Uterine Leiomyosarcoma Mimicking Benign Submucosal Leiomyoma

Uterine leiomyosarcoma is a rare, aggressive tumor of the smooth muscle with a typical intramural location. Patients present with abnormal uterine bleeding and an enlarged pelvic mass with clinical signs and symptoms that are virtually indistinguishable from benign leiomyoma. Sonographically, leiomyosarcoma presents as a large solitary tumor that closely resembles a benign leiomyoma that may be undergoing degenerative changes. Because of the infiltrative nature of leiomyosarcoma, invasion into the myometrium may be demonstrated. Leiomyosarcoma has a poor prognosis due to local pelvic recurrences and spread to distant sites. This case report demonstrates a fast-growing submucosal leiomyosarcoma with characteristic sonographic echo enhancement and infiltration into the myometrium.