Case Presentation: PMDS is a rare form of XY-DSD in which Müllerian structures are present in phenotypically and karyotypically normal males. We report a case of a 6-year-old boy with left inguinal hernia repair, presented with abdominal pain, a reducible right inguinal hernia and hydrocele. Intraoperative findings revealed an atypical gonad and fallopian tube-like structure in the hernia. Genetic analysis identified compound heterozygous mutations in the AMHR2 gene, one known pathogenic and the other ‘tepid’ for pathogenicity.This case highlights the importance of considering disorders of sex development (DSDs) in paediatric patients with atypical hernia presentations.Introduction: PMDS is a rare autosomal recessive disorder in which individuals with a 46XY karyotype and normal male phenotype retain Müllerian structures(uterus, fallopian tubes)due to defects in either the anti-Müllerian hormone(AMH) or its receptor, AMHR2. The syndrome is typically discovered incidentally during surgical exploration for an inguinal hernia or undescended testes. Mutations in the AMH or AMHR2 genes disrupt the regression of the Mülleriaducts during fetal development despite otherwise normal male differentiation. Here, we report a rare case of PMDS discovered during elective hernia surgery in a healthy 6-year-old male with a confirmed AMHR2 gene mutation.Discussion: PMDS is a rare condition with fewer than 300 reported cases worldwide. It is typically discovered incidentally during procedures for inguinal hernia or cryptorchidism in children with an otherwise male phenotype and a 46XY karyotype. This patient’s presentation was classic in that Müllerian structures were unexpectedly discovered during routine hernia surgery. Although postoperative ultrasound did not detect Müllerian remnants, this is not uncommon, as imaging may lack sensitivity for intra-abdominal structures in pre-pubertal children. Mutations in AMHR2 impair the regression of Müllerian ducts during foetal development, even if AMH is produced in normal amounts. The risk of malignancy in undescended testes and Müllerian remnants, while low, is higher than in the general population and warrants consideration for regular follow-up or even prophylactic removal in some cases. Psychosocial support and endocrinological follow-up will be important as the patient approaches puberty, particularly in addressing fertility and hormonal development.
