Gorham Stout disease is a very rare monostotic or polyostotic osteolysis and physiopathology of the osteolysis is not yet fully understood. Three new cases are reported with their evolution and treatment. Among these 3 cases, two are very rare cases of polyostotic involvement. One patient finally deceased from respiratory complications despite limb amputation. The two others are alive. Both needed final reconstruction with massive bone allograft for one and with a prosthesis for the other. Monostotic osteolysis is the most frequent presentation of Gorham Stout disease and extensive polyostotic osteolysis is very rare. Treatment methods vary from one clinic to another, from drug treatment to surgical treatment with or without radiotherapy. Sometimes, as a last solution, an amputation of the affected limb is performed. The prognosis depends on the affected region and the reponse to various treatments. Chylothorax seems to be a factor of poor prognosis.