Faculty Bibliography

Follicular dendritic cell sarcomas (FDCS) are rare tumours of lymph nodes and extranodal tissues which are grouped with the histiocytic and dendritic cell neoplasms. The diagnosis is usually made after thorough clinical and pathological examination with immunohistochemical analysis. Difficulties persist in diagnosing FDCS on cytological preparations. We report herein a case of a 57-year-old female who presented with a right neck mass of 5 months duration. Computed Tomography (CT) imaging of the neck reported a necrotic right level IIb lymph node and asymmetric fullness of the right palatine tonsil. Fine needle aspiration (FNA) biopsy revealed numerous spindle, oval and stellate neoplastic cells, arranged singly and in syncytia with moderate nuclear pleomorphism, vesicular chromatin pattern, and prominent nucleoli, sprinkled with small lymphocytes. The tumour cells were strongly diffusely positive for CD21, CD23, and D2-40 immunostaining on cell bock sections, but were negative for CD1a and CD34, supporting the diagnosis of FDCS. Follow-up surgical pathology on the resection showed histopathological features and an immunohistochemical profile consistent with FDCS.

Prostate cancer is the most frequently diagnosed cancer in males and its development and progression remains an important area of study. Recently, long non-coding RNAs (lncRNAs) have been evidenced as key players in cancer pathogenesis. Specifically, dysregulation of long non-coding RNA (lncRNA) expression has shown to affect tumor proliferation and metastasis, acting as either tumor suppressors or oncogenes. However, its specific mechanisms and functions in prostate cancer remain unclear. This review provides an overview of currently available information on prostate cancer-related lncRNAs, including GAS5, GAS-007, MEG3, PCA3, PCAT14, PCAT1, PVT1, UCA1, SChLAP1, MALAT1, HOTAIR, and NEAT1. Notable tumor growth inhibitors include GAS5 and MEG3. GAS5 is evidenced to interfere with the AKT/MTOR signaling pathway through targeting microRNA mir-103. MEG3, however, is proposed to inhibit the cycle, sponge miR-9-5p, and induce gene silencing. PCAT1, PVT1, and UCA1 are important tumor growth promoters. PCAT1 is indicated to be a transcriptional repressor, a mir-145-5P sponge, and a P13K/AKT pathway activator. Studies suggest that PVT1 acts via microRNA targeting and regulating proliferating cell nuclear antigen. UCA1 may sponge miR-204 and miR-331-3p as well as regulate myosin VI. Thorough understanding of these lncRNAs may elucidate new aspects of prostate cancer pathology and serve a pivotal role in developing novel diagnostic and prognostic techniques.

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors that co-express smooth muscle and melanocytic markers. They have a predilection for gynecologic organs where they present a unique diagnostic challenge due to morphologic and immunohistochemical overlap with more common smooth muscle and stromal tumors. Limited information regarding natural history owing to rarity of this tumor makes accurate risk stratification difficult. Five different prognostic classification systems (2 for PEComa of all sites and 3 specific for gynecologic PEComa) have been proposed. We have described clinicopathologic features of 13 new cases of gynecologic PEComa, and tested all 5 prognostic algorithms in a total of 67 cases of gynecologic PEComa (54 cases from previously published studies). Receiver Operating Characteristic curves were built and area under curve (AUC) was calculated to evaluate predictive accuracy. The 'modified gynecologic-specific criteria' showed high sensitivity and specificity and yielded the highest AUC (0.864). The earlier version of it, 'gynecology-specific criteria' suffered from lower specificity (AUC = 0.843). Post hoc McNemar test confirmed significant difference between the performances of 'modified gynecology-specific criteria' and 'gynecology-specific criteria' (p = .008). The 'original' Folpe criteria for PEComas of all sites showed low specificity, had lower AUC (0.591) and was inapplicable in 18% of cases. Its two later versions ('revised' Folpe criteria and 'modified' Folpe criteria) also yielded lower AUC (0.690 and 0.591respectively). We have shown that 'modified gynecologic-specific' algorithm predicts clinical outcome of gynecologic PEComa with high accuracy and have validated its use for prognostic stratification of gynecologic PEComa.

