Bone Tumors and Soft Tissue Tumors

Benign bone tumors are much more common than malignant bone tumors, and they almost never become cancerous.

These types of benign bone tumors are found most often in children and young adults:

• Nonossifying fibromas are usually found in long bones that are still growing, such as the thighbone (femur).
• Exostoses or osteochondromas contain both bone and cartilage and usually grow out from a bone.
• Unicameral bone cysts are holes in a bone that fill with fluid. They are most common in the upper arm bone (humerus) and the upper thighbone. They are also called simple or solitary bone cysts.

Read more about types of benign bone tumors (PDF) (Spanish).

There are many types of benign soft tissue tumors. They are much more common than cancerous soft tissue tumors.

These are the common types of benign soft tissue tumors in children:

• Fibromas usually happen in the hands and feet.
• Lipomas and lipoblastomas are made up of fat cells.
• Neurofibromas and schwannomas grow in nerves branching off the spinal cord.

Vascular malformations look like tumors but are not. They are collections of abnormal blood or lymphatic vessels.

Malignant bone tumors start inside the bone. They can spread cancer cells to other parts of the body, often through the blood, to the lungs or other bones. Bone cancer can put your child’s limb and life at risk.

These are the most common types of bone cancer in young people:

• Osteosarcoma can start in any bone in the body. In children, it most often starts near the knee. Usually, the tumor cells make abnormal bone. Sometimes osteosarcoma spreads to other bones or the lungs.
• Ewing sarcoma, which is less common, can also start in any bone. Sometimes it spreads to other bones or the lungs.  

Malignant soft tissue tumors (soft tissue sarcomas) are less common in children than in adults.

These cancers can start in any of the soft tissues that connect or support other structures. These tissues include muscles, tendons, fat, blood vessels, lymphatic vessels, nerves and the soft tissues in and around joints. We treat all types of soft tissue sarcoma in children.

Rhabdomyosarcoma (rab-doe-my-o-sar-ko-ma) is the most common type. This cancer can happen in almost any muscle of the body. A child who develops rhabdomyosarcoma at a young age may have a cancer predisposition syndrome. Our Cancer Predisposition Clinic screens and cares for children born with these syndromes.

The most common symptom of bone tumors is pain.

• Your child may feel like the pain is in a bone or joint.
• The pain may get worse over time.
• The pain can happen at night or when your child is resting.

It is common for a child who has a malignant bone tumor to complain about pain for months before seeing a doctor.

Sometimes, benign bone tumors are not painful. They may cause pain if they weaken the bone or rub on nerves or tendons.

Bone tumors may also cause:

• A lump
• Swelling
• A broken bone

Bone tumors in the spine may cause:

• Muscle weakness
• Tingling or numbness in the legs
• Problems with bowel or bladder control

The most common symptom of soft tissue tumors is a lump or mass. These tumors may or may not cause any pain.

Cancer in a muscle often causes a lump that grows quickly.

Other symptoms may depend on where the tumor is. For example:

• A tumor in or around the urinary tract can cause problems with peeing (urination).
• A tumor at the base of the skull can press on nerves, causing weakness or pain in the head or face.

The doctor may want to have pictures taken of the inside of your child’s body (imaging studies).

Often, we can see and assess benign bone tumors by taking an X-ray of the bone.

If an X-ray does not give enough information about your child’s tumor, we may use:

• MRI (magnetic resonance imaging) scan
• CT (computed tomography) scan
• PET (positron emission tomography) scan
• Ultrasound

If imaging studies suggest that the tumor may be cancer, your child will have a biopsy. In the hospital, surgeons will cut out a small piece of the tumor and check it under a microscope for signs of cancer. This test is important to tell the type of tumor and help us plan treatment.

Our surgeons use extra care when doing the biopsy to avoid the risk of spreading the tumor cells. In certain cases, our surgeons or interventional radiologists do a biopsy using a needle instead of with surgery.

Doctors may use anticancer medicine (chemotherapy):

• As your child’s main treatment for bone cancer
• Before surgery to shrink or kill a tumor
• After surgery to kill any cancer cells that might remain
• Both before and after surgery

The kind of medicines and how long they are given depend on the type of cancer your child has.

We check your child with imaging studies and physical exams to see if the chemotherapy is working to slow tumor growth or shrink it.

Children with sarcomas receive chemotherapy at our Seattle hospital campus in:

• Our 48-bed Cancer and Blood Disorders Center – Inpatient (as an inpatient)
• The outpatient infusion unit (by clinic appointments as an outpatient)

See more about getting chemotherapy at Seattle Children’s.

