What is an Aneurysmal bone cyst?
This is a fibrous blood-filled bone lesion and can potentially destroy bone tissue. It can also grow rapidly and is usually benign. They are called aneurysmal because they resemble an aneurysm when they are viewed on an x-ray. It is a rare type of bone cysts and of all bone tumors (cyst) they account for one to six percent. An aneurysmal bone cyst can grow in any bone in your body but the most likely location is the bones of your knee, your skull, your spinal vertebrae, and your limbs. They are more commonly found in teenagers with approximately eighty-six percent of them developing in those younger than twenty years of age. They can develop in any age group but on average most are between the ages of thirteen and seventeen. Females are more likely to have these than males.
Many times an aneurysmal bone cyst does not cause symptoms because they are so small but if they do, what they will be depends on where these aneurysmal bone cysts are located. If there are symptoms they will be at the site of the cyst and can include:
- Bone deformity
- Bone pain
- Feeling of warmth in the area that is affected
- Joint stiffness, reduced range of motion, or weakness if it located near a joint
- Neurological symptoms if it grows in your spinal bones
- Weaken bone tissue that can lead to an increased risk of a fracture if the cyst grows rapidly
It is unknown what the exact underlying cause of aneurysmal bone cysts are. Some will develop in areas:
When an aneurysmal bone cyst is so small it does not cause any symptoms they are usually only discovered when they have x-rays for an unrelated cause.
If it is necessary to treat an aneurysmal bone cyst it will usually include surgery to remove the cyst and to repair the bone that is affected but surgery is not always required. The treatment most commonly used is cottage of the aneurysmal bone cyst followed by bone grafting. This procedure involves opening the cyst and scraping out the contents using a scooped instrument called a curette. Once it has been cleaned out it will be filled in with a bone graft or other synthetic filler. This procedure is done under general anesthesia and generally will require an overnight stay in the hospital but may be done as an outpatient surgery. It takes approximately sixty minutes to do the surgery. Unfortunately, this procedure has the highest potential for recurrence. The reason is because of the difficulty in removing all the contents of the aneurysmal bone cyst.
Sometimes after curettage, they will use cryotherapy to help reduce the possibility of recurrence. This is a form of cold therapy but this therapy can cause nerve damage or bone fractures so it is not a common form of treatment. If the cyst is located in a bone that is non-weight bearing it can be removed via complete excision instead of curettage of the interior of the cyst. If it is possible to completely remove the aneurysmal bone cyst it will reduce the risk of recurrence.
If the aneurysmal bone cyst is growing very slowly or not growing at all it is not treated. In these cases you will be monitored for any signs that the rate of the growth of the cyst is increasing. Monitoring can include regular MRI or CT scans to evaluate the size of the cyst.
After having the surgery you will follow up with your orthopedic surgeon in seven to fourteen days, then again at three months and six months. You will also be check once a year to see if the cysts are recurring.