Histologic subtyping of non-small cell lung carcinoma (NSCLC) is important because the efficacy of new treatments depends on tumor histologic features. We assessed the diagnostic accuracy of classification of lung adenocarcinoma and squamous cell carcinoma (SCC) on cytologic and biopsy specimens based on cytomorphologic studies alone or in combination with ancillary studies compared with resection specimens. Compared with adenocarcinoma, the diagnosis of SCC was based more often on cytomorphologic studies alone (139/185 [75.1%] vs 107/263 [40.7%]). Significantly increased use of immunohistochemical studies in cytology was noted after introduction of targeted lung carcinoma therapies (22/156 [14.1%] for adenocarcinoma and 5/46 [11%] for SCC from 2000-2004 vs 134/156 [85.9%] for adenocarcinoma and 41/46 [89%] for SCC from 2005-2010). Use of immunohistochemical studies resulted in increased diagnostic accuracy for adenocarcinoma (56% [44/78] from 2000-2004 vs 83.2% [154/185] after 2005) but not for SCC (77% [57/74] before 2004 vs 73.9% [82/111] from 2005-2010). Adenocarcinoma showed high expression of cytokeratin (CK)7 (146/146 [100%]), thyroid transcription factor-1 (131/152 [86.2%]), surfactant A (29/36 [81%]), and periodic acid-Schiff with diastase (69/86 [80%]). All SCCs were positive for CK5/6 and p63. Use of immunohistochemical studies on cytologic cell blocks may improve classification of NSCLC.

BACKGROUND The interpretation of atypical glandular cells (AGC) in Papanicolaou (Pap) tests and screening for glandular neoplasia remain challenging. METHODS Pap tests with an AGC interpretation from January 2008 to December 2013 were retrieved from a pathology database, and cases with histologic follow‐up within 1 year were included in the study. RESULTS There were 589,830 Pap tests during the study period, and 3709 cases (0.6%) were reported as AGC, which included the following: AGC, not otherwise specified (52.0%); atypical endocervical cells (28.0%); and other categories. There were 3007 cases (81.1%) with histologic follow‐up results within 1 year. Cervical intraepithelial neoplasia 2/3 (CIN2/3), cervical adenocarcinoma in situ (AIS)/adenocarcinoma, and endometrial carcinoma were identified in 5.6%, 1.9%, and 5.5% of cases, respectively. Glandular neoplasia was more likely to be identified in cases with pure AGC subcategories than cases with AGC and squamous abnormalities. Endometrial neoplasia was more likely to be identified in cases with atypical endometrial cells than other categories. Overall, the most common severe abnormality on histologic follow‐up was CIN2/3. Although CIN2/3 was the most common severe lesion in patients younger than 30 years (10.0%) and in patients aged 30 to 49 years (6.4%), endometrial carcinoma was the most common lesion in women who were 50 years old or older (13.7%). Endocervical glandular lesions (AIS and adenocarcinoma) occurred in only 1.9% of women. CONCLUSIONS AGC subtypes and ages significantly affect histological follow‐up results; 90.5% of cases with carcinoma on histologic follow‐up were either endometrial or metastatic carcinoma. This study supports the recommendation that women with AGC Pap test results should be followed up with both endocervical and endometrial sampling. Cancer Cytopathol 2016;124:589‐95. © 2016 American Cancer Society.

Introduction: Extracranial meningiomas may infrequently be encountered as ectopic or metastatic tumors. Their rarity and unique cytomorphology often pose significant diagnostic dilemmas. The aim of this study was to report our experience with a series of ectopic and metastatic meningiomas, characterizing their cytomorphology with histological correlation. Materials and Methods: A retrospective analysis involving 13 patients with cytological preparations from extracranial meningiomas was performed. Cytology cases were correlated with available surgical resection specimens. Data regarding clinical findings, tumor information, cytomorphology, follow-up histological features and immunohistochemistry were recorded and analyzed. Results: There were 5 cases with metastases and 8 ectopic meningiomas. Metastases occurred in the scalp/skull, lung, paraspinal soft tissue and liver. Primary ectopic meningiomas were located in the paranasal sinuses and ear, orbit and neck. Cytomorphological features characteristic of meningiomas were identified in the majority of samples including tightly cohesive clusters of spindled cells, whorls, intranuclear inclusions, nuclear grooves and psammomatous calcification. Unusual cytomorphological features identified in only a few cases included epithelioid cell predominance, abundant inflammatory cells, small-cell change, papillary structures and pseudoacinar growth. Metastatic tumors exhibited more nuclear atypia and occasionally mitoses or necrosis. Meningiomas were shown to be immunoreactive for epithelial membrane antigen, pancytokeratin and vimentin. Conclusion: Although rare, extracranial meningiomas can be encountered in cytologic specimens and should be included in the differential diagnosis when characteristic morphological features of meningiomas are seen. Cytopathologists should be aware that these lesions could be mistaken for other tumors, especially when confounded by atypia and unusual cytomorphological features.