Cribriform-Morular Variant of Papillary Thyroid Carcinoma: A Report of Two Cases

ABSTRACT

Cribriform-morular variant of papillary thyroid carcinoma is an unusual and peculiar subtype of papillary thyroid carcinomas. It occurs both sporadically and in association with familial adenomatous polyposis. We report here on two cases of cribriform-morular variant of papillary thyroid carcinoma in a 33-year-old woman and in a 21-year-old woman. On gross examination, both cases were multicentric. The first case showed two well-encapsulated yellow solid masses in the right (2.0 cm) and the left lobes of the thyroid gland (0.5 cm). The second case showed four well-encapsulated gray-white solid lobulating masses and nodules in the right (4.5 and 1.2 cm) and the left lobes (1.1 and 0.8 cm) of the thyroid gland. Microscopically, both cases exhibited an intricate blending of papillary, cribriform, trabecular, spindle, and solid patterns of growth with morular areas. Typical nuclear features of papillary carcinomas were focally seen. Immunohistochemically, the tumor cells were positive for thyroglobulin, thyroid transcription factor-1 (TTF-1), and beta-catenin, but were negative for calcitonin.