Comparison of Claudin-4, BerEP4, Carcinoembryonic Antigen and MOC31 in Serous Fluids Metastases Demonstrate High Sensitivity of Claudin-4 at Low Cellularity.

INTRODUCTION: Claudin-4 has been described as a highly sensitive immunocytochemical marker for detection of metastatic carcinoma cells in effusion cytology specimens. This study aims to challenge the performance of claudin-4 in different types of malignancies and low cellularity specimens, by comparison with other markers in a large cohort of carcinomatous effusion specimens. METHODOLOGY: Cell block preparations from peritoneal and pleural fluid specimens were retrieved, with malignant (carcinoma) diagnoses confirmed by review of hospital diagnosis code and pathology reports. Claudin-4, BerEP4, CEA, and MOC31 immunocytochemistry were performed and scored by expression proportion and intensity. Tumor cellularity was assessed for subgroup analysis of low cellularity specimens. RESULTS: Totally 147 specimens (70 pleural, 77 peritoneal) of 68 lung, 62 breast, 9 gynecological, and 7 gastrointestinal carcinomas were retrieved. The average proportion expression of claudin-4 was highest (89.6%, vs. CEA 40.5%, BerEp4 18.6%, MOC31 16.8%) and the percentage of strong expression was highest for claudin-4 (72.1%). Expression levels of claudin-4 were consistently higher than other markers in subgroups of all primary sites. The difference was more significant for low cellularity specimens. High (≥50%) proportion expression was seen for 96.61% of cases for claudin-4 (vs. BerEp4 8.77%, CEA 46.55%, MOC31 8.77%, p < 0.001). These factors contributed to a low concordance between claudin-4 and BerEp4, CEA and MOC31 (K = 0.010-0.043). CONCLUSION: Claudin-4 is more sensitive than CEA, BerEp4 and MOC31, suitable for low cellularity specimens of most types of metastatic carcinoma and is a robust immunocytochemical marker for carcinoma that can be used solitarily.

Cytomorphologic comparison of upper urinary tract urothelial carcinomas and renal cell carcinomas on urine cytology.

INTRODUCTION: Compared to urothelial carcinomas (UCs), the cytomorphology of renal cell carcinomas (RCCs) is underdescribed. This study aims to investigate whether UCs and RCCS of the upper urinary tract can be differentiated cytologically, and to identify distinguishing cytomorphological features. METHODOLOGY: Consecutive urine cytology specimens with atypical/C3, suspicious/C4 or malignant/C5 diagnoses matched with a nephrectomy or ureterectomy specimen with UC or RCC over a 15-year period were reviewed for cellularity, architecture, background composition and cytomorphologic features. RESULTS: Totally 132 specimens were retrieved, comprising 24 RCCs and 108 UCs. Clear cell RCC (CCRCC) (n = 18) was the most common RCC. Urine cytology specimens from UC showed a trend of higher cellularity (p = 0.071) against RCC and was significant in subgroup analysis with CCRCC (p < .001). Epithelial structures in sheets, tubules, and papillae were exclusive in specimens of UC (p < .05). For background features, squamous cells were more common for RCC (p = .006) including CCRCC (p = .003), whereas polymorphs (p = .011) and necrotic material (p = .010) were associated with UC. Average nuclear size was larger and nuclear size variation (p < .001) and nuclear-cytoplasmic ratio (p = .001) were greater in UC (p = .001) than RCC. Comparing RCC to high-grade UCs only, nuclear-cytoplasmic ratio maintained statistical significance (p = .006) while average nuclear size showed a trend (p = .063). CONCLUSION: A clean background free of tumor necrosis and polymorphs, and the lack of complex tumor fragments favors RCC. UCs also display larger nuclear size, higher nuclear size variation and nuclear-cytoplasmic ratio. These cytomorphological features with corroboration of clinical/radiological findings, can aid in raising a diagnosis of RCC.

Comparison and review of abrasive bronchial brushing versus non-abrasive aspiration, lavage and washing - Higher sensitivity but with risk of over-diagnosis for bronchial brushing.

