Persistent Müllerian duct syndrome

Persistent Müllerian duct syndrome (PMDS), also known as hernia uteri inguinalis or persistent oviduct syndrome, is a rare disorder of sex development affecting 46,XY males (genetically male individuals). In typical male fetal development, anti-Müllerian hormone (AMH) produced by the testes causes the Müllerian ducts to regress. In PMDS, either AMH is not produced properly or the receptor for AMH does not function correctly, resulting in the persistence of Müllerian duct derivatives — specifically the uterus, fallopian tubes, and the upper portion of the vagina — in an otherwise phenotypically male individual. External genitalia are typically male in appearance. The condition is most commonly discovered during surgery for inguinal hernia or cryptorchidism (undescended testes), which are the hallmark clinical presentations. One or both testes may be undescended, and the uterus and fallopian tubes may be found within an inguinal hernia sac (a presentation historically called "hernia uteri inguinalis") or in the pelvis. A characteristic form called transverse testicular ectopia, where both testes are found on the same side, may also occur. Affected individuals are at increased risk for infertility due to impaired spermatogenesis, and there is a potential increased risk of gonadal malignancy, particularly if the testes remain undescended. PMDS is caused by pathogenic variants in either the AMH gene (encoding anti-Müllerian hormone, PMDS type I) or the AMHR2 gene (encoding the AMH type II receptor, PMDS type II). Treatment is primarily surgical and involves orchidopexy (surgical placement of the testes into the scrotum) to preserve fertility potential and reduce malignancy risk. The Müllerian remnants are often left in place if their removal risks damaging the vas deferens or blood supply to the testes, though careful dissection and removal may be attempted. Hormone replacement is generally not required as testosterone production is typically normal. Long-term follow-up is recommended to monitor for gonadal tumors.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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