Anterior sacral meningocele presenting as abdominal mass.

Anterior sacral meningocele is a rare entity. It arises from a congenital defect of the sacrum and the coccyx through which herniation of the caudal portion of the meninges and their contents occurs, forming a cyst-like structure. The cystic mass, which lies between the rectum and sacrum, produces a variety of symptoms depending on its size and contents and constitutes a diagnostic problem. A case of anterior sacral meningocele is presented, including the physical signs, differential diagnosis, and the dangers of aspiration or surgical intervention.