Aneurysmal bone cyst

Aneurysmal bone cyst, abbreviated ABC, is a very common benign pathology of bone.

Aneurysmal bone cyst
Diagnosis in short
Aneurysmal bone cyst. H&E stain.
LM DDx	giant cell tumour of bone, telangiectatic osteosarcoma, other giant cell lesions
Site	bone
Prevalence	common
Prognosis	benign

Giant cell reparative granuloma (also known as solid aneurysmal bone cyst) is dealt with separately.

General

Features:

• Benign.
  • May grow rapidly.
• Osteolysis -> cystic space -> filled with blood.
• Relatively common; in children second only to osteosarcoma.

Gross/radiologic

Features:

• Air-fluid levels (radiology).
• Usually metaphysis of long bones, but uncommonly the femur.
• May have an "aggressive" appearance, i.e. erode bone.

Microscopic

Features:

• Bony trabeculae or osteoid tissue.
• Osteoclast giant cells.
  • Multi-nucleated giant-cells with round randomly arranged nuclei.
• Benign spindle cells (fibroblasts) - surround bone/adjacent to the giant cells - important.
• Blood +/- surrounded by giant cells.

DDx:

• Giant cell tumour of bone - the nuclei of the cells surrounding the giant cells are similar to those in the giant cells (round nuclei).
• Telangiectatic osteosarcoma.
• Other giant cell lesions.

Images

• 

  ABC - intermed. mag. (WC/Nephron)

• 

  ABC - high mag. (WC/Nephron)

• 

  ABC - very high mag. (WC/Nephron)

www:

• ABC - low mag. (webpathology.com).
• ABC - intermed. mag. (webpathology.com).
• ABC - high mag. (webpathology.com).

See also

• Bone.