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Bone and Soft Tissue Tumors

What are tumors?

Tumors are lumps of tissue that form when cells divide uncontrollably.

There are two general types of tumors.

Benign tumors are not cancerous and do not spread from their original (primary) location. They can, however, come back (recur) at their original location.

Malignant tumors are cancerous and have the potential to spread cancer cells to other parts of the body (metastasis).

When tumors start inside the skeleton, such as in the leg bones, the ribs or the arm bones, they are called bone tumors. When they start inside other tissues, such as muscles, fat and blood vessels, they are called soft tissue tumors.

Both bone tumors and soft tissue tumors can be either benign or malignant. When these tumors are cancerous, they are called sarcomas.

Benign bone tumors

Benign bone tumors are by far the most common type of tumors that grow within the skeleton.

Three types of benign bone tumors are found most often in children and teenagers:

  1. Nonossifying fibroma usually is found in the actively growing sections of long bones such as the thighbone (femur).
  2. Exostosis (osteochondroma) contains both bone and cartilage and usually grows in the thighbone, the shinbone (tibia) or the bone in the upper arm (humerus).
  3. Unicameral (simple) bone cysts are holes in the bone that fill with fluid and tissue. They usually occur in the bone in the upper arm or in the upper part of the thighbone.
Unicameral bone cysts
Unicameral bone cysts. Common locations (red) and incidence per decade of life (blue).

These tumors almost never become cancerous. Often they are not painful and do not require surgery. If your child does feel pain, he should see an orthopedic surgeon.

Sometimes benign bone tumors clear up on their own and only require that we watch them carefully, checking your child once or twice a year.

In some cases, however, a benign bone tumor can cause problems while it grows. It can weaken your child’s bone and make it more likely that the bone will break. Tumors also can press on nerves and cause pain.

In cases like these, your child may need surgery.

Malignant bone tumors

Malignant bone tumors start inside the bone and can spread cancer cells to other parts of the body, often through the blood to the lungs.

Among young patients, malignant bone tumors occur most often in teenagers. The two most common types of bone cancer in young people are osteosarcoma and Ewing sarcoma.

It is common for a child who has a malignant bone tumor to complain about pain for a month or two before seeing a doctor. But finding malignant bone tumors early is very important because early treatment is more likely to be successful.

A malignant bone tumor can destroy a limb. It also can be life threatening.

Soft tissue tumors

Extensive thigh hemangioma
Extensive thigh hemangioma. This large lesion involves much of the medial thigh muscles (red arrows).

Soft tissue tumors form in connective tissues, such as muscles, tendons, fat and skin. They can be benign or malignant.

There are many kinds of benign soft tissue tumors. Common benign soft tissue tumors in children are:

  • Fibromas, which usually occur in the hands and feet
  • Hemangiomas, masses of blood vessels that show up in many different places
  • Lipomas, which are made up of fat cells

Malignant soft tissue tumors are called sarcoma. Each type of sarcoma is named after the body tissue in which it forms.

Rhabdomyosarcoma forms in the skeletal muscle and is the most common soft tissue sarcoma in children.

How do you diagnose bone and soft tissue tumors?

Rhabdomyosarcoma age distribution
Rhabdomyosarcoma age distribution. These tumors are common in infancy and early childhood. They can extend to bone (arrow).

The process we use to diagnose your child’s tumor depends on what we find out as we explore his condition.

In nine out of 10 children, for example, we can see and evaluate benign bone tumors simply by taking an X-ray of the bone.

If an X-ray does not provide enough information about a tumor, whether it is in bone or in soft tissue, we may ask your child to have more extensive imaging tests, starting with an MRI.

Synovial sarcoma
This lesion in a 16-year old boy involving the elbow joint is hard to see on conventional radiographs but readily imaged by MRI (red arrow).

If we suspect your child may have a malignant bone tumor, we will also ask him to have a bone scan as well as a CT scan of his lungs to make sure tumors have not spread there.

If your child has a soft tissue tumor, we may ask him to have a PET scan to help us judge how fast the tumor is growing.

If these imaging tests suggest to us that the tumor may be malignant, we will ask your child to have a tumor biopsy. In the hospital, a doctor will remove a small piece of the tumor and examine it under a microscope for signs of cancer.

