An 18-year-old man was referred to this institution with complaints of general fatigue and facial edema.
Results of laboratory tests on admission indicated hypoproteinemia, hyperlipidemia, proteinuria, and hematuria. Ultrasonographic (US), computed tomographic (CT), and magnetic resonance imaging (MRI) studies
showed a polycystic tumor in the retroperitoneum. The tumor encircled the abdominal aorta and inferior vena cava and caused lateral deviation of the right ureter. No invasive tumor growth toward other retroperitoneal organs was observed, however. Lymphoscintigraphy led to a diagnoses of retroperitoneal cystic lymphangioma. Surgical treatment was thus mandatory.