Intracortical and subperiosteal aneurysmal bone cysts: a report of three cases.

Aneurysmal bone cyst of the long bones in a purely intracortical or subperiosteal location is unusual. Three such cases are reported, and the radiographic and pathologic differential diagnoses are discussed. Those subperiosteal or intracortical aneurysmal bone cysts with radiographic features similar to the intramedullary variety should suggest the same diagnosis. However, the radiographic features may be less specific, so that a diagnosis of aneurysmal bone cyst must be entertained when considering a subperiosteal or intracortical lytic lesion.