Giant purulent mesenteric cyst.

Infected intra-abdominal cystic lymphangiomas are very rare. We report a case of a purulent mesenteric cyst, histologically a cystic lymphangioma, w which developed in a 1-year-old girl who presented with marked abdominal distension and high fever. Magnetic resonance imaging revealed that the huge cystic lesion occupied the entire peritoneal cavity. It originated from the mesocolon. It was removed completely, and contained sticky pus at the base where the right fallopian tube penetrated it, which indicated the focus of infection. This may be the first report of a purulent mesenteric cyst in which the route of infection was suspected.