Cribriform-morular variant of papillary thyroid carcinoma--cytological and immunocytochemical findings of 18 cases.

The purpose of this article was to describe cytologic findings of cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) in detail, to review previously reported cases, and to emphasize the diagnostic significance of this subtype. We examined 19 ultrasound-guided fine needle aspiration (FNA) specimens from 18 CMV-PTC patients. Cytologic features of CMV-PTC were as follows, (1) hypercellularity, (2) papillary arrangement composed of tall columnar cells, (3) cribriform pattern, (4) morules, (5) spindle cells, (6) obscure ground-glass nuclei, (7) peculiar nuclear clearing (PNC), (8) foamy or hemosiderin-laden histiocytes, (9) hyaline materials, (10) absence of colloid in the background. The nuclear and cytoplasmic immunoreactivity of beta-catenin and biotin-positive PNC can indicate CMV-PTC. We believe that cytologic diagnosis of CMV-PTC is possible and it may lead to the early detection of polyposis coli.