Bronchial exfoliative cytology is classified as non-abrasive (washing, aspiration and bronchoalveolar lavage) and abrasive (brushing). Brush abrasion dislodges epithelial cells but can induce bleeding and cytomorphologic artifacts. In this study, the largest cohort to date of bronchial cytology specimens were referenced against bronchial biopsy as the reference standard. Findings in the study will be useful for selecting biopsy modality and reducing necessary procedural risks. All consecutive bronchial cytology and bronchial biopsy from 1995 to 2022 were retrieved. The diagnoses were reviewed and categorized into five-tiered diagnostic categories to compare diagnostic agreement and concordance. Review of 14,148 specimens yielded 3963 non-abrasive, 2378 abrasive cytology specimens matched to biopsy, with 4355 matches between non-abrasive and abrasive cytology specimens. Agreement between non-abrasive and abrasive cytology was moderate (κ = 0.580), and similar when referenced against biopsy (κ = 0.456 (non-abrasive), κ = 0.498 (abrasive)). Abrasive bronchial cytology showed a higher percentage of malignant diagnosis (20.95 % vs. 12.63 %, p < 0.001) and over-diagnosis rate (36.40 % vs. 29.79 %, p < 0.001), but higher sensitivity (0.747 vs. 0.572, p = 0.002). For subgroup analysis of transbronchial biopsies, matched abrasive cytology showed higher discordant rates (p < 0.05) and lower accuracy (0.907 vs. 0.873, p = 0.020). With the added bleeding risk associated with brushing, abrasive techniques may only be preferable in cases with clinical or bronchoscopic suspicion of malignancy, in particular endobronchial mucosal lesions. For routine bronchoscopy, non-abrasive bronchial cytology appears to be adequate.

Urine cytology in the detection of renal cell carcinomas - a territory-wide multi-institutional retrospective review of more than 2 decades.

INTRODUCTION: Compared with urothelial lesions of the upper urinary tract, the diagnostic performance of urine cytology in detection of renal cell carcinomas is underreported. This study aims to establish the role of urine cytology in the assessment of renal carcinomas by a multi-institute review of urine cytology from nephrectomy confirmed renal cell carcinomas, referenced against renal urothelial and squamous cell carcinomas. METHODS: Records of nephrectomy performed from the 1990s to 2020s at three hospitals were retrieved and matched to urine cytology specimens collected within 1 year prior. Patient demographics, specimen descriptors, and histology and staging parameters were reviewed and compared against cytologic diagnoses. RESULTS: There were 1147 cases of urine cytology matched with renal cell carcinomas, with 666 renal urothelial/squamous carcinomas for comparison. The detection rate for urothelial/squamous (atypia or above [C3+]: 63.1%; suspicious or above [C4+]: 24.0%) were higher than renal cell carcinoma (C3+: 13.1%; C4+: 1.5%) (p < 0.001). The positive rate for upper tract urine exceeded other collection methods at 45.0% (C3+) and 10.0% (C4+) (p < .01). Other factors associated with increased positive rates were male sex, collecting duct carcinoma histology, nuclear grade, and renal/sinus involvement (p < .05). Multivariate analysis revealed additional positive correlations with presence of sarcomatoid tumor cells, lymphovascular invasion, and perinephric fat involvement (p < .05). Larger lesion size and higher urine volume did not improve detection rates (p < .05). CONCLUSIONS: The detection rate of renal cell carcinomas is suboptimal compared with urothelial carcinomas, although urine samples collected from cystoscopy or percutaneous nephrostomy significantly outperformed voided urine specimens.

Predictors of an informative or actionable cytological diagnosis on repeat breast aspiration after an insufficient aspirate: a multicentre retrospective review.

