Snap Shot A 33-year-old woman, gravida 4, para 4, complains of abnormal vaginal bleeding that occurs intermittently between her predictable menstrual cycles. A biopsy showed malignancy and an operation was performed. Introduction Malignant smooth muscle tumor arising from myometrium Bulky, irregularly shaped tumor with areas of necrosis and hemorrhage typically arising de novo (not a progression of a benign leiomyoma) More common in blacks Most commonly seen in postmenopausal women Presentation Symptoms abnormal uterine bleeding Physical exam may protrude from cervix Evaluation Usually diagnosed by ultrasound Confirm with tissue sample Prognosis Highly aggressive tumor with tendency to recur