Alveolar Soft Part Sarcoma

Definition

Definition of Alveolar Soft Part Sarcoma
Alveolar soft part sarcoma, abbreviated ASPS, is a very rare type of soft tissue sarcoma, that grows slowly and whose cell of origin is unknown.

ASPS is a sarcoma, and that indicates that this cancer initially arises from embryonic mesenchyme. (The fertilized egg divides and redivides forming a sphere. Early in embryogenesis, dimples appear in the poles of the sphere and burrow through the sphere forming an inner passage that will ultimately form the gut. Malignancies arising from cells that were originally part of the outer layer of the sphere and those that were part of the embryonic tunnel are termed carcinomas; malignancies arising from the cells between the outer layer and the inner burrow are termed sarcomas.) Typically, ASPS arises in muscles and deep soft tissue of the thigh or the leg (lower extremities), but can also appear in the upper extremities (hands, neck, and head). While ASPS is a soft tissue sarcoma, it can also spread and grow inside the bones.

Symptoms

Symptoms of Alveolar Soft Part Sarcoma
Alveolar soft part sarcoma symptoms may either be a painless swelling or a soreness caused by compressed nerves or muscles affecting the range of motion in the affected area. ASPS can metastasize (spread and invade) into other organs of the body.

Causes

Causes of Alveolar Soft Part Sarcoma
Chromosomal analysis of ASPS shows the breaking and joining of two chromosomes in the tumor cells. A piece of chromosome X breaks and is joined to chromosome 17. This translocation creates a fusion between two genes named ASPL and TFE3, which results in the formation of an aberrant protein (termed fusion protein) that is not found in normal cells. Two sorts of fusions between chromosome X and chromosome 17 are found in different ASPS tumors: Type one, and type two. Dr. Ladanyi at Memorial Sloan-Kettering Cancer Center, in New York, has pioneered this work.

Diagnosis

Diagnosis of Alveolar Soft Part Sarcoma
Alveolar soft part sarcoma usually exists in a patient's body for years before being diagnosed. The cancer could grow and even push aside its surrounding tissues before it causes any discomfort. As such, ASPS symptoms are usually painless soreness or swelling caused by compressed muscles and nerves. These symptoms may affect the range of motion in the affected area.

Treatment

Treatment of Alveolar Soft Part Sarcoma
Surgery is the most common and effective treatment for most soft tissue sarcomas, particularly for alveolar soft part sarcoma that has not spread. These tumors tend to be unresponsive to chemotherapy.

Depending on the size and location of the tumor, your child may either need:

1. Limb-salvage surgery to help preserve the limb by removing the tumor and some healthy tissue around the tumor, or
2. Amputation, which may be necessary if the tumor cannot be removed (for example, if it involves the nerves and blood vessels).

Prognosis

Prognosis of Alveolar Soft Part Sarcoma
Although ASPS displays a relatively indolent course, the ultimate prognosis is poor and is often characterized by late metastases.

Prevention

Prevention of Alveolar Soft Part Sarcoma
Consult with your doctor.