Copyright 2013 American Academy of Orthopaedic Surgeons
Osteoblastoma

Osteoblastoma is a benign (noncancerous) bone tumor. It is a rare tumor that often develops in the bones of the spine, as well as the legs, hands, and feet.

Adolescents and young adults are most often affected by osteoblastoma. The tumors typically appear between the ages of 10 and 30 years, and are twice as common in males as in females.

Because osteoblastomas destroy healthy bone and can grow to a large size, treatment always involves surgery to remove the tumor.

Description

Osteoblastoma is a slow-growing tumor that dissolves normal, healthy bone and makes a new type of abnormal bone material called osteoid. This osteoid bone material builds up around normal bone. Because the osteoid bone is weaker than normal bone, the area surrounding the tumor becomes more vulnerable to fracture. A bone weakened by an osteoblastoma can break with just a minor injury.

Although osteoblastoma is considered a benign tumor, there have been very rare cases in which an osteoblastoma has transformed into a malignant (cancerous) tumor.

Cause

The cause of osteoblastoma is not known.

Symptoms

Because osteoblastomas are slow to grow, the typical patient will have symptoms for about 2 years before the tumor is detected.

The most common symptoms of tumors found in the leg or arm bones are mild pain and swelling. However, many osteoblastomas develop in the spine. Tumors in the spine frequently cause back pain. In addition, tumors located in the spine can press on nerves. When this happens, patients usually develop neurological symptoms in the legs, such as numbness, weakness, or pain.

Osteoblastoma of the spine can also cause muscle spasm which can result in scoliosis, a sideways curve of the spine. Fortunately, this curve usually resolves after the osteoblastoma has been treated.

Legend: (Left) Normal lumbar (lower) spine anatomy. (Center) A magnetic resonance imaging scan of an osteoblastoma in the lower back that has caused a scoliosis curve. (Right) The same osteoblastoma shown in a computed tomography scan.
Doctor Examination

Medical History and Physical Examination

There are many aspects to the doctor's examination. Before a physical examination, your doctor will talk with you about your general health, as well as your symptoms in order to get a good history of the problem.

During the physical examination, your doctor will look for tenderness over the bone and check your range of motion in the painful area.

Tests

Your doctor will order imaging and tissue tests to diagnose osteoblastoma.

X-rays. These tests visualize dense structures like bone. Results from the x-rays will help your doctor determine whether more imaging scans are needed.

Other imaging scans. Your doctor may also request computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, or bone scans to help further define the tumor. These scans can provide more detail, especially of soft tissues. They can also provide cross-sectional images.

A CT scan or MRI scan will show your doctor more precisely where the tumor is located and what its specific characteristics are.

Biopsy. A biopsy is often necessary to confirm an osteoblastoma diagnosis. In a biopsy, a tissue sample of the tumor is taken and examined under a microscope. Your doctor may give you a local anesthetic to numb the area and take a sample using a needle. Biopsies can also be performed as a small operation.

(Left) An x-ray of an osteoblastoma on a patient's ring finger. (Right) An MRI scan of the same osteoblastoma shows the tumor mass in greater detail.

Osteoblastoma and Osteoid Osteoma

Osteoblastoma is closely associated with another benign bone tumor: osteoid osteoma. Both tumors form abnormal osteoid bone material, and both occur more frequently in younger people, particularly males.

Osteoid osteomas are smaller than osteoblastomas, and they do not grow. Pain from osteoid osteoma often worsens at night, but can be relieved with non-steroidal anti-inflammatory medications (NSAIDs), like ibuprofen. Osteoblastomas do not typically cause night pain, and they do not respond as well to NSAIDs.

In addition, osteoblastoma requires surgery to remove the growing tumor. Osteoid osteoma does not require surgery if the associated pain can be managed with NSAID treatment.

Treatment

Treatment for osteoblastoma requires surgery. The tumor must be removed without damaging the surrounding structures.

Marginal Resection

Your doctor may remove the section of bone where the tumor is located.

Curettage and Bone Grafting

In this procedure, the tumor is scraped out of the bone. In some cases, the hole is filled with a bone graft — this is bone taken from a donor (allograft) or from another bone in your body (autograft). Your doctor may also use a bone cement mixture to fill the hole.

Spinal Fusion

Treatment for tumors in the arms and legs is usually straightforward, however, there may be more challenges when the tumor is located in the spine.

After a tumor is removed from the spine, a spinal fusion may be needed to support the area. A spinal fusion is essentially a "welding" process. The basic idea is to realign and fuse together the weakened spinal bones so that they heal into a single, solid bone.

Radiation Therapy and Chemotherapy

These treatment options are not recommended for osteoblastoma except in rare circumstances. For example, if the tumor is located in the spine and the surgeon cannot safely remove the entire tumor, then radiation therapy is sometimes recommended.

Recovery

How long it will take to return to daily activities will vary depending on where the tumor was located and which procedure you had to remove it. Your doctor will provide you with specific instructions to guide your rehabilitation.

Osteoblastoma returns in approximately 10 to 20% of patients. The likelihood of the tumor recurring is related to how well it can be completely removed without causing damage to normal structures. Should the tumor recur, it can be treated using the same methods. Your doctor will talk to you about all the options.

Last reviewed: June 2013
AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS "Find an Orthopaedist" program on this website.
Copyright 2013 American Academy of Orthopaedic Surgeons
Related Links
Osteoid Osteoma (http://orthoinfo.aaos.org/topic.cfm?topic=A00507)
Bone Tumor (http://orthoinfo.aaos.org/topic.cfm?topic=A00074)
Spinal Fusion (http://orthoinfo.aaos.org/topic.cfm?topic=A00348)
OrthoInfo
The American Academy of Orthopaedic Surgeons
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Phone: 847.823.7186
Email: orthoinfo@aaos.org

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