Atypical polypoid adenomyoma--clinical histological and immunocytochemical findings

The clinico-pathological features of four examples of a distinctive benign uterine neoplasm are presented which has previously been titled atypical adenomyoma. The patients were all nulliparous and premenopausal. All presented with menstrual disturbances. No tumour has recurred after hysterectomy (follow-up between 10 years and 10 months). All tumours arose from the corpus, three were localised lower segment polyps, one a diffuse polypoid involvement of the endometrium. Histologically all of the tumours showed very similar appearances with closely packed, regular, tubular glands lined by low columnar epithelium, resembling most closely basal endometrial glands and surrounded by benign connective tissue which by simple tinctorial methods appeared to be largely smooth muscle. No heterologous components were seen. In two cases squamous metaplasia was extensive, in one microcalcification was present. The histological appearances favour a type of benign mixed Mullerian tumour but the appearances are not typical of Mullerian adenofibroma. Immunocytochemistry performed on 3 cases confirmed that the stroma was in large part smooth muscle, though much of the stroma stained only weakly with monoclonal antidesmin antibody.