A gentleman of 45 years old presented with a painless swelling in the scrotum, of what seemed like a third testis. Clinically, it was a cystic swelling situated at the bottom of the scrotum, separately palpable from both the testis. Computed tomogram (CT) reported it as a cystic swelling arising from the perineum. Fine needle aspiration cytology (FNAC) and excisional biopsy were consistent with dermoid cyst. Its anatomy was accurately defined by CT of pelvis and perineum and guided us in accurate anatomical dissection. Such rare benign lesions should be considered in the differential diagnosis of painless scrotal masses.