'Testicular masquerade': a case report of testicular malignancy with persistent Müllerian duct syndrome and transverse testicular ectopia.

Persistent Müllerian duct syndrome (PMDS) is a rare sexual development disorder. It is even more rarely associated with transverse testicular ectopia (TTE), a rare form of testicular ectopia, in which both testes descend through a single inguinal canal and are present in the same hemiscrotum. PMDS with TTE is associated with 18%-33% malignant transformation. Here we report the case of a 48-year-old man who presented with a large right inguinoscrotal swelling and on evaluation was found to have a large right testicular mass with complete right inguinal hernia, undescended left testis and a central abdominal mass. On evaluation with contrast-enhanced computed tomography abdomen and pelvis and image-guided biopsy he was diagnosed with mixed germ cell tumour of the right testis (predominantly a seminoma) with a retroperitoneal nodal mass and absent left testis, for which he received chemotherapy. Post-chemotherapy he underwent surgery and was diagnosed intraoperatively with PMDS along with TTE and testicular malignancy arising from the ectopic left testis. Postoperative recovery and follow-up were uneventful. Most cases of PMDS are diagnosed early in life. They present clinically with unilateral or bilateral undescended testis with inguinal hernia. In adults, PMDS is usually associated with male infertility. However, TTE is associated with an increased risk of testicular tumours if undiagnosed until adulthood. In adults PMDS with TTE is usually an intraoperative finding and is commonly associated with malignancy in the ectopic/undescended testis.