Background: Patients with Turner's syndrome receiving unopposed estrogens for the induction of feminization have an increased risk of endometrial carcinoma. Only seven patients who were not treated with estrogen replacement therapy have been reported to have developed endometrial carcinoma at different age levels.
Case: A young girl with Turner's syndrome phenotype, spontaneous puberty, and karyotype 45,X0/47,XXX from peripheral blood, after irregular menstrual cycles of 9 years, at the age of 21, was diagnosed with a non-invasive well-differentiated endometrial carcinoma confined to a hyperplastic endometrial polyp. Analysis of the ovarian tissue by FISH confirmed mosaicism: 45,X0/46,XX/47,XXX.
Conclusion(s): The endogenous estrogen secretion from the ovaries might have caused malignancy in this case. Patients with Turner's syndrome with spontaneous menarche might carry a higher risk of endometrial carcinoma.