An insufficient/inadequate diagnosis on fine-needle aspiration cytology (FNAC) of the breast is not an uncommon diagnostic dilemma. This study aims to review the rate and clinical features predicting an informative or actionable diagnosis on repeating breast aspiration after an insufficient aspirate. METHODS: Unsatisfactory/insufficient/inadequate or equivalent breast aspirates were retrieved from the involved institutions, and those with a repeat aspiration performed within 365 days were included. Clinical and radiological information were retrieved. Available cytological slides were reviewed. RESULTS: Totally 539 paired aspirates were retrieved, with 61.2% (n=330/539) and 10.9% (n=59/539) cytological diagnosis being informative (not insufficient) and actionable (not insufficient nor benign) on repeat aspiration. Younger age (p=0.005) was associated with an informative diagnosis and prior radiotherapy (p=0.097) and insufficient aspirates performed under free-hand (p=0.097) trended with an actionable diagnosis. Radiological findings of calcification (p=0.026) and hyperechogenicity (p=0.045), a small lesion size on initial (p=0.037) and repeat (p=0.059) radiological assessment and interval size increment (p=0.019) correlated with informative/actionable diagnoses. Cytomorphological parameters, except for a trend with crushing artefact (p=0.063), do not correlate with the cytologic diagnosis of the repeat aspirate. CONCLUSIONS: Repeating breast FNAC on patients after an insufficient diagnosis yields an informative ('sufficient') result in over 60% of cases. Small lesions with calcification, hyperechogenicity and/or interval size increment are more likely to yield diagnostic results on repeat aspiration and indicate select patients suitable for repeat FNAC over more invasive procedures. The lack of associations with cytomorphological parameters cautions against overinterpretation of insufficient breast aspirates.

Prevalence and interpretation of AFF immunostain of DEK::AFF2 fusion-associated papillary squamous cell carcinoma in a retrospective cohort of recurrent sinonasal papillomas.

DEK::AFF2 fusion-associated papillary squamous cell carcinoma is a novel entity characterized by its unique translocation and malignant clinical course. In this study, AFF immunohistochemistry (IHC) was performed in recurrent sinonasal papillomas for reviewing the prevalence of undiagnosed DEK::AFF2 carcinomas and to investigate the performance of AFF IHC in diagnosis of DEK::AFF2 carcinomas. Recurrent sinonasal papillomas after surgical excision in a two-decade period were retrieved. Histologic slides were reviewed for features of DEK::AFF2 carcinoma. AFF IHC was performed, and cases with any (> 1%) nuclear positivity were validated by DEK break apart fluorescence in situ hybridization. Totally 43 cases were included, comprising 28 inverted, 6 exophytic, one oncocytic, and 8 non-specified sinonasal papillomas. Five (11.6%) cases exhibited positivity to AFF IHC. Three cases exhibited patchy weak to moderate staining intensity predominantly in a granular cytoplasmic pattern. Two cases exhibited strong and diffuse (> 90%) nuclear staining. Cases showing weak staining were negative for DEK rearrangement, while those with strong staining were positive. Both cases of DEK::AFF2 carcinoma showed aggressive behavior with extensive local invasion and nodal metastasis. Background stromal plasma cells, when present, consistently showed strong and diffuse staining. AFF IHC was further performed in plasmacytoma samples as control and showed strong and diffuse immunoreactivity. A significant minority of recurrent sinonasal papillomas represent DEK::AFF2 carcinomas. Granular, cytoplasmic, or incomplete AFF staining should be considered as negative. In view of the rarity of DEK::AFF2 carcinomas, plasma cells and plasma cell neoplasms are potential for internal and surrogate external controls.

Cytomorphological Assessment in Aspirates of Ductal Carcinoma in situ: Correlations with Histopathologic Grade, Architectural Pattern, and Invasion.

INTRODUCTION: Fine-needle aspiration biopsy (FNAB) of the breast is an effective and widely adopted diagnostic technique. Histopathologic grading of ductal carcinoma in situ (DCIS) has prognostic significance. In this current study, FNAB of DCIS was reviewed to identify parameters that predict grading, histopathologic architecture, and presence of invasion in DCIS. METHODS: Aspirates from histopathology-proven cases of DCIS were retrieved and reviewed for cytomorphologic parameters including cellularity, composition, epithelial fragment architecture cellular/nuclear features. RESULTS: In total 104 aspirates were reviewed. Cytopathologic cellular features - large nuclear size (p = 0.005), prominent nucleoli (p = 0.011), increased nuclear membrane irregularity (p = 0.043), high variation in nuclear size (p = 0.025), and presence of apoptotic figures in epithelial structures (p < 0.001); and background debris (p = 0.033) correlated with a high-grade diagnosis. Cytoplasmic vacuolation (p = 0.034) was seen exclusively in non-high-grade aspirates. Epithelial fragment architecture did not correlate with grading. A predominance (≥50%) of solid aggregates and papillary fragments on FNAB correlated with histopathologically solid (p = 0.039, p = 0.005) and papillary (p = 0.029, < p = 0.001) patterns. No parameter showed correlation with invasion. CONCLUSION: FNAB is effective in predicting DCIS grading. Epithelial fragment architecture assessment is limited to papillary or solid types, and FNAB cannot predict focal invasion in DCIS.

