Preperitoneal lipoleiomyoma of the abdominal wall in a postmenopausal woman

Objective: Extrauterine leiomyomas are rare events. These tumors may be easily misdiagnosed as ovarian tumors at the clinical investigation. We present the first case of an otherwise healthy postmenopausal woman, hysterectomized 20 years ago, who developed a preperitoneal lipoleimoyoma in the 30-year-old scar of a Pfannenstiel incision. The patient received continuous hormone replacement therapy (HRT) for 5 years with 1.25 mg conjugated estrogen and 5 mg medrogeston per day. Methods: In sections of the tumor, immunohistochemical reactions with antibodies against actin, desmin, vimentin, estrogen and progesterone receptors and factor VIII related antigen was performed. Results: Histologic findings revealed cellular fascicles of spindle-shaped smooth muscle cells in a whorled arrangement. Mitotic figures were absent. Central degenerative changes and focal edema were observed. Between muscle fascicles, a significant amount of fat cells (20% of tumor volume) was visible. Leiomyocytes showed immunohistochemicaly positive reactions with actin, desmin, vimentin, and steroid hormone receptors. Based on these findings, the tumor was diagnosed as lipoleiomyoma. Conclusions: Origin of the tumor of smooth muscle cells of vessels located in the abdominal wall and development under influence of oral steroids seems most probable. HRT appears to promote the development of extrauterine leiomyomas in postmenopausal women.