label: Simple Bone Cyst
label_lc: simple bone cyst
description: "A usually unilocular, intramedullary cystic cavity in the bone.  It is lined by fibrous tissue and is filled with serous or serosanguineous fluid.  It can arise from any bone.  The most frequent sites are proximal humerus, proximal femur, and proximal tibia.  In most cases the lesion is asymptomatic and is usually detected after a pathologic fracture or during radiologic examination for unrelated reasons.  Recurrences have been reported in a minority of cases."