[Radiologic findings in Gorham-Stout syndrome].

Gorham-Stout syndrome, also called "disappearing bone disease" or idiopathic massive osteolysis, is a rare disease of unknown etiology and pathogenesis. It is characterized by rapidly progressive localized massive osteolysis associated to a proliferation of vascular structures of benign origin in which the absence of new bone formation is representative. We present two cases (a six-year-old boy with affected right ulna, and a 15-year-old girl with right rib affection associated to chylothorax) of this disease with the characteristic clinical, histological, and imaging findings.