Who gets bone and soft tissue tumors?

We do not know exactly what causes children to develop these tumors. For example, benign bone tumors are not inherited, except for the tumor called exostosis.

Osteosarcoma
Osteosarcoma. Common (red) and less common (orange) locations are shown. The age of onset in decades is shown in blue.

And only about two in every 10 children who get malignant bone tumors have a family history of the condition.

Children between the ages of 6 and 12 are the most likely to develop benign bone tumors, although the tumors sometimes show up in children as young as age 2.

Exostosis tumors are slightly more common in boys than girls.

The bone cancers osteosarcoma and Ewing sarcoma usually begin when children are young teenagers, a time when their bones are growing very rapidly and they often are taking part in sports and other physical activities.

The most common age at which children are diagnosed with these cancers is 14.

Boys are slightly more likely to get a malignant bone tumor than girls.

Malignant soft tissue tumors are more common in teenagers. Children who are younger than age 6 are most likely to get benign soft tissue tumors.

What is your experience with bone and soft tissue tumors?

To ensure that your child’s diagnosis and treatment is the best it can be, it is important to choose a medical center and doctors who specialize in pediatric bone and soft tissue tumors.

Ewing sarcoma
Ewing sarcoma. Common (red) and less common (orange) locations are shown. The age of onset in decades is shown in blue.

Children’s Hospital has the first clinic in the United States where doctors who specialize in bones, joints and muscles (orthopedists) and specialists in cancer (oncologists) work together in the same program. They are called a multidisciplinary team, and these teams are an important part of Children’s care.

For 20 years, our multidisciplinary team of doctors, nurses and staff in the Bone Tumor and Sarcoma Clinic has specialized in diagnosing tumors and providing exceptional care for children.

Each year we see about 350 new patients at our Bone Tumor and Sarcoma Clinic. About 90% of them have benign bone tumors.

Between 30 and 40 of the children we treat every year have new malignant bone tumors, and each year we diagnose and care for about 30 children with malignant soft tissue tumors.

Our patients are referred to us from throughout North America. We see our patients within one week of the call for an appointment and develop a plan for treatment at the first visit.

While our clinic is specifically for children, we work closely with adult sarcoma programs. We share expertise and access to highly sophisticated equipment with UW Medicine.

We also work closely with Fred Hutchinson Cancer Research Center and the Northwest Tissue Center.

How do you treat bone and soft tissue tumors?

Your child’s treatment will depend on several factors, including the type of tumor he has, the progress of the tumor and his medical history.

Treating benign bone tumors

Some benign bone tumors need only to be checked once a year and may clear up on their own. Sometimes children with benign bone tumors need to wear a brace, splint or boot for four to six weeks to allow their bones to heal.

If your child needs surgery, we often can use techniques that are not as hard on the child as more traditional operations.

These newer, less invasive techniques do not require your child to stay in the hospital. They include radiofrequency ablation and cyst injections.

Radiofrequency ablation

In radiofrequency ablation, the doctor inserts a tiny needle into the tumor. The needle contains wires that transmit an electrical current. The current heats the tumor to a high temperature and destroys it.

Doctors most often use radiofrequency ablation to treat a tumor called osteoid osteoma.

In most cases, your child can go home after the procedure and will be able to resume his usual activities right away.

Cyst injections

Unicameral bone cyst
Treatment by injection of unicameral bone cyst.

We can sometimes heal unicameral cysts by injecting them with a drug called a steroid, and with bone marrow or bone matrix.

If the doctor is using bone marrow, he will take the material from your child’s pelvis while your child is under anesthesia so that your child will feel no pain. Bone matrix comes from healthy human donors through the Northwest Tissue Center.

To inject the cyst, the doctor first inserts needles into the cyst and removes liquid. Next, he fills the cyst with a contrast fluid that helps him see if the cyst is benign and contains no tumor tissue.

If it is benign, he injects a paste of the steroid and bone marrow or bone matrix.

This treatment works because the steroid calms down the cyst while the bone marrow or bone matrix paste make bone to fill the hole.