Keratinization in atypical glandular cell clusters as a cytological clue to endometrioid carcinoma on cervical cytology.

INTRODUCTION: Specific diagnosis of endometrial carcinomas on cervical cytology is difficult with few useful cytomorphological clues reported. This study reviews a cohort of cervical cytology to investigate the presence of keratinization in atypical glandular cells (AGC), an undescribed cytomorphological clue for identifying endometrial endometrioid carcinomas on cervical cytology. METHODS: Cervical cytology slides from patients with a histologic diagnosis of endometrial endometrioid carcinoma were reviewed for the presence of keratinization associated with AGCs. Corresponding histology slides were reviewed for tumour grading and degree of squamous differentiation. RESULTS: In total, 42 cases of cervical cytology specimens from 41 patients were retrieved, including 7 (16.7%) with keratinization associated with AGCs seen and 35 (83.3%) without. Comparison of histologic grading did not demonstrate an association with the presence of keratinization on cytology (p = 0.565). Corresponding histology slides were available for 37 cases. Cytologic and histologic keratinization were associated statistically (p = 0.002). Frank keratinization was seen on histologic slides of five cases, with four also showing cytologic keratinization. Area of squamous differentiation, including squamous morule formation, did not correlate with keratinization on cytologic preparation (p = 0.185). CONCLUSION: Histologic and cytologic keratinization are observed in endometrioid endometrial carcinomas. Such is reflected in cervical cytology by the presence of orangeophilic, rigid and acellular fragments within or associated with AGC clusters. Keratinization, when identified with AGCs, should be regarded as a cytologic clue suggestive of an endometroid carcinoma of endometrial origin.

Aspiration cytology of liver abscess uncovering metastatic rectal mucosal melanoma-A case report.

Aspirates of liver abscess are frequently encountered in routine practice and are often of a low index of suspicion. However, necrotic liver metastasis clinically and radiologically mimics liver abscesses, and malignant cells can be obscured in an inflammation-rich background on cytology. It is important to recognise malignant neoplasms in this scenario, in particular uncommon conditions such as metastatic mucosal melanoma.

The First Report of Cytology of DEK::AFF2 Fusion-Associated Papillary Squamous Cell Carcinoma on Fine-Needle Aspiration.

DEK::AFF2 fusion-associated papillary squamous cell carcinoma is a recently characterized sinonasal malignancy defined by its unique translocation. DEK::AFF2 carcinomas may be deceptively monotonous and lack keratinization, resembling transitional epithelium. The lack of traditional cytological atypia presents diagnostic challenges. Our case describes the first report of fine-needle aspiration cytology of a lymph node involved by DEK::AFF2 carcinoma in a patient with previously resected sinonasal inverted papilloma with carcinomatous transformation six years prior to presentation. This aspirate consisted of a lymphoid-rich background admixed with a moderate amount of epithelial cells arranged in cohesive structures of variable size, including large sheets. The tumor cells resembled those of the corresponding biopsy, featuring mildly hyperchromatic nuclei with fine to vesicular chromatin. Lesional cells lacked keratinization, mitoses, or hyperchromasia. Our finding suggests that in nodal aspirates of patients with a history of sinonasal-type papillomas, especially those with prior malignant transformation or atypia, there should be consideration for the possibility of DEK::AFF2-related primary. When in doubt, DEK FISH of AFF2 immunohistochemistry should be performed for confirmation.

Liposarcoma Involving Serous Fluid Cavities-A Case Series Illustrating Clinical Implications and the Diagnostic Role of Exfoliative Cytology.

