Perforation of a mesenteric cyst is a very rare complication of a very unus
ual lesion. Acute presentation is the rule in half of all affected children
. Ultrasonography and computed tomography are the hest preoperative diagnos
tic tools. The treatment of choice is an urgent laparotomy and complete cys
t removal. Results are good in cases that are operated on in a timely manne
r.