Lymphangiomas are rare benign cystic tumors caused by uncontrolled lymphatic growth. Most lymphangiomas arise in the axilla or neck. In approximately 1% of cases, lymphangiomas develop in the retroperitoneal space, characterized as a retroperitoneal cystic lymphangioma.

These tumors can be asymptomatic, but often, due to their size and location, patients will present with a palpable abdominal mass, bowel obstruction, abdominal pain, anorexia, weight loss, ascites, or obstructive nephropathy from ureter compression. Asymptomatic cases can be found incidentally during surgery or autopsy.

The diagnosis of a cystic lymphangioma typically requires pathology, as the appearance of a complex cyst on cross-sectional imaging is not specific to these types of tumors.