Most hormonally active ovarian tumors belong to the category of tumors of the gonadal stroma. These account for less than 5% of all ovarian tumors. About two-thirds of tumors of the gonadal stroma produce steroid hormones. The pathologic secretion of estrogenic or androgenic hormones leads to specific effects on the hormone-sensitive target organs. The clinical manifestations depend on both the amount of hormones secreted and the age of the patient. Tumors of the gonadal stroma are potentially malignant, ranging between noninvasive (borderline) tumors and invasive epithelial tumors of the ovary. Besides the specifically steroid hormone-producing tumors, a wide variety of ovarian tumors other than those in the stroma of the ovary and steroid cell tumors may be hormonally active as the result of an increase in and/or stimulation of nonneoplastic ovarian stromal cells within or adjacent to the tumor.
