A case of chyluria with nephrotic-range proteinuria caused by lymphatic malformation, leading to a diagnosis of Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a rare syndrome, which is clinically diagnosed by the presence of unilateral limb hypertrophy with vascular malformation including cutaneous capillaries, veins and lymphatic vessels. Most cases typically exhibit cutaneous manifestations such as port-wine stains and limb hypertrophy from infancy, but cases with mild manifestations may remain undiagnosed. We here report a case of KTS who was diagnosed by chance chyluria. A 15-year-old girl who exhibited hematochyluria with nephrotic-range proteinuria was referred to our hospital. She had been diagnosed as idiopathic scoliosis accompanied by left lower limb hypertrophy in the past. She noticed her milky urine for the first time two months before. Immediately thereafter, she noticed edema of her left leg. Hematochyluria with nephrotic-range proteinuria was found by our initial urine examination. Magnetic resonance imaging suggested venous or lymphatic malformation along the left common iliac vein at the retroperitoneal side. Lymphoscintigraphy showed congestion of radioisotope around backside of the pancreas to the left renal hilus, suggesting an existence of lymphostasis. Based on the findings, we diagnosed the patient as KTS. After admission, hematochyluria and proteinuria were decreased and became insignificant by three days with bed rest. Her left leg edema was reduced. After taking a guidance to avoid intensive exercise, she was discharged in two weeks. Because the present case exhibited mild manifestations, diagnosis was made by urine abnormalities for the first time. The case suggests that we should be aware of the presence of undiagnosed patients of KTS due to relatively mild manifestations.