Development of a hypoplastic uterus in a patient with testicular feminization syndrome 21 years after gonadectomy.

We describe a case of hypoplastic uterus, identified by transrectal ultrasonography and magnetic resonance imaging, which developed 21 years after gonadectomy for testicular feminization syndrome. Its likely origin was Müllerian-fusion remnant resulting from a deficiency in functional Müllerian inhibiting substance (MIS) and/or desensitization of the Müllerian tract to MIS, caused by diethylstilbestrol administration to the patient's mother during the sensitive period of the 6th and 9th gestational weeks of her pregnancy. This Müllerian-fusion remnant remained latent, due to insufficient estrogen stimulation both endogenously (until gonadectomy) and exogenously during hormone replacement therapy. Initial growth was possible induced in response to high doses of estrogen that the patient received over the last 3 years for the treatment of osteoporosis.