Müllerian adenosarcoma of the uterine body: a report of nine cases.

Nine cases of Mullerian adenosarcoma of the uterine body, first defined in 1974 by Clement & Scully, are described. The tumour usually occurs in elderly women and appears macroscopically as a polypoid mass filling the uterine cavity. Histologically these neoplasms are characterized by having a benign epithelial component set in a sarcomatous stroma. The epithelial element consists of tubular glands, cystically dilated glands and a surface epithelium. The glandular and surface epithelium usually resembles that of proliferative endometrium but may be of mucinous type and can undergo squamous metaplasia. Occasional mitotic figures, multilayering and intraluminal tufting are seen in the actively growing but benign glands which are considered to be an integral component of the tumour. The sarcomatous stroma contains spindle cells, round cells and, less frequently, multinucleated giant cells and rhabdomyoblasts. The Mullerian adenosarcoma represents a relatively benign variant of the mixed mesenchymal sarcoma of the uterus and is probably more common than is generally realized. Myometrial invasion is rarely deep and the majority of patients with this neoplasm survive. Vaginal recurrence occurs only in a minority of patients and distant metastasis is exceptional.