Dilated rough endoplasmic reticulum corresponding to septate cytoplasmic vacuoles in papillary thyroid carcinoma

Septate cytoplasmic vacuoles, which are one of the cytologic findings chara cteristic of papillary thyroid carcinoma, are small, uniform, and well-defi ned vacuoles, with defined strands of cytoplasm separating them. We report on a case with histologic. and ultrastructural findings corresponding to se ptate cytoplasmic vacuoles, which have not been previously described. The p atient was a 51-yr-old man with a mass in the left anterior of the neck, me asuring 4.0 x 3.5 cm in diameter Aspiration cytology smears revealed findin gs typical of papillary thyroid carcinoma, including papillary tissue fragm ents, intranuclear inclusions, nuclear grooves, powdery chromatin, and psam moma bodies. The tumor cells which were located at the periphery of small t hree-dimensional clusters, and others which showed a sheet-like arrangement , demonstrated uniform, small vacuoles in relatively abundant, dense cytopl asm. Histologically, a small number of papillary thyroid carcinoma cells wi th multiple vacuoles were observed, which were limited to the hobnail-shape d cells located at papillary configurations or floating turner cells within the papillary lumen. Ultrastructurally, the hobnail-shaped tumor cells dem onstrated various-sized dilated rough endoplasmic reticulum and rich hetero chromatin. We emphasize that septate cytoplasmic vacuoles correspond to dil ated rough endoplasmic vacuoles and are probably related to degenerative ch anges. Diagn. Cytopathol. 2000; 23:351-353. (C) 2000 Wiley-Liss, Inc.