Abstract: Gorham-Stout syndrome is a rare disease characterized by osteolysis, in which idiopathic intraosseous angiomatous proliferation leads to progressive resorption of bone. Chylothorax can be associated with Gorham-Stout syndrome in some cases, but chyloperitoneum is seldom seen. This paper reports a case of Gorham-stout syndrome that was admitted to the gastroenterology department because of ascites. The way of chyloperitoneum formation was confirmed by lymphangiography.