automated fixation, drying and staining compared to standard slide preparation method. Methods: We performed a prospective, single-center pilot feasibility study of patients undergoing EBUS. Samples were split into conventional standard of care (SOC) slide preparation and preparation using the device ("instrument"). Pathologists compared the SOC slides to the slides prepared by the automated system and assessed the following metrics: nuclear and cytoplasmic quality, presence of debris/artifact, staining quality, creation of a monolayer, and ease of adequacy/diagnosis assessment. A score between 1 (lowest quality) and 3 (highest quality) was assigned to the above metrics. Results: Sixty patients were recruited. One to three lymph nodes were sampled for each patient for a total of 72 samples collected. The mean scores of each assessment category showed no statistical difference between the two preparation techniques except for improved monolayer creation in the instrument samples. Thirty of thirty-one (96.8%) paired samples in the final analysis showed diagnostic equivalency between the automated slides and conventional slides; the discordant pairing was reported to be suspicious on the instrument sample and atypical on the SOC. Conclusions: Study results suggest that slides prepared by the automated system are of adequate quality for adequacy assessment with diagnostic concordance when compared to SOC slides.