Summary

A 28-year-old offshore worker attended accident and emergency department with a tender benign-feeling lump inferior to the left testis. He was previously investigated abroad with an ultrasound scan showing a homogenous mass posterior to the left testis. Subsequent CT was unremarkable. As there was no clinical suspicion of malignancy, a scrotal exploration was performed. During scrotal exploration, the left testicular mass appeared to be a supernumerary testis, which shared the same tunica albuginea. Histology has confirmed the diagnosis. Polyorchidism is an extremely rare congenital anomaly, and can be associated with hydrocele, testicular torsion or rarely malignancy. Leung has classified polyorchidism in four types. This case has been described as type 2; the supernumerary testis shares the epididymis and the vas deferens of the other testis. Treatment can either be conservative or surgical excision. However, if the supernumerary testis is asymptomatic, with negative tumour markers and radiological findings, surgery can be avoided.