A visual pitfall: persistent Müllerian duct syndrome (PMDS).

Persistent Müllerian Duct Syndrome (PMDS) is a rare disorder of the anti-mullerian hormone (AMH) synthesis or receptor, which due to the visual contrast of normal masculine external genitalia and female internal genitalia can raise confusion, sometimes during surgery for cryptorchidism or hernia inguinalis. For an acute and accurate analysis of such a situation a thorough knowledge of gonadal embryology is mandatory. The diagnosis is made on finding Müllerian structures in an individual with complete virilization without signs of hypocortisolism or exposition to maternal androgens during foetal life. Karyotyping and gonadal biopsy provide additional information to confirm the diagnosis. As the risk of malignant transformation is not clear, orchidopexy is advised in patients with cryptorchidism, with lifelong palpatory follow-up. In case of urologic symptoms, surgical removal of the Müllerian remnants can be considered, with careful attention for the vulnerable ductus deferens. Despite optimal treatment the prognosis regarding fertility remain uncertain.