MRI appearance of ruptured corpus luteum.

A 20-year-old woman was admitted complaining of lower abdominal pain. Transabdominal ultrasound revealed a fluid collection in the pouch of Douglas and an irregularly shaped ovary with cystic lesions. Malignant cystic mass of the right ovary was highly suspected from the ultrasound findings. Transvaginal peritoneal centesis yielded a bloody fluid, but the pregnancy test was negative. On the third day of admission, menstruation began. MR examination performed four days after the initial onset of pain showed a subacute hematoma just adjacent to the right ovary, and segmental interruption of the right ovarian cortex. Based on these MR findings and the patient's history, subacute hemorrhage from the right ovarian corpus luteum was suspected, and this was confirmed with surgical exploration.