Endometrial carcinoma is the most common form of genital malignancy diagnosed in women. Simple hyperplasia without atypia lies closest to normal proliferative endometrium. On the other end of the spectrum of preinvasive neoplasms is complex atypical hyperplasia (CAH), which from biologic, morphologic, and clinical perspectives resembles well differentiated endometrioid adenocarcinoma (WDA). Because CAH and WDA share so many important characteristics, tests for any one or a combination of these cannot definitively separate the two entities. Morphologically, CAH resembles WDA and, in many cases, substantial diagnostic sophistication is required to distinguish between them using current criteria. Two noteworthy articles based on the findings of the Gynecologic Oncology Group Protocol 167 have been published in this edition of Cancer and provide a glimpse of one group's approach to the diagnosis of CAH and its relevance.
See also pages 804–11 and 812–9.