Discharge of chyle through urinary excretion pathways. Urine acquires a unique milky, and whitish appearance, due to chyle mixed with urine. In the majority of cases, it is due to fistulas that link the urinary excretion pathways – from the pelvis of the kidney – with the retroperitoneal lymphatic and chyliferous system. It can be caused by traumas – of iatrogenic origin (such as, for example, following extensive para-aortoiliac lymphadenectomies in urologic surgery) -, or it can be correlated with complex dysplasia of intestinal and retroperitoneal chyliferous and lymphatic vessels.