Rhabdomyosarcoma - symptoms, signs and treatment of rhabdomyosarcoma
A rhabdomyosarcoma is a tumor that develops from embryonic mesenchymal cells that can potentially differentiate into skeletal muscle cells. It can develop from virtually any type of muscle tissue of any localization, which leads to highly variable clinical manifestations. Tumors are usually detected with CT or MRI, confirm the diagnosis by biopsy. Treatment includes surgery, radiation therapy and chemotherapy.
Rhabdomyosarcoma is the 3rd most common tumor in children outside the central nervous system. Nevertheless, it accounts for only 3-4% in the structure of tumors in children. The incidence of rhabdomyosar-coma in children is 4.3 / million per year. Two thirds of tumors are detected in children under 7 years of age. The disease is more common among whites than blacks and somewhat more common in boys than in girls.
Two main histological subtypes are known: an embryonic variant that is characterized by loss of heterozygosity on the chromosome of 11 p15.5, and an alveolar subtype with translocation encompassing PAX3 or PAX7, transcription regulators during neuromuscular development. Although rhabdomyosarcoma can develop almost anywhere, there is a tendency to some variants of localization. The most common are the head and neck, accounting for 35-40% of primary tumors, the genitourinary system in 25% of cases and limbs in 20% of cases. Less than 25% of children in the manifestation of metastatic tumors.
Rhabdomyosarcoma - symptoms and signs
Children usually do not have systemic symptoms, such as fever, night sweats, or weight loss. In general, in children, the first manifestation is the appearance of a dense palpable mass or an organ dysfunction due to the destruction of the organ by a tumor.
Tumors of the orbit and nasopharynx are the most common in school-age children. Eye socket tumors can cause tearing, eye pain, or ptosis. Tumors of the nasopharynx can cause hyperemia of the nose, changes in the voice or mucopurulent discharge from the nose.
Tumors of the genitourinary system usually occur in infants and children of the first years of life; children have abdominal pain, palpable mass in the abdominal cavity, difficulty urinating and hematuria. Limb tumors are most common among adolescents; they appear as dense uniform formations located on the arms or legs. Metastases often develop in limb tumors, especially in the lungs, bone marrow and lymph nodes, and usually do not manifest clinically.
Rhabdomyosarcoma - diagnosis
CT is used for diagnosis, although in case of lesions of the neck and head, the tumor is better defined by MRI. The diagnosis is confirmed in the study of biopsy or a removed tumor. Standard screening for the detection of metastases includes chest CT, bone X-ray and bone marrow puncture or trepanobio-psion.
Prognosis and treatment of rhabdomyosarcoma
The prognosis is based on the localization of the tumor, the prevalence of resection and the presence of metastases. Other important prognostic factors are age and histology. Combinations of these prognostic factors place the child in one of 3 risk categories: low, medium or high.Treatment is more intensive with risk category 3, and overall survival varies from more than 90% in children with a low-risk tumor to less than 50% in children with a high-risk tumor.
The treatment consists of surgery, radiation therapy and chemotherapy. Complete excision of the primary tumor is recommended if it can be done safely. Since the tumor is sensitive to chemotherapy and radiation therapy, aggressive resection is not supported if it can damage the organ or impair its function. Children of all risk categories are treated with chemotherapy; the most commonly used drugs are vincristine, actinomycin D, cyclophosphamide, doxorubicin, ifos-famid, and etoposide. Radiation therapy is usually used for children with residual tumors after surgery, as well as for children with medium and high risk categories.