A newborn male infant was referred to our clinic because of anomalies of external genitalia. The infant was born at term after a normal pregnancy and delivery, and was appropriate for gestational age. A tumor mass covered with scrotum-like skin on its tip was noticed in the right side of perineum between the scrotum and anus. The raphe, which ran along the midline at the penis and the normal scrotum, circumscribed the right side of this structure. Both testes had descended into the scrotum. The condition was associated with incomplete penoscrotal transposition. There was no other urological anomaly including lower urinary tract. Histological findings of the tumor indicated perineal lipoma, and the scrotum-like portion was diagnosed as an accessory scrotum. Thirty-one report cases of the accessory scrotum including our own were reviewed and discussed.