Composite mucinous and granulosa-cell tumor of ovary: case report of a unique neoplasm.

A 63-year-old woman presented with signs and symptoms of an estrogen-producing ovarian tumor. At laparotomy, this tumor proved to be a multilocular right ovarian mass 20 cm in greatest diameter. The cystic spaces were lined by typical benign mucinous epithelium of the endocervical type, while the greatly thickened cyst walls contained a diffuse proliferation of granulosa cells. These two disparate components were intimately mixed at a variably complex interface to form a composite tumor. While composite tumors showing sex cord-stromal and epithelial elements are well documented, they have all, to date, been of moderately to poorly differentiated androblastomatous or Sertoli-Leydig cell type, associated with heterologous mucinous elements of intestinal differentiation. The combination of granulosa-cell tumor with mucinous elements of endocervical or müllerian type has not hitherto been reported and is of uncertain histogenesis.