Aneurysmal bone cyst

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

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

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.