Atypical polypoid adenomyomas of the endometrium.

Five unusual polypoid lesions of the endometrium which we term atypical polypoid adenomyomas are described; these growths occurred in premenopausal women. Each of the polyps was characterized by irregular atypical glands with squamous metaplasia and a cellular, smooth muscle mesenchyme, having a pattern to be distinguished from infiltrating adenocarcinoma or a malignant mixed müllerian tumor. Electron microscopy in one case confirmed the presence of a well-differentiated smooth muscle component. These lesions were focal and noninvasive. Two of the three patients who had hysterectomies has small residual lesions confined to the endometrium. Follow-up from 4 to 24 months showed no recurrence. One patient had a second D & C reported as normal; she subsequently became pregnant. The benign behavior of these unusual polyps suggests that atypical adenomyomas can be managed conservatively in the premenopausal woman without the necessity of a hysterectomy.