Polyorchidism is an uncommon congenital anomaly, defined as the presence of more than 2-histologically proven-testes. Approximately 90 cases are reported in the literature. It is found predominantly on the left side. We report a right-sided polyorchidism found during orchidopexy in a 6-year-old boy. The supernumerary testis had its own tunica vaginalis, epididymis, and deferent duct, but shared the blood supply with the ipsilateral distal testis. The diagnosis was confirmed histologically. Because of the shortness of its vessels, the supernumerary testis could not undergo orchidopexy and was removed. We review the classification systems proposed for polyorchidism. Most are based on embryologic considerations, but none is capable of including all cases described in the literature. Thus, we present an anatomical system for a more comprehensive taxonomy of polyorchidism according to its reproductive function.
