Aneurysmal bone cyst of the distal humerus


Aneurysmal bone cysts (ABCs) are a bone hamartoma (malformation) that consists of reactive hemorrhagic tissue that grows inside of a bone. The development and growth of an aneurysmal bone cyst is variable and can be extremely slow, even years, or very fast in the most aggressive forms that even reach large sizes. The metaphysis of long bones and vertebrae are the most common site but they can occur in any bone.