[Retrorectal cystic hamartoma].

The pathogenesis of retrorectal cystic hamartomas in the presacrococcygeal space, while known to be related to embryological remnants of the caudal region, is controversial. These lesions are rarely found in children; in the early stages of their development they may be symptomless. Diagnosis is usually made when the tumor is large enough to cause pain or intestinal obstruction, or when it becomes infected. A 2-month-old girl with a retrorectal cystic hamartoma initially treated as a perianal abscess is presented.