Abstract
A 22 year-old phenotypic female with a 45,x/46,x, r(x) mosaic complement had anovulatory cycles, histologically normal ovaries, and atypical endometrial hyperplasia which, when clinically followed by repeated biopsies, was found to progress to locally invasive endometrial carcinoma. This was successfully managed by the induction of ovulation with Clomid, which resulted in conversion of the endometrium to a normal secretory pattern for two subsequent years.