Cystic retroperitoneal lymphangioma in infants and children.

Retroperitoneal lymphangiomas are uncommon benign tumors usually presenting in early life. They may cause significant pressure on adjacent structures, most often with superior and medial displacement of the kidney and medial deviation of the ureter. Relative radiolucency on total body opacification during excretory urography, and features of a cystic structure on ultrasonography and computed tomography should further suggest the possibility of a retroperitoneal lymphangioma. Vascular stretching and displacement without neovascularity on angiography and contrast entry into the cysts on lower extremity lymphography are additional features, but such procedures are usually unnecessary.