Eccentric simple bone cysts of the femoral neck in adults

The purpose of this communication is to describe atypical simple bone cysts of the femoral neck seen in adult patients. Two patients, aged 56 and 49, having cystic lesions which did not conform to a typical simple bone cyst, are reported. Common features including eccentric location, and thick lining tissue and sclerotic margin are not those of typical simple bone cysts seen in children. Local mechanical characteristics might be related to the atypical presentations.