Retroperitoneal cystic lymphangiomas are uncommon tumors usually found incidentally at surgery, autopsy, orlymphography. When clinically significant, they usually present early in life as a palpable abdominal mass. Wediscribe an unusual case of a six-years old boy who was operated for a cystic lymphangioma of the right axilla atthe age of five months, and, six years later, was found to have a retroperitoneal cystic lymphangioma accompainedwith motor weakness of the lower extremities.