Subperiosteal aneurysmal bone cyst with associated bone marrow oedema: An unusual appearance

Summary A case of a subperiosteal aneurysmal bone cyst with adjacent bone marrow oedema is presented. Aneurysmal bone cysts have been well documented in the published literature; however, relatively few have been observed in a subperiosteal location, and associated bone marrow oedema in the absence of a demonstrable pathological fracture is a rare finding. Aneursymal bone cyst should be considered in the differential diagnosis of subperiosteal bone lesions and may be associated with bone marrow oedema.