Müllerian adenosarcoma of the uterus:A clinicopathologic analysis of ten cases of a distinctive type of müllerian mixed tumor

The clinicopathologic features of 10 cases of a distinctive type of müllerian mixed tumor of the uterus are presented. With two exceptions, these tumors were discovered during the seventh to ninth decades. Most of them formed bulky polypoid growths that filled the endometrial cavity and produced vaginal bleeding. One tumor was an intramural mass. Low power microscopic examination revealed an admixture of benign appearing neoplastic glands and a sar-comatous stroma, creating a striking resemblance to the cystosarcoma phyllodes of the breast. The glands were lined by a variety of müllerian epithelial cell types, chiefly endometrial and squamous. The stromal element resembled endometrial stromal sarcoma in 9 cases, and embryonal rhabdomyosarcoma (sarcoma botryoides) in 1. No invasion of the myometrium, blood vessels, or lymphatics was observed, except in 1 case in which the tumor penetrated deeply into the myometrium. Five tumors recurred in the vagina or uterus, 3 on multiple occasions. Only 1 case, in which the stroma appeared highly malignant, was complicated by metastasis. Because of their generally low grade of malignancy, these tumors, for which we propose the term “müllerian adenosarcoma,” should be distinguished from the more aggressive classic forms of müllerian mixed tumor, the carcinosarcoma and the sarcoma of the endometrium.