Congenital perineal lipoma: an unusual presentation.

dichorionic triamniotic pregnancy. A caesarean section was performed at 34 weeks of gestation. The Apgar score was 9/10, weight 2425 g and physical examination revealed a congenital malformation in the perianal region with 13.8 mm of greater axis, spherical pedunculated and soft, with a cylindrical 5 mm form attached, similar to an accessory penis and scrotum (figure 1). The neonate underwent an ultrasound displaying normal structures with an external malformation consistent with an accessory testicle, while MRI showed a complex structure, compatible with type I sacrococcygeal teratoma (figure 2). At 6 months of age (figure 3), the mass was locally excised, without complications. Postoperative histological examination however, revealed a subcutaneous lipoma. Isolated congenital perineal lipomas are rare lesions that can lead to a misdiagnosis of an accessory scrotum in men, in particular because these two conditions can be associated in over 80% of cases. 2 The differential diagnosis is mainly an accessory scrotum, sacrococcygeal teratoma, fetus in fetu, haemangioma, haemartoma or lipoblastoma. A complete evaluation of the urogenital and anorectal tract is recommended, taking into account related anomalies described such as renal agenesis, anorectal malformations, scrotum and penile anomalies. These isolated lesions are usually benign and the standard treatment is local excision.