An unusual extrauterine (pelvic) variant of adenosarcoma is presented. A benign-appearing epithelium resembling fallopian tube epithelium is integrally mixed with malignant stroma that in all areas sampled is low-grade leiomyosarcoma. The tumor has behaved as a low-grade malignancy with four local recurrences over a 16-year period. Extrauterine adenosarcomas have rarely been reported in the literature; and one in which the stromal component is histologically all of smooth muscle differentiation is more unusual.