Derivatives of Mullerian ducts in a phenotypically male child with unilateral nonpalpable testis: a case report

Persistent Mullerian duct syndrome is a rare disorder of sex differentiation characterized by the presence of a uterus, fallopian tubes, and a vaginal outgrowth of the urogenital sinus in boys with a 46,XY karyotype. One variant of persistence of Mullerian duct derivatives in a child with male external genitalia is the mosaic chromosomal anomaly 45,X/46,XY, which clinically manifests as an inguinal hernia or cryptorchidism. This article presents a rare clinical case of failure of Mullerian duct regression in a phenotypically male child with a unilateral nonpalpable testis. A 17-month-old boy was admitted electively to the surgical department of Children’s City Clinical Hospital No. 9 in Yekaterinburg with left-sided nonpalpable testis syndrome. Diagnostic laparoscopy revealed a rudimentary uterus and left fallopian tube with a structure resembling an ovary. Postoperatively, the child underwent further evaluation (histopathological examination, hormonal status assessment, karyotyping, molecular genetic testing, and urethrocystoscopy). The clinical diagnosis was established as “disorder of sex development caused by chromosomal abnormality 45,X/46,XY, mixed gonadal dysgenesis.” In cases where persistent Mullerian ducts are detected intraoperatively, current practice is limited to biopsy of the abnormal gonad, urethrocystoscopy for visualization of the urogenital sinus, and, when possible, catheterization of the rudimentary uterus with a ureteral catheter to visualize its location in the pelvic cavity. For diagnostic confirmation, karyotype analysis, molecular genetic testing, hormonal profiling, and evaluation by a geneticist and endocrinologist are performed. The final decision regarding the child’s sex assignment, after all additional examinations, is made by a medical board in consultation with the parents.