Retroperitoneal multiple lymphangioma with differential cyst contents causing hydronephrosis and biliary dilatation

We report a 40-year-old woman with retroperitoneal multiple cystic lymphang ioma. Multiple cystic lesions were found on both sides of the aorta in the retroperitoneal and right pelvic spaces. These thin-walled cysts gradually increased in size leading to left hydronephrosis and dilatation of the comm on bile duct with cholecystitis, requiring resection. Analysis of cystic co ntents revealed differences between the cysts. The right cyst contained hig h concentrations of amylase, 3429 U/L, while the left cyst contained high c oncentrations of triglyceride, 470mg/dL. No reports of patients with idiopa thic retroperitoneal cystic lymphangioma have described differences in cyst ic contents. Differences in cystic contents according to tumor location str ongly suggest that the cause of retroperitoneal lymphangioma is a developme ntal malformation in which lymphangiectasia follows the failure of developi ng lymphatic tissue to establish normal communication with the remainder of the lymphatic system.