Introduction: SARS-CoV-2 (COVID-19) is known to cause severe respiratory infections with occasional accompanying pleural (PE), pericardial (PCE) or peritoneal effusion (PTE). The effect of COVID-19 disease on effusion cytology is not yet known. Therefore, our study aims to examine the cytomorphologic features and work-up of effusion fluid in patients in recovery from COVID-19 infection versus those with active disease.
Material(s) and Method(s): PE (n=15), PCE (n=1), PTE (n=19) samples from hospitalized patients with COVID-19 infection (6/1/2020-12/30/2020) were reviewed. EFs with metastatic carcinoma were excluded. Differential cell count (DCC), cytomorphology, and immunostains of EFs were retrospectively evaluated by a board-certified cytopathologist and compared between patients with active infection (AI, n=22, positive COVID-19 nucleic acid amplification test (NAAT) within 2 months) and recovery phase from COVID-19 (RC, n=13, negative COVID-19 NAAT for >2 months).
Result(s): Cytology diagnoses were: negative for malignancy (n=30), atypical (n=4), suspicious for malignancy (n=1). AI cases showed more atypical mesothelial cells than RC cases (Table 1, p<0.05), some with enlarged nuclei with prominent nucleoli and occasional multi-nucleation (Figure 1), and some with bizarre nuclei (Table 1, p<0.01). Immunostains were performed more often in AI than RC cases (50.0% vs 7.7%, p<0.05). DCC (available in 28 cases) showed no significant difference amongst AI and RC cases (Figure 1, p>0.05).
Conclusion(s): Our study found atypical and bizarre mesothelial cells to be present more often in effusions of cases with active COVID-19 infection than in samples from patients in recovery, though DCCs did not show significant difference. Diagnosis of malignancy may be considered in cases with such nuclear atypia, which explains increased immunostain work-up in AI cases. It is important for cytopathologists to consider the patients' COVID-19 infection status when evaluating effusion cytology cases. [Formula presented] [Formula presented] [Formula presented]
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Introduction: Preoperative diagnosis of pancreas ductal adenocarcinoma (PDAC) on endoscopic ultrasound guided fine needle aspiration (FNA) cytology is often required to determine proper therapy. Accurate cytopathology diagnosis on FNA may be challenging due to limited/suboptimal cellularity and gastrointestinal contamination with accurate diagnoses necessitating consideration of the full clinical and radiologic picture in evaluating the pancreatic lesions. In this study, we investigated predictive value of integrating cytology diagnosis, radiologic and clinical features in diagnosing pancreatic adenocarcinoma.
Material(s) and Method(s): Pancreatic FNA cases from 1/2016-12/2018 with >18 months of follow-up or histopathology diagnosis on surgical resection were retrieved (n=203). Cases were categorized as "Adenocarcinoma" or "Benign" according to the surgical resection pathology or clinical follow-up. Their documented serum CA19-9 level, and in-house radiologic reports were studied (n=177, Table 1). A multiplayer perceptron neural network (MNN) was trained and tested for the ability of using the integrated clinical and radiologic features and cytologic diagnosis to distinguish between benign and malignant cases.
Result(s): The sensitivity, specificity, and accuracy for pancreatic FNA cytology alone was 77.5%, 97.6%, and 88.4%, respectively. There were significant correlations between malignant outcome and cytology diagnosis, CA19-9 level and involvement of common bile duct (CBD), pancreatic duct (PD), superior mesenteric artery (SMA) or superior mesenteric vein (SMV) (Table 1, p<0.001). Integration of the cytology diagnosis and CA19-9 level showed 92% accuracy in predicting surgical outcome. The MNN highlighted cytopathology to be the most important factor in predicting pancreatic lesion outcomes, followed by the serum CA19-9 level and involvement of the SMA (Figure 1).
Conclusion(s): Integration of the clinical and radiologic information with cytology diagnosis can improve accuracy in evaluating pancreatic adenocarcinomas, especially in suboptimal FNA cytology specimens. [Formula presented] [Formula presented]
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Introduction: TERT promoter mutations in thyroid carcinoma suggest worse prognosis based on findings of a small number of studies. Additionally, pathologic features and clinical behavior of indeterminate thyroid nodules (ITN) with TERT promoter mutations remain less studied. Our study aims to explore the clinicopathologic features of ITN with TERT promoter mutations.
Material(s) and Method(s): A search conducted in our electronic medical record between 2015-2018 identified 18 cases with indeterminate thyroid fine-needle aspiration (FNA) cytology (Bethesda Class III, IV, and V) and a TERT mutation on molecular testing. 17 patients underwent thyroidectomy and were the subjects of this study.
Result(s): The mean age was 65 (range 38-83) with a female to male ratio of 9:8. The FNA Bethesda diagnoses were Class III in 9, IV in 8, and V in 1. Majority of patients who underwent thyroidectomy had malignant nodules (14,78%). Thyroidectomy diagnoses included classic PTC (5,29%), FVPTC (5,29%), follicular variant of papillary carcinoma (3,17%), poorly differentiated thyroid carcinoma (1, 6%), follicular adenoma (2,11%) and NIFTP (1,6%). Additional alterations were present in 11 cases, including NRAS(6), KRAS(2), and BRAF V600E (3). Of three cases with concurrent BRAF V600E mutation, two were metastatic, and one had tall cell features. Of two follicular adenoma cases, one had a concomitant NRAS mutation, and the other displayed negative results on Afirma testing. Malignant cases tended to occur in older patients, the majority exhibited follicular architecture, frequent oncocytic morphology, and higher pathologic stage (pT3 in 92%, pT2 in 8%).
Conclusion(s): Most TERT promoter mutations in ITN cytology are associated with high risk of malignancy and these malignancies are associated with unfavorable features such as advanced stage, capsular/vascular invasion, and metastatic disease. Few TERT promoter mutations have a benign outcome. Further studies on ITNs with TERT mutations are needed to determine the optimal management of these nodules.
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Introduction: The Paris System classifies polyoma virus cytopathic effect (P-CPE) as "negative for high grade urothelial carcinoma (HGUC)". However, P-CPE may raise false suspicion for HGUC. Conversely, HGUC cells may display considerable degenerative nuclear changes mimicking P-CPE. Thus, P-CPE remains a known source of "atypia" in urine cytology. The aim of our study was to determine the frequency of P-CPE cases reported as atypical urothelial cells (AUC) in our laboratory, and to assess the diagnostic utility of SV40 immunostaining (IHC) in this setting.
Material(s) and Method(s): Urine cytology cases, all processed as single Thin prep (TP) slides, were searched for P-CPE diagnosis from 2018 to 2020. An additional slide was prepared for a subset of 40 randomly selected cases (19 P-CPEs, 21 negative controls) for SV40 IHC validation on TP slides.
Result(s): There were 111 urines with P-CPE. 51% were included in this study (Figure 1). Of these, 25% were diagnosed as negative for HGUC, 72% as AUC, and 3% as suspicious for HGUC. Follow-up histology showed HGUC in 3 (5%) cases (2 with AUC and 1 with suspicious for HGUC presurgical cytology). SV40 IHC was positive in 61.5% of cases in the P-CPE group and negative in 38.5% including one with confirmed HGUC on biopsy (Figure 2). In the control group, SV40 IHC was negative in 88% and equivocal in 12% (Figure 3). The difference in SV40 IHC between the P-CPE and control group was statistically significant (p<0.001).
Conclusion(s): Majority of urine samples with P-CPE were reported as AUC with a very low incidence of confirmed HGUC. SV40 IHC aided in the confirmation of viral infection. Our study shows that once the source of atypia is confirmed as polyoma virus with SV40 IHC, downgrading atypia to negative can safely be accomplished without the concern for missing a high-grade lesion. [Formula presented] [Formula presented] [Formula presented]
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Introduction: Pancreatic neuroendocrine tumors (PNET) are relatively uncommon neoplasms. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been shown to be an efficient method for preoperative assessment of pancreatic tumors; however, the role of cytologic grading of PNETs is unclear. We aim to evaluate cytologic diagnosis and grading of PNETs by correlating with histopathology.
Material(s) and Method(s): Cytopathology cases with a diagnosis of PNET from 6/2011-6/2020 were tabulated and compared with their corresponding surgical pathology to evaluate the diagnostic accuracy of EUS-FNA. In addition, tumor grading based on Ki-67 immunohistochemistry was correlated between cytologic and histologic specimens (Cohen's kappa coefficient).
Result(s): Thirty-nine cases of EUS-FNAs with PNET diagnosis and concomitant histologic evaluation were included. EUS-FNA showed a positive predictive value of 85% for PNET diagnosis. There were 6 discrepant cases (15%), including: 1 mixed ductal-neuroendocrine carcinoma, 1 PNET with concomitant high-grade carcinoma, 1 metastatic renal cell carcinoma, 1 solid pseudopapillary neoplasm, and 2 cases of chronic pancreatitis, potentially explained by under-sampling, scant cellularity and/or absence of adequate cell block for immunostaining (Table 1).Nineteen cases had Ki-67 immunostaining on both cytologic and histologic specimens with a concordance of 58% (Table 2). All discrepancies in Ki-67 evaluation were due to underscoring in cytologic samples. Cyto-histologic grading correlation was fair (Cohen's Kappa coefficient=0.24).
Conclusion(s): EUS-FNA is a valuable minimally invasive diagnostic tool in the preoperative diagnosis of PNETs with a positive predictive value of 85% in this cohort. Cyto-histologic grading correlation was fair, which suggests that applying surgical pathology ki-67 grading cut-off points to cytology sample evaluations may not be appropriate. All cyto-histologic grading discrepancies in our study were due to underscoring in cytologic samples, which might be related to sampling issues or tumor heterogeneity.
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Introduction: Our study aimed to assess the sensitivity (SN) and specificity (SP) of fluorescence-in-situ-hybridization (FISH) alone and as an adjunct to routine cytology for the detection of malignancy in biliary tract lesions.
Material(s) and Method(s): Bile duct brush specimens with FISH results from 1/2013-1/2020 were tabulated yielding 55 cases. Cases were classified as "Benign" where surgical resection showed benign findings or follow-up was uneventful >18 months and as "Malignant" where surgical pathology or clinical follow up identified malignancy in the pancreatobillary system (40 cases). Cases not falling under these categories were excluded. Cytologically suspicious and positive cases were designated as "positive." FISH positive and "equivocal" results were also designated as "positive." When examining the combined cytology-FISH results, cases were designated as "positive" if either cytology or FISH test was "positive." Atypical cytology cases were excluded.
Result(s): 21/40 cases fell under benign or malignant categories. 5/21 cases had malignant surgical follow-up: 4 pancreaticobiliary ductal adenocarcinoma and 1 Hodgkin lymphoma. FISH showed high SP (100%) and low SN (33.3%) in diagnosing malignancy in bile brush cytology. In cytology alone, FISH alone and the combined cytology-FISH testing, there was a statistically significant difference in risk-of-malignancy between Positive and Negative diagnostic categories, p<0.05(Table 1). Accuracy improved using combined cytology-FISH results over either test alone, area under the curve (AUC: Cytology=0.8; FISH=0.717; Combined test=0.85) (Figure1).
Conclusion(s): Cytology, FISH and combined cytology-FISH results all showed higher risk-of-malignancy values in positive compared to negative categories. The FISH-cytology combination may improve the SN of detecting malignancy in biliary tract lesions. Sample size may have been too small to detect a significant difference between combined cytology-FISH results versus either test alone. However, due to the potential clinical impact of improving bile duct brush cytology accuracy, our results should be evaluated further in larger samples. [Formula presented] [Formula presented]
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