Fine-needle aspiration cytology of the solid variant of XXXX : A study of 13 cases with clinical, histologic, and ultrasound correlations.

@entity3557 @entity1 @entity5953 @entity8958 @entity23275 @entity5 @entity3 @entity259 @entity2750
BACKGROUND: The solid variant of @entity3557 (SVPTC) comprises approximately 3% of @entity259 , and there are conflicting reports about its behavior in the literature. The cytology of SVPTC is limited to 3 single case reports, a review article, and a monograph. We present the first cytologic study of SVPTC. METHODS: Fine-needle aspiration smears obtained with ultrasound guidance from 13 @entity1 with histologically pure SVPTC were reviewed, and the cytologic features recorded. Ultrasound images were retrieved from radiology and were correlated with low-power histology images. Intratumor vascularity on Doppler imaging was correlated with cellularity in cytology samples. RESULTS: Three cytomorphologic patterns of SVPTC were identified: cohesive, syncytial-type tissue fragments; microfollicles/trabeculae; and dyshesive single cells. @entity5953 SVPTCs in the first group were encapsulated without invasion. Two of 6 SVPTCs in the second group had a single lymph node @entity3 ; 4 were encapsulated, and 2 had pushing borders. Ultrasound images in the first and second SVPTC groups were similar, with the majority revealing a well defined, solid nodule with minimal intranodular vascularity. All 4 SVPTCs in the third group had infiltrative borders; and, with the exception of one 0.8-cm @entity5 , all had multiple lymph node @entity3 . Ultrasound in the third group revealed irregular borders. @entity8958 / @entity2750 and @entity8958 / @entity23275 mutations were found in 2 cases of the third group. CONCLUSIONS: SVPTCs are heterogeneous @entity5 . The cohesive, syncytial tissue-fragment pattern can be recognized as SVPTC in smears and is associated with encapsulation and indolent behavior. The microfollicular/trabecular pattern is indistinguishable from that of the follicular variant of @entity3557 and has intermediate behavior. The dyshesive single-cell pattern correlates with infiltrative @entity5 growth and may not be unique to SVPTC. @entity5 ( @entity5 Cytopathol) 2015.    2015 American @entity5 Society.
