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Bone Cysts

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What Is a Bone Cyst?

Bone cysts are abnormal, liquid-filled pockets that form within your bones.

They mostly develop in long bones — such as the bones in the arms or legs — and often near a growth plate.

Types of bone cysts

There are two main types of bone cysts:

  • Unicameral
  • Aneurysmal

Unicameral bone cysts

A unicameral — or simple — cyst is the most common type of bone cyst. These cysts are benign, meaning that they are not cancerous and will not spread to other parts of the body.

Unicameral bone cysts occur more often in children and teens than in adults.

Aneurysmal bone cysts

Aneurysmal bone cysts also are benign, but they can be more serious than a unicameral cyst.

Bleeding inside the bone causes aneurysmal bone cysts. If the bleeding continues, it can lead to a large cyst that may deform the bone.

Bone cyst causes and risk factors

There are no known bone cyst risk factors since the medical community does not yet fully understand what causes them.

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Bone Cyst Symptoms and Diagnosis

Bone cyst symptoms

Because bone cysts typically don't cause pain or other symptoms, most people don't know they have a bone cyst. A small number of people might notice a slight bump on top of the affected bone.

Your doctor may find a bone cyst when:

  • Viewing x-rays for other health reasons.
  • Examining a broken bone.

Bone cyst diagnosis

Your doctor will begin with an x-ray of the area to see the exact size and location of the bone cyst.

If it's still hard to determine the size and location of the cyst, your doctor may order:

  • An MRI
  • A CT scan
  • A bone biopsy

These other tests can help your doctor find out what type of bone cyst you have.

Make an appointment for bone cyst care

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Learn more about tests for diagnosing bone cysts

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Bone Cyst Treatment and Surgery

The treatment of your bone cyst will depend on how severe it is. Many benign cysts will heal themselves over time.

Your doctor may want to monitor your cyst to see if it will require treatment.

Draining bone cysts

Doctors can drain some cysts by using a needle to remove the fluid and filling the bone with medicine to promote healing.

Bone cyst surgery

If your cyst has caused a broken bone, or your doctor thinks this could happen, you may need to have surgery.

Doctors surgically repair the broken bone with a bone graft or cement mixture to make your bone stronger.

Cysts often return after treatment. Your doctor may suggest routine x-rays to watch for signs of reoccurrence.

Make an appointment for bone cyst care

Request an appointment with a UPMC orthopaedic surgeon: