Polyorchidism.

Transverse division of the embryologic genital ridge explains the various forms of polyorchidism that have been reported. Most patients with supernumerary testes are asymptomatic and have painless groin or testicular masses. The majority have triorchidism, and the supernumerary testis is most frequently on the left side. The most common associated anomalies are inguinal hernia and maldescent of the testis. Testicular biopsy is essential for diagnosis.