Pediatric Aneurysmal Bone Cyst (ABC)

Pediatric Aneurysmal Bone Cyst (ABC)



An aneurysmal bone cyst (ABC) is a benign (noncancerous) blood-filled, fibrous growth.

Expanded overview

Typically occurring during the teenage years, aneurysmal bone cysts can grow on almost any bone, including the arms, legs, skull, spine and torso. The cyst will cause the bone to expand and deform. They can be removed with surgery, but may grow back.


There are two types of aneurysmal bone cysts:

  • Active – continues to grow, but is contained within the bone
  • Aggressive – continues to grow and spreads outside the bone to the soft, connective tissue like ligaments or tendons


The exact cause of aneurysmal bone cysts is unknown. Experts believe the cysts may grow due to a blood vessel abnormality in the bones, or because of a pre-existing condition like fibrous dysplasia (scar-like tissue forms instead of bone) or osteosarcoma (cancer that begins in bone cells).


Symptoms of aneurysmal bone cysts range from mild to severe and can include:

  • Fractures caused by pressure due to the cyst
  • Neurological problems (if the cyst is in the spine)
  • Pain
  • Swelling

Request Appointment