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What are alveolar soft part sarcomas?

Alveolar soft part sarcoma (ASPS) is a malignant soft tissue tumor — a tumor that starts in the soft connective tissues of the body such as fat, muscles or nerves. ASPS is slow-growing and usually starts in the legs or arms, although it can also be found in the head and neck. It can spread to other parts of the body and tends to come back years later. Alveolar soft part sarcoma is very rare in children and, because ASPS is slow-growing, it may be present for a while before you or your child notice any symptoms. The cause of alveolar soft part sarcoma is unknown but may be connected to genes. Alveolar soft part sarcoma is a serious condition requiring surgical removal of the tumor and, in some cases, radiation. Once the tumor is removed, children will need to attend ongoing survivorship follow-up care because the tumor can return.

Alveolar Soft Part Sarcoma | Symptoms & Causes

What are the symptoms of alveolar soft part sarcoma?

Because these tumors affect soft tissues, which are elastic and easily moved, a tumor may exist for a long time before being discovered, growing very large and pushing aside surrounding tissue.

The most common alveolar soft part sarcoma symptoms include:

  • Painless swelling or lump
  • Pain or soreness caused by compressed nerves or muscles
  • Limping or other difficulty using the legs and feet
  • Diminished range of motion in the affected area

Alveolar Soft Part Sarcoma | Diagnosis & Treatments

How are alveolar soft part sarcomas diagnosed?

In addition to a complete physical examination, doctors diagnose alveolar soft part sarcoma (ASPS) with:

After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.

How are alveolar soft part sarcomas treated?

Alveolar soft part sarcoma treatment may include surgery, radiation therapy, or arterial embolization.


Surgery is often a first step, allowing doctors to form a complete diagnosis of the tumor type and providing information on the stage of the disease. If your child’s leg or arm is affected, your child may receive limb-salvage surgery — to help preserve the limb by removing the tumor and wide margins of healthy tissue surrounding the tumor, rotationplasty — a partial amputation that preserves a cancer-free lower leg, attaches it to the thighbone, and uses the ankle as a knee joint or amputation surgery — which, in rare cases, may be necessary, for example, if it involves the nerves and blood vessels.

Radiation therapy

Radiation therapy can help stop the growth of abnormal cells in specific areas of the body. Radiation therapy uses high-energy rays from a specialized machine to damage or kill abnormal cells. Our doctors use precisely targeted and dosed radiation to kill cancer cells left behind after your child's surgery.

Arterial embolization

There is potential for blood loss during an operation to remove an alveolar soft part sarcoma because of the abnormal blood vessels that may be involved. As a result, surgery involves very careful planning. In some cases, before both you and your child's treatment team decide on surgery, a radiologist may perform a procedure called arterial embolization. This blocks the blood flow in the abnormal vessels that are involved with the tumor. This reduces the risk of bleeding during surgery. To determine whether your child can undergo arterial embolization without complications, your doctor may use an angiogram, a special x-ray that helps doctors to visualize the involved blood vessels. Alveolar soft part sarcoma is typically unresponsive to chemotherapy.

How we care for alveolar soft part sarcoma

Children and teens with alveolar soft part sarcoma are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center through our Bone and Soft Tissue Tumors Program. Our integrated pediatric oncology program offers the combined expertise of a leading cancer center and a world-renowned children’s hospital.

Alveolar Soft Part Sarcoma | Programs & Services