Pediatric Rhabdomyosarcoma

Synonyms

2

Overview

Pdediatric rhabdomyosarcoma (Childhood rhabdomyosarcoma, RMS) is the most common soft tissue sarcoma in children.The name is derived from the Greek words rhabdo, which means rod shape, and myo, which means muscle. Although Weber first described rhabdomyosarcoma in 1854, a clear histologic definition was not available until 1946, when Stout recognized the distinct morphology of rhabdomyoblasts. Stout described rhabdomyoblasts as appearing in round, strap, racquet, and spider forms. As its name suggests, the tumor is believed to arise from a primitive muscle cells. Rhabdomyoblasts sometimes have discernible muscle striations that are visible on specimens under light microscopy, although electron microscopy may be needed to detect subcellular elements. Cells are usually positive for intermediate filaments and other proteins typical of differentiated muscle cells, such as desmin, vimentin, myoglobin, actin, and transcription factor myoD.

Symptoms

The symptoms of pediatric rhabdomyosarcoma are visible and prominent and include:

Swollen red lumps where the cancer starts developing, the lumps are hard and can grow in size unless treated.

Other symptoms include:

• Poor bowel movements,
• Blood in the urine,
• Secretions from the genitals and nose, 
• Headaches.

Causes

The cause of rhabdomyosarcoma is unclear. Several genetic syndromes and environmental factors are associated with increased prevalence of rhabdomyosarcoma. Genetic syndromes include the following: Neurofibromatosis (4-5% risk of any one of numerous malignancies), Li-Fraumeni syndrome (germline mutation of the tumor suppressor gene TP53), Rubinstein-Taybi syndrome, Gorlin basal cell nevus syndrome, Beckwith-Wiedemann syndrome, Costello syndrome9 A higher prevalence of congenital anomalies are observed in patients who later develop rhabdomyosarcoma with locations as follows: Genitourinary (GU) tract,CNS (ie, Arnold-Chiari malformation), GI tract, Cardiovascular system Environmental factors appear to influence the development of rhabdomyosarcoma, as follows: Parental use of marijuana and cocaine, Intrauterine exposure to X-rays, Previous exposure to alkylating agents.

Diagnosis

Various tests can determine whether these related symptoms indicate childhood rhabdomyosarcoma. CT, X-ray, MRI, bone scans, and Ultrasounds may be performed to identify the location and size of the cancer. Biopsies of the lump can be taken along with bone marrow biopsies to detect whether the cancer has spread within the marrow, the bone, and the blood supply. Further determination of how aggressive and large the cancer is requires these scans.

Prognosis

Pediatric rhabdomyosarcoma has been fatal. Recovery rates have increased by 50 percent since 1975. In children five years of age or younger survival rates are up to 65 percent. In adolescents younger than 15 years old, the survival rate has increased up to 30 percent.

Treatment

Determination of treatment options depends on certain factors, some of which affect internal organs and others that affect personal appearance. When determining treatment, oncologists consider the initial location the tumor, the likelihood of body function deterioration, the effect on appearance, and the patient's potential response to chemotherapy and radiation. Surgery is the least successful of the treatment options; the tumor cannot be completely removed because it develops within the cells. Chemotherapy follows surgery to shrink or eliminate the remaining cancer cells.

Stem cell research under clinical trial shows promise to replace lost cells.

The aggressiveness of this cancer requires the response of a large team of specialists, possibly including a pediatric surgeon, oncologist, hematologist, specialty nurse, and rehabilitation specialists. Social workers and psychologists aid recovery by building a system of emotional support. Treatment is harsh on the body and may result in side effects including mood swings, learning difficulties, memory loss, physical deformations or restrictions, and potential risk of secondary cancers.