Pediatric benign bone tumors and cysts

What are benign bone tumors and cysts?

Noncancerous bone tumors happen when bone cells grow out of control and form growths. Most pediatric bone tumors are benign and don’t spread to other parts of the body. They may cause pain, weaken the bone and increase the risk of a fracture (broken bone).

A bone cyst is a fluid-filled sac inside a bone. Most bone cysts develop in the long bones of the arms or legs. Bone cysts usually don’t cause symptoms and can go away on their own. Sometimes, they can weaken the bone and increase the risk of a fracture.

What are the different types of benign bone tumors and cysts?

Certain benign bone tumor and bone cyst types occur more commonly in children. These types include fibrous lesions, cartilage-forming tumors, bone-forming tumors and bone cysts.

Fibrous lesions

Nonossifying fibromas (NOFs) are the most common type of benign bone tumor in children. They typically grow in the lower thigh bone (femur) or the ends of the shinbone (tibia). NOFs usually don’t cause symptoms, and they may not need treatment because they often go away on their own.

Cartilage-forming tumors

Osteochondromas usually grow on the surface of a bone near the growth plates. Growth plates are areas of developing cartilage at the ends of the bones, where growth happens, and they harden into solid bone when children are full-grown. Osteochondromas usually develop as one tumor but may occur as several tumors.

Bone-forming tumors

Osteoblastomas are slow-growing tumors that develop in the bones of the spine, legs, hands and feet. Osteoblastomas can destroy healthy bone tissue and grow large, so treatment always involves surgery to remove the tumor.

Bone cysts

Two types of bone cysts commonly occur in children:

• Aneurysmal bone cysts. This type of cyst forms as a group of blood-filled sacs that usually grow near the inside edges of the long bones, but they can occur in almost any bone. Aneurysmal bone cysts tend to grow slowly, but they can deform the bone and cause fractures.

• Unicameral bone cysts. These cysts typically form as a single, fluid-filled sac near the growth plates in the long bones of the arms or legs. Also called simple bone cysts, this type can cause the surrounding bone tissue to thin, which can lead to a fracture.

What are the signs and symptoms of benign bone tumors and cysts?

• Pain, a dull ache or tenderness, especially with activity

• Numbness or tingling

• Swelling

• Painless bump if near a joint

Benign bone tumors and cysts often don’t cause symptoms, but these are the symptoms that may occur. In many cases, doctors discover the growth in X-rays or other images taken for another reason (called an incidental finding).

How are benign bone tumors and cysts diagnosed?

At Children’s Health, our experienced doctors start with a physical exam. During this time, we ask you about your child’s symptoms and their personal and family medical history, such as a history of any tumor or cancer. If your child has had previous tests or treatments, it would be helpful to bring those records.

We may also order imaging scans to confirm a diagnosis and rule out cancer and other conditions. These diagnostic imaging and other tests may include:

• X-rays. This imaging uses high-energy radiation to produce detailed images of bones to show growths.

• CT (computed tomography) scan. CT scans use a computer to combine X-rays to create cross-sectional images of bones.

• MRI (magnetic resonance imaging). This imaging uses powerful magnetic fields and radio waves to produce pictures of bones and soft tissue, such as cartilage.

• Low-radiation, full-body scans. We offer EOS imaging to take full-body X-rays with lower doses of radiation. The machine scans your child standing up, which allows us to see their natural, weight-bearing posture. This imaging also shows bones, joints and other tissues from multiple angles for greater detail.

• Biopsy. In some cases, we may take a small tissue sample from the tumor or cyst to analyze for the presence of cancer cells. Most children don’t need to have a biopsy, but we may use it to rule out cancer.

What causes pediatric benign bone tumors and cysts?

In most cases, the causes of benign bone cysts and bone tumors in children are unknown. Some children may develop osteochondromas as a result of a genetic disorder known as multiple hereditary exostoses (MHE). It’s important to understand that there’s nothing that you could have done or not done to prevent your child’s tumor or cyst.

How are pediatric benign bone tumors and cysts treated?

Once our orthopedic specialists confirm a diagnosis, we work closely with you and your child to develop a treatment plan. Most often, we recommend nonsurgical treatment if your child isn’t experiencing any symptoms. Nonsurgical treatment options include:

• Observation. We typically monitor your child with periodic X-rays to see if the tumor or cyst is growing. Depending on the type of tumor or cyst, your child may need X-rays every three to six months for two to three years or until they stop growing.

• Limits on high-impact activities. If there is a risk of fractures, we may recommend that your child avoid high-impact sports or other activities.

If symptoms worsen or the tumor or cyst is growing quickly, we may recommend surgery to remove the growth. Our orthopedic surgeons are experienced in procedures including:

• Curettage. In this procedure, our surgeons use special instruments to scrape tumors out of the bone.

• Aspiration. For bone cysts, our surgeons use a syringe to remove the fluid from a cyst.

• Bone-stimulating matrix. After curettage or aspiration, our surgeons fill the space with a bone-stimulating matrix to help stabilize the bone. Over time, the child’s bone tissue grows to replace the matrix.

• Excision. This procedure is surgery to remove tumors from the outside of a bone.

If your child needs surgery, their care team will provide you with complete instructions on how to prepare. We also plan follow-up care that includes a postsurgical visit two weeks later with an X-ray to check the bone.

If your child has a biopsy that shows that a bone tumor is cancerous, we coordinate their care with our bone cancer specialists. Learn more about our Pediatric Musculoskeletal Tumor Program.