The kind of surgery done for bone cancer depends on:

• The size of the tumor
• Where it is located
• If the cancer cells have spread

Our surgeons are skilled and experienced in doing many types of procedures. These include:

• Limb-sparing surgery, where surgeons remove the tumor and any bone and cartilage affected by it. This usually leaves the nerves, muscles and tendons around the area so that your child can keep their leg or arm. This is also called limb salvage. Depending on where the tumor is, the surgeon may use a bone transplant (also known as a bone graft) or a metal implant, such as a special type of joint replacement, to replace the bone that was removed. Some of these joint replacements can be made longer to match a child’s or teen’s growth.
• Amputation, where surgeons remove large parts of an arm or leg. Sometimes we amputate because of the size or location of the tumor. But sometimes patients choose it over other options. For many, this is best for disease control and for keeping active after they get better. After an amputation, we can fit your child with an artificial limb (prosthesis) and help them adjust to using it.
• Rotationplasty, a unique way to rebuild a child’s leg after part of it has been removed because of cancer around the knee. After removing the part affected by cancer, surgeons reattach the healthy lower leg at the thigh, facing backward. With a lower-leg prosthesis, the backward ankle works like a knee joint. For some growing children, this is the best choice for staying active and playing sports.

Radiation therapy uses a machine to send high-energy beams to destroy cancer cells and shrink tumors. Doctors aim the radiation at the place where they know or suspect there is cancer.

Radiation therapy works well to shrink or kill many types of tumors. Doctors sometimes use radiation before surgery so the tumor is easier to remove or after surgery to kill any cancer cells that may still be in the body.

The best radiation treatment for your child depends on their tumor. Our options include proton therapy, which may be better for tumors in places where side effects of treatment tend to be serious or lasting. We offer this treatment through our partner, Fred Hutchinson Cancer Center, which has the only proton therapy center in the Northwest.

Learn more about Seattle Children’s Radiation Therapy Service.

No matter which treatment your child has, they will have extensive physical therapy to improve their flexibility and mobility. This will help them return to their usual activities. The physical therapist (PT) uses play and exercise to help build strength and coordination and reduce pain.

Some children may need crutches or other adaptive equipment after surgery. Our occupational therapists (OTs) help your child learn to use equipment. The OT can show your child new ways to do tasks of daily life, if needed.

Our doctors use chemotherapy to reduce the size of soft tissue sarcomas before surgery. In some cases, doctors give chemotherapy after surgery to kill any cancer cells that may still be in the body.

The kinds of medicines and length of treatment depend on the type of cancer your child has. Researchers are studying new mixes of medicines to find the best mix for each type of disease.

To check if the chemotherapy is working to shrink the tumor or slow its growth, we do regular physical exams and imaging studies.

Our patients receive chemotherapy at our hospital campus in Seattle. They may stay overnight in our Cancer and Blood Disorders Center – Inpatient or get treatment at our outpatient infusion unit without having to stay overnight.

See more about getting chemotherapy at Seattle Children’s.

We use radiation therapy to treat some soft tissue sarcomas. Your child might have radiation therapy before or after surgery, or they might have radiation therapy on its own.

The best radiation treatment for your child depends on their tumor. Our options include proton therapy, offered at Fred Hutch Proton Therapy, the only proton therapy center in the Northwest.

Learn more about Seattle Children’s Radiation Therapy Service.

During surgery, we remove as much of the tumor as possible, along with some of the healthy tissue around it. For larger tumors in certain parts of the body, our orthopedic and oncology surgeons work with our plastic surgeons to do complex reconstructive surgery to improve how your child’s body works or how it looks after their tumor is removed.

After surgery, your child may have physical therapy.

We do genetic testing if your child’s tumor:

• Is a type linked to certain genetic changes
• Does not respond to treatment
• Comes back after treatment
• Has spread to other areas before treatment begins

If tests show that your child’s cancer is caused by the NTRK fusion or other specific genetic changes, their treatment options may include targeted therapy medicines.

Many of our patients with sarcomas take part in research studies of new treatments along with their standard treatment. These studies — called clinical or therapeutic trials — include studies of new medicines or new ways to combine medicines.

Your child’s doctor will talk with you about any new treatment options that might help your child. Then you can decide whether you want your child to take part.

The STRIvE and ENLIGHTen phase 1 trials may be an option for children and young adults with tumors that are difficult to treat (refractory) or that come back after treatment (relapsed). In these studies, researchers reprogram the body’s infection-fighting T cells to find and destroy cancer cells.