Introduction: Cytological diagnosis of sarcomas requires detailed cytomorphological assessment and integration of immunocytochemistry and/or molecular testing. The role of exfoliative cytology, as compared to aspiration cytology, is less understood. This case series describes well-differentiated/dedifferentiated liposarcomas in effusions, with cytomorphological features, ancillary test results and clinical outcomes detailed. Methods: A computerized search of the department pathology archives was performed for sarcomatous effusions with histological diagnosis or clinical history of well-differentiated/dedifferentiated liposarcoma. Clinical progress, cytology slides, immunocytochemistry and molecular test results were reviewed. Results: Six patients were identified. In 5 patients with clinical follow up, 4 (80%) were deceased within 5 months of malignant effusion. One patient was alive with 12 years disease-free survival after radical resection with adjuvant radiotherapy. Three patients showed dedifferentiation on histology, and high-grade (dedifferentiated) tumor cells were present in effusion cytology of 2 patients. Two showed well-differentiated components only on biopsy, but high-grade (dedifferentiated) tumor cells were identified in cytology. The high-grade tumor cells displayed marked nuclear irregularity, enlargement, size variation, with macronucleoli and multinucleation. Well-differentiated lipomatous components were demonstrated in 4 patients (66.7%), comprising of multivacuolated lipoblasts and atypical lipocytes. CDK4 and MDM2 immunoreactivity in all 3 cases with cell blocks, and CDK4 and MDM2 amplification in one were successfully demonstrated. Conclusion: Lipomatous and dedifferentiated components can be sampled and cytomorphologically identified on effusion fluids of liposarcomas, with sufficient cellularity for immunocytochemistry and molecular testing. Although generally associated with poor prognosis, long disease-free survival with sarcomatous effusion is possible with radical surgery and adjuvant treatment.

Detection of early (T1) lung cancers and lepidic adenocarcinomas in sputum and bronchial cytology.

BACKGROUND: The lung is an extensively epithelialized organ, producing ample exfoliated material for sputum and bronchial cytology. In view of the updates in the World Health Organization classification of early (T1/≤ 3 cm) lung cancer with respect to adenocarcinomas with lepidic pattern, this study retrospectively reviews sputum and bronchial cytology paired with resection-confirmed lung cancers. METHODS: A computerized search for all lung resection specimens of carcinomas over a 20-year period was performed. Cytologic diagnoses of corresponding sputum and bronchial cytology were classified into five-tiered categories (C1-insufficient/inadequate, C2-benign, C3-atypia, C4-suspicious and C5-malignant). Reports and slides of the resection specimen were reviewed for reclassification of T1 cancers. RESULTS: Totally 472 and 383 sputum and bronchial cytology specimens respectively were included. Sensitivity for T1 lesions on sputum cytology were 10.6 %, 2.1 % and 0.5 % at cutoffs of atypia/C3, suspicious/C4 and malignant/C5 categories, lower than bronchial cytology (35.1 %, 15.5 %, 8.1 %; p < 0.001). T1 lesions correlated with lower detection rates, whereas squamous cell carcinoma histology, larger size and bronchial invasion were associated with increased detection rates in sputum and bronchial cytology (p < 0.050). Detection rates for abrasive bronchial cytology (brushing) were overall higher (p = 0.018- < 0.001), but on subgroup comparison, non-abrasive (aspiration, lavage and washing) cytology demonstrated favorable trends (p = 0.063-0.088) in detecting T1 lesions. Adenocarcinomas with lepidic pattern had lower suspicious/C4 (p = 0.040) or above and malignant/C5 (p = 0.019), but not atypia/C3 or above (p = 0.517) rates. CONCLUSIONS: Most adenocarcinomas with lepidic pattern are only diagnosed as atypia/C3 on cytology. With its modest sensitivity, interpretation of negative and indeterminate cytology results mandates caution.

Application of algorithmic cytomorphological assessment and immunocytochemistry with the international system for reporting serous fluid cytopathology on pericardial fluid cytology.

