Ovarian endometrioid adenocarcinoma associated with steroidogenic foamy stromal cells

A case of 69-year-old woman with endometrioid adenocarcinoma of the ovary with functioning stromal cells is presented. The patient complained of genital bleeding. Endometrial curettage revealed endometrial hyperplasia. Pre-operative levels of serum estradiol and progesterone were elevated, and serum gonadotropin levels were suppressed. The surgical specimen contained fist-sized, bilateral, solid, ovarian tumors and a mildly enlarged uterus. Histologically, the proliferating, atypical, columnar cancer cells resembled early secretory, endometrial epithelial cells with subnuclear vacuolation, and there were clusters of fat-laden foamy cells in the stroma. Immunohistochemically, the cancer cells were positive for cytokeratin and progesterone receptor but negative for estrogen receptor. The stromal foamy cells were immunoreactive for vimentin, progesterone receptor, P450 side chain-cleavage, 3 beta-hydroxysteroid dehydrogenase, and adrenal 4-binding protein. Immunoreactivities of P450c-17 alpha hydroxylase and aromatase were only focally observed. These findings indicated that the stromal cells were steroidogenic and mainly produced progesterone. The cancer cells that expressed progesterone receptors showed morphologic changes in response to hormonal stimulation.