Dysgerminoma in the differential diagnosis of hydatidiform mole.

Serum measurements of beta-human chorionic gonadotropin (beta-hCG) for pregnancy tests are now positive at very low levels (25 mIU/mL). Sonography is the diagnostic method of choice for patients with the possibility of intrauterine trophoblastic disease. A case is reported in which ultrasound confused an ovarian neoplasm for a hydatidiform mole; a low level of hCG produced by the dysgerminoma corroborated the diagnosis. The tumor with syncytiotrophoblastic giant cells is described, and a differential diagnosis for minimally elevated hCG is discussed. This case represents an example of dysgerminoma presenting with ascites (stage IC).