AIMS: The international system for reporting serous fluid cytopathology (ISRSFC) set forth a five-tiered reporting system with comprehensive validation on pleural and peritoneal fluid cytology. An algorithmic approach for cytomorphological assessment and immunocytochemistry was also described in ISRSFC. Limited data on pericardial fluid are supportive but would benefit from further investigation. METHODS: Consecutive pericardial fluid cytology over a 4-year period was reviewed by multiple board-certified pathologists according to the ISRSFC. Cytomorphology and immunocytochemistry were assessed sequentially, with respective diagnostic performances computed and compared. Literature review was performed. RESULTS: In total 358 specimens, including 53 with immunocytochemistry available, were reviewed. There were 137 benign and 221 malignant (MAL) cases. The risks of malignancy were 23.5% non-diagnostic (ND), 29.2% negative for malignancy (NFM), 56.0% atypia of undetermined significance (AUS), 82.6% suspicious for malignancy (SFM) and 99.2% (MAL) for cytomorphological assessment, improving to 23.5% (ND), 29.1% (NFM), 56.8% (AUS), 78.9% (SFM) and 99.3% (MAL) incorporating immunocytochemistry. Ten cases (2.8%) received a change in diagnosis after review of immunocytochemistry. All revisions of diagnostic category were appropriate upgrades/downgrades referenced against clinical information. Cytomorphological typing was accurate for adenocarcinoma (n=81/83, 97.6%), while other carcinomas and lymphomas required immunocytochemistry. Certain subcategories within AUS and SFM pertaining to bland indeterminate epithelial cells or mucinous material were not seen for pericardial fluid. CONCLUSIONS: The ISRSFC shows robust diagnostic performance for pericardial fluid cytology. For pericardial effusion, disease composition and applicable cytological subcategories differ from its peritoneal and pleural counterparts. Incorporating immunocytochemistry by an algorithmic approach improves diagnostic accuracy. Cytomorphology is accurate for identifying adenocarcinomas, but further typing necessitates immunocytochemistry is necessary.

Detection rates and factors affecting thereof in endometrial hyperplasia, endometrial carcinoma, and cervical glandular lesions on cervical smear.

INTRODUCTION: Endometrial lesions are morphologically diverse and uncommon on cervical smears, with its detection rate and associated diagnostic categories uncharacterized. In this study, cervical smears matched to histologically proven endometrial hyperplasias and carcinomas were reviewed and compared with cervical in-situ-carcinomas/carcinomas, aiming to detail the diagnostic performance of cervical smears for upper tract and glandular lesions. METHODS: Pathology reports of cervical smears, hysterectomies, endometrial and cervical biopsies from 1995 to 2021 were retrieved. Diagnoses of cervical smears were matched to endometrial hyperplasias and carcinomas, or cervical carcinomas and reviewed. RESULTS: Totally 832 cervical smears (272 cervical carcinomas, 312 endometrial carcinomas, and 248 hyperplasias) were included. Considering all cytologic glandular diagnosis as positive, the detection rate of cervical adenocarcinoma-in-situ was the highest (64.3%), followed by cervical adenocarcinoma (63.8%), endometrial carcinoma (31.7%), and hyperplasia (with atypia-8.5%; without atypia-2.3%) (p < 0.001). Endometrial hyperplasia was most often diagnosed as atypical squamous cells of undetermined significance (ASCUS) (5.0%) or atypical glandular cells, not otherwise specified (3.6%) without indication of endometrial origin. For endometrial carcinomas, higher FIGO grading and endocervical involvement were associated with higher detection rates across all diagnostic categories (p = 0.002-0.028). High FIGO grade was associated with suspicious/favor neoplastic (C4) (31.1%vs10.3%, p < 0.001) and carcinoma (C5) (17.8% vs. 5.6%, p = 0.005) categories, but not for all glandular diagnoses combined (33.3% vs. 31.0%, p = 0.761). CONCLUSION: Detection rates for endometrial lesions are lower than cervical lesions but not insignificant. Endometrial hyperplasia should be recognized as a differential of human papilloma virus-negative ASCUS and prompt consideration of investigation of the upper genital tract.

Bronchial cytology of pulmonary adenoid cystic carcinoma - A multi-institute series with emphasis on immunocytochemistry.

