Small cell carcinoma of the ovary of the hypercalcemic type is a highly aggressive neoplasm that typically affects girls and young women. The clinical presentation is nonspecific except for its association with paraendocrine hypercalcemia in two thirds of the cases that only rarely causes clinical manifestations. At the time of surgery, extraovarian spread is present in 50% of the patients. Grossly, the tumors are solid with a variable cystic component and extensive areas of necrosis. On microscopic examination, the neoplastic cells commonly show a diffuse growth pattern; however, nests, clusters, or cords may be seen. Follicle-like spaces are present in most neoplasms. Although the tumor cells are typically small, up to 50% of tumors contain large cells with abundant eosinophilic cytoplasm that may contain hyaline globules. In up to 8% of the cases, mucinous differentiation may be seen. The tumors frequently express keratin and epithelial membrane antigen, as well as vimentin, WT-1, CD10, calretinin, and p53 and are typically negative for inhibin, CD99, chromogranin, desmin, and thyroid transcription factor 1 (TTF-1). These immunohistochemical markers help in differentiating small cell carcinoma of the hypercalcemic type from granulosa cell tumors and other small round cell tumors involving the ovary, including small cell carcinoma of the pulmonary type. The immunohistochemical profile and electron microscopic findings favor an epithelial origin of this neoplasm. Prognosis is dismal despite aggressive therapy, with an overall survival rate of 10%, which increases to 30% when only stage I tumors are considered. Although surgery is the main treatment option, some reports indicate a possible adjuvant role of chemotherapy in the treatment of some patients, including those with advanced-stage disease.
From the Pathology Department, Massachusetts General Hospital, Boston, Massachusetts.
Reprints: Esther Oliva, MD, Associate Pathologist/Associate Professor, Pathology Department, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114. E-mail: firstname.lastname@example.org.