A giant pedunculated leiomyoma with cystic degeneration 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 41-year-old nulliparous woman presented with a history of lower abdominal pain 20 days and distension for a period of approximately 10 years. The patient's personal history revealed difficulty in walking, tiredness and 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-oopharectomy. The histology revealed a leiomyoma with extensive cystic degeneration. 50% uterine fibroids are asymptomatic. As leiomyomas enlarge, they can outgrow their blood supply, resulting in various types of degeneration. Hyalinization is the most common type of degeneration, occurring in up to 60% of cases. Cystic degeneration, observed in about 4% of leiomyomas, may be considered extreme sequelae of edema. Typical appearances of leiomyomas are easily recognized on imaging. However, the atypical appearances that follow degenerative changes can cause confusion in diagnosis. Pedunculated leiomyomas should be considered in the differential diagnosis of a multilocular and predominantly cystic adnexal mass