“Dense Squamoid Cytoplasm” and “Cellular Swirls” on Fine Needle Aspiration Cytology: Useful Ancillary Findings in the Diagnosis of Papillary Thyroid Carcinoma
Michio Shimizu, Tomoko Saze, Atsushi Sasaki, Shin-ichi Murata, Masanori Yasuda. Saitama Medical University, Saitama International Medical Center, Hidaka, Saitama, Japan
Background: “Dense squamoid cytoplasm” in cases of papillary thyroid carcinoma is described in some cytology textbooks, and “cellular swirls” are a recently recognized diagnostic clue to papillary carcinoma; however, their diagnostic significance has not been fully evaluated.
Design: The subjects were 50 cases of aspiration biopsy specimens of papillary carcinoma of the thyroid, which were histologically confirmed. In addition, 15 cases of adenomatous goiter, 10 cases of follicular neoplasm, 8 cases of medullary carcinoma and 2 cases of undifferentiated carcinoma were selected as control cases.
Results: Dense squamoid cytoplasm was observed in 25 cases (50%) of the papillary carcinoma. However, only one case of undifferentiated carcinoma revealed dense squamoid cytoplasm among the control cases. Dense squamoid cytoplasm was found as a sheet-like pattern or mildly overlapping pattern. Dense squamoid cells were slightly bigger than the usual follicular epithelial cells. The cytoplasm was polygonal and dense, and it had a distinct cell boundary. In addition, anisonucleosis was remarkable, and the nucleus was two to three times bigger than that of normal follicular epithelial cells. On the other hand, cellular swirls were found in 12 cases (24%) of the papillary carcinoma cases. Oval nuclei were arranged evenly in a swirl-like pattern. Control cases did not show cellular swirls.
Conclusions: Dense squamoid cytoplasm and cellular swirls were found in 50% and 24% of the cases of papillary carcinoma of the thyroid, respectively. Although both findings are not frequently observed, they are easy to identify at low magnification; therefore, they can be used as ancillary findings and deserve to be given more attention.
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 68, Wednesday Afternoon