BACKGROUND: Pulmonary adenoid cystic carcinoma (AdCC) is a central and superficial primary lung neoplasm, well-suited for sampling by bronchial cytology. This study aims to review the cytologic features of pulmonary AdCC on bronchial cytology, and to report an experience of applying immunocytochemistry on this rare entity. METHODS: A multi-institute review of bronchial cytology specimens from histologically proven pulmonary AdCCs was performed. Published cases of bronchial cytology of pulmonary AdCC were reviewed. The cytologic features and immunocytochemical profile for pulmonary AdCC was summarized and compared with pertinent differentials. RESULTS: A total of 16 specimens from eight patients were retrieved. The initial cytologic diagnoses were negative (n = 7), atypia (n = 6), suspicious (n = 2) and AdCC (n = 1). Retrospective review showed eight bronchial cytology specimens (including five cases of atypia) with tumor cells present. The tumor cells displayed small basaloid nuclei with occasional small nucleoli, mild nuclear atypia, and scanty cytoplasm. Architectural patterns observed included clusters, tubules, solid sheets, three-dimensional balls, papillary-like fronds, and complex cribriform structures. Basement-membrane-like material, free or associated with tumor cells, were seen in all cases. Immunocytochemistry was performed in one specimen. MYB was positive. TTF-1, synaptophysin and chromogranin were negative. Epithelial and basal markers demonstrated a dual cell population. Literature review yielded 28 cases. Cytologic features described were similar except for cytoplasmic vacuolation in one case. CONCLUSION: Basement membrane-like material is specific for AdCC. MYB positivity, TTF-1 and neuroendocrine marker negativity, support a diagnosis of AdCC. Other immunocytochemistry and cytologic features overlap significantly with adenocarcinoma and small cell carcinoma of lung.

WT1 as a myoepithelial marker: a comparative study of breast, cutaneous, and salivary gland lesions.

WT1 immunostain is expressed in various benign and malignant neoplasms, as well as normal myoepithelial cells. WT1 shows differential expression in non-neoplastic, benign, and malignant neoplastic myoepithelial cells of the salivary gland. In this study, WT1 immunostain and other myoepithelial markers were compared to investigate the value of WT1 as a myoepithelial marker, and to delineate the expression profile of WT1 in nonsalivary gland myoepithelial cells. WT1, p63, and calponin immunostains were performed on normal and lesional tissues from the breast (adenosis, sclerosing adenosis, lactating adenoma, nipple adenoma, tubular adenoma, adenomyoepithelioma, and adenoid cystic carcinoma [ACC]), skin (cutaneous mixed tumor, hidradenoma, spiradenoma, and ACC), and salivary gland (pleomorphic adenoma and ACC). The stained slides were digitized and orientated with H&E images and assessed simultaneously using QuPath. A total of 129, 58, and 56 breast, cutaneous, and salivary gland lesions, respectively, were included. There was poor agreement between WT1-p63 and WT1-calponin (κ < 0.1) in all organs, with absence of WT1 expression in normal salivary gland myoepithelium and most ACCs. There were no significant differences in WT1 expression in myoepithelial cells in normal breast tissue and benign breast neoplasms. Compared to pleomorphic adenomas, cutaneous mixed tumors showed lower WT1 expression (P < .001). WT1 is a less sensitive myoepithelial marker than calponin and p63. However, its unique pattern of expression in salivary gland primary for pleomorphic adenomas/cutaneous mixed tumor can favor a diagnosis of benign salivary gland tumors, particularly in small biopsy specimens.

Number Needed to Diagnose in Malignant Ascites: Effects of Volume, Repeating Collection, and Primary Malignancy on Diagnostic Performance in Peritoneal Fluid Cytology.

INTRODUCTION: Volume recommendations of 80-200 mL have been proposed for peritoneal fluid cytology. While cutoffs are impractical when volume is limited by the amount present and disease factors, collections, however, can be repeated. This study addresses adequacy and number needed to diagnose by comparing diagnostic agreement to volumes in single specimens, total volumes collected daily, and within admissions. The diagnostic yield of repeating collection within a single day, admission, and throughout admissions of a patient's lifetime was also investigated. METHODS: Peritoneal fluid cytology specimens over a 27-year period were retrieved and matched by collection date, admission number, and patient number. Case notes were reviewed to establish all cases of malignant ascites. RESULTS: In total, 19,392 specimens from 14,327 admissions and 11,089 patients were retrieved, with 1,531 patients confirmed with malignant ascites. Agreements between cytologic diagnoses within the same day and admission were high (κ > 0.8). Fluid volume increased with grade of cytologic diagnosis (p < 0.001), and greater volume was associated with higher discordance (p < 0.05). Specimens of 60-100 mL showed the best diagnostic concordance. To achieve a 99.5% diagnostic rate, three sequential aliquots, collections from two different days in an admission, or three admissions within a lifetime are required. The diagnostic yield of one aliquot within batches from the same day was only 88.9%. Gastrointestinal (p = 0.040), gynecologic (p = 0.005), and lung (p < 0.001) malignancies required the least repeats for diagnosis. CONCLUSIONS: Omission of any fluid from laboratory submission is strongly discouraged. As a simple rule, three repeats are necessary for excluding malignant ascites.

