Alveolar Rhabdomyosarcoma: A type of rhabdomyosarcoma, a fast-growing malignancy of muscle that mainly affects children (more than 60% of cases are diagnosed before age 10) but can occur at any age. Treatment includes surgery, radiotherapy, chemotherapy, and most often, a combination of these modes of treatment. The outlook depends on a number of factors, including the original location of the tumor.
There are two main types of rhabdomyosarcoma that occur in children: alveolar and embryonal. These are determined based upon microscopic examination of the tumor tissue. Embryonal rhabdomyosarcoma is most common and usually occurs in the head and neck area or in the genital or urinary organs. Alveolar rhabdomyosarcoma occurs most often in the arms or legs, chest, abdomen, genital organs, or anal area. A third type, known as anaplastic rhabdomyosarcoma, does not commonly develop in children.