We report a 43 years old male admitted to the hospital for progressive lumbar pain, lasting 20 years, that caused severe disability. On admission the patient had a serum phosphate of 2 mg/dl, an urine phosphate excretion over 300 mg/dl and serum alkaline phosphatases over 750 U/L. Serum intact parathormone was normal and tubular maximum phosphorus/glomerular filtration was 0.7 mg/dl. Bone scintigraphy showed an increased radionuclide uptake in condro-costal joints. Bone densitometry showed femoral osteoporosis. A violet colored mass was detected in a great toe. It was removed and the pathological diagnosis was a composite hemangioendothelioma. After tumor excision, serum phosphate levels returned to normal values and symptoms disappeared within 15 days (Rev Méd Chile 2003; 131: 909-14)