Tubular Adenomas of the Breast Are Cytologically Distinct from Fibroadenomas.

INTRODUCTION: Increasing molecular evidence indicates that tubular adenoma of the breast is distinct from fibroepithelial lesions, leading to its reclassification as an epithelial tumor in the 5th World Health Organization classification of tumors of the breast. However, tubular adenoma remains poorly characterized on fine-needle aspiration cytology (FNAC) and often not distinguished from fibroadenomas. In this study, the largest cohort, to date, of histologically confirmed aspirates of tubular adenomas were reviewed and compared with aspirates of fibroadenomas. Findings from this study further define the cytological features of tubular adenoma and allow differentiation from fibroadenoma. METHODOLOGY: Aspirates of histologically confirmed tubular adenomas were reviewed for features of the background, myoepithelial, epithelial, and stromal components and then compared to a cohort of aspirates of fibroadenomas. RESULTS: Totally, 43 (tubular adenoma) and 94 (fibroadenoma) aspirates were included. Tubular adenomas displayed moderate epithelial cellularity with high cohesiveness, with stromal fragments containing epithelium. Tubules are more common in tubular adenomas (p = 0.009) and "tubular fragments" (tissue fragments containing multiple tubular structures with/without stroma) is a pathognomonic feature of tubular adenoma (p < 0.001). Calcification and fibrocystic changes were variably seen (4.65-13.5%) but without difference to fibroadenomas (p > 0.05). Cytomorphologically malignant features and mitoses were absent in all aspirates of tubular adenoma. Presence of tubules and stromal fragments were independent factors associated with tubular adenomas, whereas a predominance of large epithelial fragments and naked stromal fragments were associated with fibroadenomas. CONCLUSION: Tubular adenomas are not only histologically and molecularly separate from fibroepithelial lesions but also a distinct entity on FNAC.

A comparative study of diagnostic accuracy in 3026 pleural biopsies and matched pleural effusion cytology with clinical correlation.

BACKGROUND: Pleural effusion can be caused by a wide range of benign and malignant conditions. Pleural biopsy and effusion cytology represent two key methods of pathological diagnosis. To compare the performance these two methods, a large cohort of matched pleural biopsy and effusion cytology with clinical follow-up was reviewed. METHODS: Pleural biopsies and effusion cytology specimens over a period of 18 years were retrieved. Cytology specimens collected within 7 days of pleural biopsy were matched. Reports were reviewed, and the cause for pleural effusion was determined by hospital disease coding and clinical data. RESULTS: Totally, 3026 cases were included. The leading cause of benign effusion was tuberculosis (n = 650). Malignant pleural effusion (MPE) was more common in older females (p < 0.001) and mostly due to lung cancer (n = 959), breast cancer (n = 64), and mesothelioma (n = 48). The inadequate/insufficient (B1/C1) rate of biopsy was higher than cytology (15.6% vs. 0.3%) but the rates for other diagnostic categories were similar. Biopsy and cytology showed a correlation coefficient of 0.315, improving to 0.449 when inadequate/insufficient (B1/C1) cases were excluded. The ROM for benign cytology (C2) was lower than biopsy (B2) (p < 0.001). Compared with biopsy, the diagnostic accuracy was higher in cytology overall and for metastatic carcinomas (p < 0.001) but lower for hematolymphoid malignancies (p = 0.014) and mesotheliomas (p = 0.002). CONCLUSIONS: These results suggest that effusion cytology may be better for confirming benignity and diagnosing carcinomatous MPE. In these cases, pleural biopsy may be withheld to reduce procedural risks. However, for suspected hematolymphoid malignancies and mesothelioma, biopsy should be considered.