Aneurysmal Bone Cyst

Description: Aneurysmal bone cyst (ABC) is a solitary, expansile and erosive lesion of bone. It is found most commonly during the second decade and the ratio of female to male is 2:1. ABC's can be found in any bone in the body. The most common location is the metaphysis of the lower extremity long bones, more so than the upper extremity. The vertebral bodies or arches of the spine also may be involved.Approximately one-half of lesions in flat bones occur in the pelvis. One theory of the etiology of primary ABCs is that these lesions are secondary to increased venous pressure that leads to hemorrhage which causes osteolysis. This osteolysis can in turn promote more hemorrhage causing amplification of the cyst. Bonetumor.org