Cause
- Intraosseous accumulation of variable-sized, blood filled spaces surrounded by cellular fibrous connective tissue and reactive bone.
- Theorized that traumatic event, vascular malformation, or neoplasm may disrupt normal osseous hemodynamics and leads to an enlarging, hemorrhagic extravasation.
Incidence
- Gnathic lesions mainly affect young patients (mean age 20 years).
- No sex predilection
Location
- Aneurysmal bone cysts are located most commonly in the shaft of a long bone or in the vertebral column in patients younger than age 30.
- Gnathic aneurysmal bone cysts are uncommon, with approximately 2% reported from the jaws.
- Mandibular predominance with vast majority in the posterior jaw.
Clinical Presentation
- Rapidly enlarging swelling.
- Pain, paresthesia, crepitus are rarely seen.
- Malocclusion, mobility, migration, or resorption of involved teeth may be present.
Radiographic Features
- Unilocular or multilocular radiolucency, often with marked cortical expansion and thinning.
- Border may be well defined or diffuse.
Compare to:
Histopathology
- Blood-filled spaces that lack an endothelial or epithelial lining. Surrounding cellular fibroblastic tissue contains multinucleated giant cells, osteoid and woven bone (similar to CGCG)
Treatment
- Enucleation and curettage
- At time of surgery, intact periosteum and a thin shell of bone is typically found covering the lesion. Cortical perforation may occur, but spread into adjacent soft tissue has not been noted.
- Reccurence ranges from 8% to 60%, likely secondary to incomplete removal of lesion.
- En bloc resection reserved for extensive or recurrent lesions.
