Soft Tissue Tumors

Children
Adults

Children

Rhabdomyosarcoma is a type of cancer that occurs in the muscles. It is the most common of the soft tissue tumors diagnosed in children. It can occur anywhere in the body, but most commonly originates in the head and neck region. Only about 15 percent of rhabdomysosarcomas occur in the extremities (arms, elbow, legs, knee, thigh, foot, or shoulder). Rhabdomyosarcoma accounts for approximately five percent of all childhood cancers and more than half of the soft tissue sarcomas diagnosed in children. The disease can occur anytime throughout childhood but is most commonly diagnosed in children under age six.

There is a slightly higher incidence of rhabdomyosarcoma among boys. In addition, there is a higher incidence of the disease among children exposed to chemicals and chemical pollution and whose fathers are cigarette smokers.

Rhabdomyosarcoma is one disease that occurs in families with a cancer-related syndrome called Li-Fraumeni syndrome. However, most families of patients with rhabdomyosarcoma do not appear to be affected by the syndrome.

Rhabdomyosarcomas are typically classified into four types:

• embryonal - The most common type and is most frequently seen in head and neck and genitourinary tumors.
• botryoid - A variation of the embryonal type that most frequently arises as polyp or grape-like lesions in the genitourinary tract.
• alveolar - This more aggressive form of the disease is most often found in the extremities or trunk.
• pleomorphic - This rarest form of the disease typically occurs in the extremities or trunk.

Standard treatment for rhabdomyosarcoma includes chemotherapy (the use of anticancer drugs and/or compounds that travel via the bloodstream throughout the body to kill cancer cells) and radiation therapy (the use of specifically-targeted x-ray beams to kill cancer cells). Any residual rhabdomyosarcoma is removed with surgery.

Adults

Some of the most common soft-tissue sarcomas occurring in adults include:

• Malignant fibrous histiocytoma (MFH)
• Liposarcoma
• Synovial sarcoma
• Fibrosarcoma
• Vascular tumors
• Epithelioid sarcoma
• Clear cell sarcoma

These sarcomas can occur in the soft tissues throughout the body. They are most commonly found in the arms and legs. Soft-tissue sarcomas in adults are generally treated with radiation and surgery. At Johns Hopkins, radiation is the first stage of therapy and surgery follows. Our experts use radiation first since lower doses are required to cover the area of the tumor than after surgery. Higher doses of radiation are required if performed after surgery since the entire surgical field is a wider area than the original tumor. The goal is to expose less tissue to toxic radiation. One caveat to performing radiation first is that wound problems may be worse in radiated tissues that need to be surgically removed. For this reason, plastic surgeons are often included in the surgical team to reconstruct defects in the remaining tissues of soft-tissue sarcoma patients after surgical resection of the tumor.

Some soft tissue sarcomas such as synovial sarcoma, rhabdomyosarcoma, clear cell sarcoma, and epithelioid sarcoma can metastasize (spread of the tumor cells through the bloodstream) to the lymph nodes, usually in the same extremity where the tumor started. If a lump is felt in the lymph node area, a sentinel lymph node biopsy can be performed. This is a relatively new procedure to determine if the main lymph node in that area contains cancer. It involves a very small incision and avoids a complete lymph node removal and resultant edema (chronic swelling of that extremity) while still determining the status of the cancer. Only if the sentinel lymph node contains cancer will the remaining nodes be removed.

There is much debate surrounding whether adult soft-tissue sarcoma patients should receive chemotherapy. Patients with high-grade disease have a 50 percent chance of developing metastases to the lungs. Standard chemotherapy drugs are the only additional therapies available to kill cancer cells in the bloodstream, but have not proven effective in most cases. To find new drugs that target these specific cancers, researchers are collecting sarcoma tissues and comparing the cancer's genetic qualities that may lend themselves to emerging targeted therapies.