Usually, a single injection heals the cyst only partially, so we must repeat the procedure. Your child may go through this procedure every few months for six months to a year.

Curettage and bone grafting

The main operation for benign bone tumors is a procedure that scrapes the tumor out of the bone (curretage) and fills the hole left behind with a bone graft.

The graft most often comes from the bone bank (allograft), so your child does not have to have another surgical procedure to get the graft from his own bone.

Children’s Hospital works with a special bone bank, the Northwest Tissue Center. The bone grafts we use come from healthy donors and are carefully screened for diseases.

It usually takes about four to six weeks for children to heal after this procedure. In many cases, children use crutches and a brace, splint or boot to protect their bones while they heal.

After treatment for benign bone tumors

No matter which treatment your child has, we will monitor his progress. Benign bone tumors have a significant risk of coming back (recurrence) after surgery, so it is important to keep an eye on your child’s condition.

In some cases, children have to have more than one treatment.

If your child has the curettage and bone grafting procedure, we provide physical therapy to help him return to his usual activities. Generally children recover from this surgery in two to three months.

Treating malignant bone tumors

In most cases of malignant bone tumors, children have surgery to take them out. The kind of surgery depends upon the size of the tumor, where it is located and whether the cancer cells have spread.

In the past, some children had amputations for malignant bone tumors. Now, children rarely have to undergo amputations. Most of the time, doctors can remove only the part of the bone that is affected by the tumor.

Limb-sparing surgery

The director of our Department of Orthopedics and chief of our Bone Cancer and Sarcoma Clinic, Dr. Ernest “Chappie” U. Conrad, has been a pioneer in developing techniques to save the limbs of children with malignant bone tumors.

In limb-sparing surgery, also called limb salvage, the doctor removes the tumor and any bone and cartilage affected by it, but leaves the surrounding nerves, muscles and tendons so that your child can keep his leg or arm.

Depending on the location of the tumor, the bone that the doctor removes is replaced by a bone transplant or a metal implant, such as a knee joint replacement.

Children younger than age 12, who have more growing ahead of them than older children, need an additional operation that will lengthen their limb so that it keeps pace with their growth as they get older.

Limb-sparing surgery is complex, and it requires doctors to make careful decisions about which children are likely to respond well to the operation.

Learn more about limb-sparing surgery.

Amputation

In rare cases — for about two or three out of every 100 patients — doctors have to remove (amputate) a limb to remove the tumor. Doctors most often do it because the tumor is unusually large or is likely to come back.

This shows why early treatment is so important. It is best to treat the tumor before it gets big.

Children who have amputations can do almost anything they want to do. Using an artificial limb (prosthesis), they can play sports and be active. Read more about our orthotics and prosthetics services.

After surgery for malignant bone tumors

Whether your child has limb-sparing surgery or an amputation, he will have extensive physical therapy after his treatment. If he has had limb-sparing surgery, he most likely will use crutches for three to six months while his bone graft or implant heals.

Children who have leg amputations can walk on their new prosthesis within three months. At Children’s, we provide prostheses and help with your child’s adjustments.

Treating soft tissue tumors

If a benign soft tissue tumor is painful or growing larger, your child may need to have it removed. Some painless tumors, however, we simply watch for changes.

If your child has a malignant soft tissue tumor, it must be treated. The expertise of our staff stretches from diagnosis to rehabilitation.

We use special techniques to get the best information about your child’s tumor. Within two months of beginning chemotherapy treatment, for example, your child will most likely have a PET scan.

This imaging test allows us to judge how fast a tumor is growing and whether the chemotherapy is working to slow its growth or shrink it.

Our clinic provides chemotherapy to reduce the size of soft tissue sarcomas before we do surgery. We also use radiation therapy, a treatment that uses high-energy rays emitted by a special machine to destroy cancer cells and shrink tumors.

We use surgery to remove malignant soft tissue tumors. Together, these treatments can be very successful in helping your child.

Surgery for soft tissue tumors

During the operation for a soft tissue tumor, the doctor removes the tumor. He may have to remove muscle along with the tumor, but your child most likely will not have a serious loss of strength.

After surgery, your child may have physical therapy to regain strength, movement and confidence.