Simple bone cyst: etiology, classification, pathology, and treatment modalities.

Simple bone cyst (SBC) is an enigma to the radiologist, pathologist and the orthopaedic surgeon. The etiology of this asymptomatic lesion that frequently causes pathological fracture is still unknown. It is probably self limited in nature, seen in children but rare among adults. The biological behavior is unpredictable as is the clinical course in various anatomical sites. This reflects on the high recurrence rate that has been associated with various treatment modalities. The clinical, radiological and biological features are discussed together with comparative review of treatment options from resection, curettage, and bone grafting to steroid injection and the latest experience of the use of percutaneous autologous marrow grafting in SBC.