Morular metaplasia misdiagnosed as adenoacanthoma in young women with polycystic ovarian disease.

Five cases of polycystic disease of the ovaries are presented; in four diagnosis of "adenoacanthoma" was made from an endometrial biopsy. The age range was 24-37. The fifth had been called "atypical glandular hyperplasia." In four of the five salpingoophorectomy and hysterectomy were performed, and the hysterectomy specimens showed no evidence of hyperplasia or carcinoma. Consultation review of the slides revealed "morular" metaplasia as well as tubal metaplasia. In one case, mucinous metaplasia was also present. Morule formation may distend glands and compress surrounding uninvolved endometrium, resulting in a pattern of back-to-back glands, that are, however, often lined by a single layer of columnar epithelium and should not be confused with back-to-back glands seen in adenomatous hyperplasia or adenocarcinoma. In both these conditions, the epithelium is stratified and shows nuclear atypism. Morules, especially when they coalesce, can be misconstrued as adenoacanthoma; however, the cells are uniform and bland in appearance.