Cribriform-morular variant of papillary thyroid carcinoma.

Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is a rare morphologic entity. This tumor is usually associated with familial adenomatous polyposis (FAP), but rarely may be sporadic. This neoplasm commonly occurs in young females. The majority of patients present with gradually enlarging painless neck mass. There is no specific imaging finding of CMV-PTC, and the diagnosis is exclusively made on pathologic examination. A multitude of cytologic features of CMV-PTC are described, which includes hypercellularity, cribriform pattern, papillary arrangement of tall columnar cells, morules, spindle cells, clear and ground-glass nuclei, hyaline material, hemosiderin-laden histiocytes, and absence of colloid in the background. CMV-PTC is histologically characterized by the papillary growth of tall columnar cells, cribriform pattern without colloid, spindle cells, squamoid morules, and nuclear clearing. The immunoreactivity for beta-catenin and biotin-positive nuclear clearing may indicate CMV-PTC. Total thyroidectomy for familial or lobectomy for sporadic cases is usually the treatment for CMV-PTC. It carries a better prognosis than the other aggressive variants of papillary thyroid carcinoma. In this review, we discuss the current knowledge on CMV-PTC and its clinical relevance.