Polycystic ovaries and stromal hyperthecosis

Polycystic ovarian disease (PCOD; formerly termed Stein-Leventhal syndrome) affects 3% to 6% of reproductive-age women. The central pathologic abnormality is numerous cystic follicles or follicle cysts, often associated with oligomenorrhea. Women with PCOD have persistent anovulation, obesity (40%), hirsutism (50%), and, rarely, virilism.72,73

Morphology. The ovaries are usually twice normal size and have a smooth, gray-white outer cortex studded with subcortical cysts 0.5 to 1.5 cm in diameter. On histologic examination, there is a thickened, fibrotic superficial cortex beneath which are innumerable follicle cysts associated with hyperplasia of the theca interna (follicular hyperthecosis) (Fig. 22-34). Corpora lutea are frequently but not invariably absent.

The initiating event in PCOD is not clear. Increased secretion of luteinizing hormone may stimulate the theca-lutein cells of the follicles, to produce excessive androgen (androstenedione), which is converted to estrone. For years, these endocrine abnormalities were attributed to primary ovarian dysfunction because large wedge resections of the ovaries sometimes restored fertility. It is now believed that a variety of enzymes involved in androgen biosynthesis are poorly regulated in PCOD. Recent studies link PCOD, like type 2 diabetes, to insulin resistance. Treatment of the insulin resistance sometimes results in resumption of ovulation.74

Stromal hyperthecosis, also called cortical stromal hyperplasia, is a disorder of ovarian stroma most commonly seen in postmenopausal women, but it may blend with PCOD in younger women. The disorder is characterized by uniform enlargement of the ovary (up to 7 cm), which has a white to tan appearance on sectioning. The involvement is usually bilateral and microscopically shows hypercellular stroma and luteinization of the stromal cells, which are visible as discrete nests of cells with vacuolated cytoplasm. The clinical presentation and effects on the endometrium are similar to those of PCOD, although virilization may be striking.72

A physiologic condition mimicking the above syndromes is theca lutein hyperplasia of pregnancy. In response to pregnancy hormones (gonadotropins), proliferation of theca cells and expansion of the perifollicular zone occurs. As the follicles regress, the concentric theca-lutein hyperplasia may appear nodular. This change is not to be confused with true luteomas of pregnancy (see below).

Ovarian Tumors

T here are numerous types of ovarian tumors, and overall they fall into benign, borderline, and malignant categories. About 80% are benign, and these occur mostly in young women between the ages of 20 and 45 years. Borderline tumors occur at slightly older ages. Malignant tumors are more common in older women, between the ages of 45 and 65 years. Ovarian cancer accounts for 3% of all cancers in females and is the fifth most common cause of death due to cancer in women in the United States. Among cancers of the female genital tract, the incidence of ovarian cancer ranks below only carcinoma of the cervix and the endometrium. In addition, because most ovarian cancers are detected when they have spread beyond the ovary, they account for a disproportionate number of deaths from cancer of the female genital tract.