Endometrioma of uterine serosa in a woman with mosaic Turner's syndrome receiving hormone replacement therapy: case report.

Endometriosis in Turner's syndrome patients has only been reported in five isolated cases. We present here an endometrioma on the uterine serosa and pelvic endometriosis arising in a mosaic Turner's patient receiving hormone replacement therapy (HRT). The 24 year old patient with mosaic Turner's syndrome [45,X; 46,X pseudo dicentric Y (q11.23)], on cyclic HRT after laparoscopic gonadectomy 5 years previously, was found to have an adnexal mass on routine examination. Given her history, due to the fear of a malignant process arising from a potential gonadal remnant, she underwent a laparoscopy and was found to have a 5 cm serosal endometrioma arising on a stalk from the uterine fundal surface as well as pelvic endometriosis. De-novo endometrioma and endometriosis occurred in a mosaic Turner's patient after gonadectomy on cyclic HRT. The presentation was also unusual with a pedunculated endometrioma arising from the uterine serosa. Due to the fact that the patient did have cyclic menstrual flow, her endometriosis may have arisen from retrograde menstruation or coelomic metaplasia induced by exogenous hormones.