EP1856 - LBA_ECE_1316 - Kallmann syndrome mimicking as Müllerian agenesis: a diagnostic challenge

Hypogonadotropic hypogonadism is a rare but important cause of primary amenorrhea. Kallmann syndrome, characterized by gonadotropin-releasing hormone deficiency and anosmia, may be misdiagnosed when prolonged estrogen deficiency results in non-visualization of reproductive organs. A 26-year-old woman with primary amenorrhea and absent pubertal development had previously been diagnosed with uterine and ovarian agenesis. Hormone replacement therapy had been recommended but not initiated. At presentation, she had poor breast development (Tanner stage II), normal external genitalia, and pubic hair consistent with Tanner stage III/IV. Her history revealed progressive hyposmia evolving into anosmia. Hormonal evaluation confirmed hypogonadotropic hypogonadism, and the karyotype was 46,XX. Initial imaging again failed to visualize the uterus and ovaries, raising suspicion of Müllerian agenesis. Pituitary MRI showed hypoplasia, and bone densitometry revealed osteopenia. Estrogen therapy was initiated. Follow-up ultrasound demonstrated uterine development with appropriate endometrial thickness and visualization of adnexal structures. After five months, transvaginal ultrasound confirmed a normal uterus with a trilaminar endometrium and both ovaries, excluding Mayer-Rokitansky-Küster-Hauser syndrome. MRI of the olfactory region showed hypoplastic olfactory structures, confirming Kallmann syndrome. Progesterone was added, resulting in regular withdrawal bleeding. This case highlights that prolonged estrogen deficiency can lead to misdiagnosis as Müllerian agenesis on imaging. Timely recognition and hormone therapy are essential for accurate diagnosis, restoration of reproductive anatomy, and preservation of bone and reproductive health.