A giant cystic leiomyoma mimicking an ovarian malignancy

Leiomyoma of the uterus is the most common type of tumor affecting the female pelvis and arises from uterine smooth muscle. The size of leiomyomas varies from microscopic to giant; giant myomas are exceedingly rare. We report an unusual case of a large, cystic, pedunculated uterine leiomyoma mimicking a primary malignant ovarian tumor on sonography and CT.

A 58-year-old postmenopausal nulliparous woman presented with a history of lower abdominal pain and distension for a period of approximately 12 months. The patient's personal history revealed difficulty in walking, tiredness and recent weight gain of approximately 25kg. Sonography and CT examination showed a large mass that filled the abdomen. A preoperative diagnosis of a primary malignant ovarian tumor was made. The patient underwent laparotomy, total hysterectomy and bilateral salpingo-ooferectomy. The histology revealed a leiomyoma with extensive cystic degeneration.

The current established management of uterine fibroids may involve expectant, surgical, or medical management or uterine artery embolization or a combination of these treatments. A surgical approach is preferred for management of giant leiomyomas.

Pedunculated leiomyomas should be considered in the differential diagnosis of a multilocular and predominantly cystic adnexal mass.