Pathogenesis of aneurysmal bone cyst: Relationship between the aneurysmal bone cyst and fibrous dysplasia of bone

Aneurysmal bone cyst may arise in some patients with fibrous dysplasia of bone. The available material of aneurysmal bone cysts has been reviewed. In two cases, the coexistence of fibrous dysplasia and aneurysmal bone cyst was histologically confirmed. The secondary character of the aneurysmal bone cyst in relation to the fibrous dysplasia has been traced. We regard the aneurysmal bone cyst as a peculiar, non-neoplastic tumor secondary to a preexisting bone lesion. Among the superimposed pathologic conditions on which the aneurysmal bone cyst may take place is fibrous dysplasia of bone.