Background: Disappearing bone disease -Gorham Stout disease a unparallel case of Unknown Origin . Medical condition of Bones, which does not have any specic etiology. An extremely rare disorder, which causes the proliferation of endothelial channels and can lead to results and disappearance of bone. Here sudden bone osseous matrix is destroyed and also lymphatic vascular structures up proliferated and further leads to excessive regional osteolysis.With a variating clinical presentation and very often is diagnosed as benign disease which further spreads to an unclear prognosis.Mainly diagnosed by single and various combinations like clinical features, histological ndings and radiological ndings. Many therapeutic options have managed to provide certain efcacy, but most effective therapeutic option is still controversial without a certain standard treatment protocol Case presentation:A case of disappearing bone disease affecting the proximal femur, pelvis, sacrum in a 45 year old male has been described here. Clinical features of the disease are pain , swelling of the affected region, functional impairment. In this case the diagnosis was made after the pathological fracture of femur. Based on radiological and clinical ndings. Considering stabilisation as an important aspect internal xation that was done followed by Bisphosphonates used for progession control and is now being currently followed up with no cessation of disease. But internal xation has prevented complete severe disability. Conclusion:Hereby given that conrmed ethiopathology of disappearing bone disease is not completely veried and further study is still needed to effectively treat and provide intervention. But the need for every physician to know of it's presence, promptly direct a patient towards the right direction and we are hence reporting this for it's rarity.