Estrogen synthesizing rare malignant Brenner tumor of the ovary with the presence of progesterone and androgen receptors in the absence of estrogen receptors.

A case of a malignant Brenner tumor of a postmenopausal woman presenting with vaginal bleedings is described. Clinical and laboratory findings demonstrated estrogenic secretory function and action. The presence of aromatase activity based on in vitro tumor microsomal metabolism of androgen to estrogen is described. Tumor cytosol contained progestin and androgen binding components in the absence of estrogen binding activity. Estrogen binding activity was undetectable both by biochemical as well as histochemical assays.