Fact-sheet: Aneurysmal bone cyst
Updated on 01/20/2026 at 6:02 PM
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Definition
Multiloculated intraosseous arteriovenous malformation: benign, expansile, osteolytic tumoral lesion with thin-walled loculations whose contents show hemorrhagic residua.
Etiologies:
- primary in most cases, sometimes with a history of trauma
- secondary to a preexisting tumor: giant cell tumor, osteoblastoma, chondroblastoma, hemangioma, telangiectatic angiosarcoma, solitary bone cyst, fibrous dysplasia, xanthoma, chondromyxoid fibroma, nonossifying fibroma, metastasis
Clinical features
Pain progressively increasing over 6 to 12 weeks
History of trauma
Location:
- Spine, with a slight predilection for the posterior elements, and possibly involving two contiguous vertebrae.
- Long bones: eccentric lesion of the metaphysis of the femur, tibia, humerus, fibula, pelvis.
Possible neurologic signs when the spine is involved
Radiography
Eccentric osteolytic lesion
Expansion with endosteal cortical resorption and cortical thinning
May show internal trabeculations
No periosteal reaction
Epiphysis is spared
CT
Same as radiographs, with:
- No cortical breach or soft tissue invasion
- Fluid-fluid levels
MRI
Multiple loculations of differing signal corresponding to hemorrhage of different ages, with fluid-fluid levels.
Intact hypointense periosteum
Heterogeneous enhancement
Vascular intervention
Angiography: peripheral hypervascularity, preoperative embolization.
Percutaneous sclerotherapy of spinal ABCs possible by injection of Fibrovein (Sodium Tetradecyl Sulphate Foam)
Nuclear medicine
Peripheral hyperfixation (inconstant)
Differential diagnosis
Bone lesions that may show fluid-fluid levels:
- Aneurysmal bone cyst
- Giant cell tumor (bone ends, metaphysis)
- Chondroblastoma (epiphysis)
- Osteoblastoma (posterior elements of the spine)
- Telangiectatic osteosarcoma (thick septa)
- Fibrous dysplasia (diaphysis, ground-glass)