Malignant Brenner tumor of the ovary with transformation to trabecular carcinoid: an immunocytochemical and electron microscopic study.

Ovarian Brenner tumors are typically of surface epithelial-stromal origin; however, cases associated with mature cystic teratoma and/or struma ovarii possibly have a teratomatous derivation. Although argyrophil cells have been described in ovarian Brenner tumors and in urinary bladder epithelium, we are not aware of any previous reports of carcinoid arising from a malignant Brenner tumor of the ovary. In this study, we describe an 85-year-old woman who had a low-grade malignant Brenner tumor with progressive proliferation of neuroendocrine cells and transformation to trabecular carcinoid as demonstrated by immunocytochemistry and electron microscopy.