Unilateral luteoma of pregnancy mimicking a malignant ovarian mass on magnetic resonance and ultrasound.

Luteoma of pregnancy is a rare, tumorlike ovarian mass that develops during pregnancy and regresses after delivery. Generally, these masses are discovered incidentally during cesarean delivery or tubal ligation. Some of these patients will develop hirsutism or virilization during late pregnancy with or without fetal masculinization due to circulating androgens. The imaging features of this entity have been only rarely reported. An incidentally discovered luteoma of pregnancy in a 23-year-old patient during routine obstetric ultrasound is described and the image features in ultrasound and magnetic resonance (MR) imaging are discussed and compared with other studies. The patient underwent surgery to extract this mass considering the imaging findings were suspicious for neoplasia and the size and location could have potentially caused dystocia. This type of mass can mimic ovarian neoplasia and a correlation with imaging and laboratory findings can avoid an unnecessary surgical procedure during pregnancy.