Learn more about cancer clinical trials at Seattle Children’s

• Find many clinical trials offered at Seattle Children’s on our Current Research Studies page or on ClinicalTrials.gov. Read our guide about searching for trials on ClinicalTrials.gov (PDF).
• Contact us at 206-987-2106.
• Email us.
• Read more about cancer research and clinical trials at Seattle Children’s.

• Seattle Children’s has surgeons trained in treating bone, muscle and joint problems in children (pediatric orthopedic surgeons). Some have specialized dual training in both pediatrics and tumors, including extra training in how to treat a wide range of syndromes that cause benign musculoskeletal tumors.
• Our Cancer and Blood Disorders team includes surgeons trained in treating malignant tumors that affect the soft tissue and bones (orthopedic oncology surgeons).
• In our Bone Tumor and Sarcoma Clinic, orthopedic surgeons work side by side with pediatric oncologists. The clinic team meets as a group each week to discuss each child’s care in detail. This way all our specialists can work together to provide the safest, most effective care for your child. Our team meetings keep us in close contact about how your child is doing.
• Bone and soft tissue tumors may affect many parts of the body. Depending on your child’s illness, their care team may also include general surgeons; neurosurgeons; ear, nose and throat (ENT) surgeons; urologists; gynecologists; or plastic surgeons. Other hospitals refer patients to us for tumors that are difficult to safely remove.
• If your child has cancer, they will benefit from the work of physician-scientists at Fred Hutchinson Cancer Center and UW Medicine, as well as at Seattle Children’s. The National Cancer Institute has named our partnership a comprehensive cancer center.

• We offer state-of-the-art treatments and clinical trials that other hospitals may not provide. Our advanced options for cancer include anticancer medicine (chemotherapy), surgeries of many kinds, various types of radiation therapy, targeted therapy and immunotherapy.
• Our surgeons are skilled in many types of special procedures, including rotationplasty and limb-sparing surgery. For some young children who have part of a leg removed, we use a “growing prosthesis” to lengthen their affected leg as they grow.
• For children who need radiation therapy for cancer, proton therapy may be an option. Proton therapy delivers radiation more precisely than X-rays. We offer this treatment at Fred Hutch Proton Therapy, the only proton therapy center in the Northwest.
• Children and young adults with malignant solid tumors that are difficult to treat (refractory) or that come back after treatment (relapsed) may be able to take part in clinical trials that boost the immune system with CAR T-cell therapy. Dr. Katie Albert leads the STRIvE and ENLIGHTen research studies.
• We offer many targeted therapies for cancer. One example is a new drug called Vitrakvi (pronounced vih-TRAK-vee) for children whose cancer cells have a genetic change called an NTRK gene fusion.

• The physician-scientists on our team do research to understand the genetics and biological pathways of sarcomas. The knowledge they gain helps us create new treatments.
• We have one of the nation’s largest pipelines of CAR T-cell immunotherapy trials for children and young adults and are involved in clinical trials for many other types of treatment.
• Seattle Children’s doctors are leaders in national research groups such as the Children’s Oncology Group (COG) and Sarcoma Alliance for Research Through Collaboration (SARC). COG is the world’s largest consortium of childhood cancer specialists.
• Read about orthopedics research and cancer research at Seattle Children’s.

• Our specialty is treating children’s disease while helping them grow up to be healthy and productive adults.
• Our team cares for your whole child. We don’t just treat their disease. As needed, your child will receive care from specialists in nutrition, pain management, palliative care, pharmacy, physical therapy and emotional health. Read more about the supportive care we offer.
• Treatment for these tumors may be very different for children than for adults because pediatric tumors respond to therapy in different ways than adult tumors. We plan your child’s treatment based on years of experience and the newest research on what works best — and most safely — for children. Our experts focus on how treatments today affect growing bodies in the future.
• We know that teens and young adults with cancer have different challenges than young children. Our Adolescent and Young Adult Cancer Program focuses on their needs. An important part of planning for life after cancer is protecting your ability to have biological children (fertility preservation).

• Learning that your child has a tumor can be scary. We help take positive steps right away by offering appointments soon, especially to children who might have cancer and need to be seen urgently.
• During visits, we take time to explain your child’s condition. We help you fully understand your treatment options and make the choices that are right for your family.
• Our doctors, nurses, Child Life specialists and social workers help your child and your family through the challenges of their illness. We connect you to community resources and support groups.
• At Seattle Children's, we work with children and families from around the Northwest and beyond. Whether you live nearby or far away, we can help with financial counseling, schooling, housing, transportation, interpreter services and spiritual care. Read about our services for patients and families.