Benign and low grade variants of mixed Müllerian tumour of the uterus

The clinico-pathological features of 11 examples of a rare group of uterine neoplasms composed of both epithelial and stromal components are reported. The patients complained of abnormal vaginal bleeding or discharge. Two of the tumours arose in the cervix, seven in the endometrium and two from both, forming large polypoid masses projecting from the cervix and/or filling the uterine cavity. Microscopically, the epithelial elements ranged from benign to adenocarcinoma. A similar range of stromal elements was also seen, varying from entirely bland to low grade to high grade sarcoma. The variable histology of the tumours is reflected in their biologic behaviour. Of the three tumours with the highest histological grade of malignancy, one recurred and killed the patient. One tumour, in which both components were regarded histologically as benign, recurred twice before hysterectomy. Our findings lend support to the concept that these tumours are variants of mixed Müllerian tumour. We advocate the acceptance of the latter term so that all grades of this tumour can be accommodated under one designation.