Ruptured mesothelial cyst of the spleen causing acute peritonitis.

Congenital splenic cysts are rare (only 40% of all true cysts). A case report is presented of a young male adolescent patient with a ruptured mesothelial splenic cyst causing acute peritonitis. Abdominal ultrasound and CT-scan are very useful tools to obtain the preoperative diagnosis. Spleen saving resections, if possible, are preferred to splenectomy because of the risk of severe post-splenectomy sepsis.