Cribriform morular variant of papillary thyroid carcinoma: Cytomorphology, differential diagnosis and diagnostic implications in patients with adenomatous polyposis coli

Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC), which has a better prognosis, is seen mostly in the setting of familial adenomatous polyposis (FAP). The cytomorphology of CMV-PTC is diverse; hence, it could be mistaken for other thyroid neoplasms with bad prognostic outcome. This case is of a 24-year-old female diagnosed with polyposis coli found to have thyroid nodules at screening ultrasonography. Aspirated thyroid smears were hypercellular with epithelial cells arranged in monolayer sheets, papillae with discohesion, and spindling of cells at the edges, cribriform clusters, and cell morules. Individual cell morphology ranged from polygonal, tall columnar to spindle cells. Nuclei were round-to-oval with coarse chromatin, indistinct nucleoli, and mitotic figures. Nuclear inclusions and grooves were rare and colloid was sparse. Cytomorphology was suspicious, however, was not classical of CMV-PTC documented so far. Subsequent histology confirmed a CMV-PTC.