Embryonal Rhabdomyosarcoma in a Young Boy

* To whom correspondence should be addressed: Wendy Kar Yee Ng Tel: (519) 639-9128 E-mail: [email protected] INTRODUCTION Soft tissue tumours are classified according to the tissue they appear as: such as muscle, fat, fibrous tissue, vessels and nerves. Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood and adolescence, and is a skeletal muscle tumour. It occurs in any anatomic location, although mostly in the head, neck or genitourinary tract where there is normally relatively little skeletal muscle involved (1). Skeletal muscle is only involved in the body extremities (2). Rhabdomyosarcoma is malignant; in contrast, the benign variant, rhabdomyoma, is very rare. Rhabdomyosarcoma tends to present as an expanding mass, resulting in pain and symptoms related to the compression of nearby structures. Metastases can lead to pain in the bones, difficulty with respiration due to lung nodules or pleural effusion, anemia, thrombocytopenia, and neutropenia, with 5-year survival rate less than 30% (3). In contrast, confined disease treated with combined surgery, radiation and chemotherapy has a 5-year survival rate of over 80% (3). The incidence of rhabdomyosarcoma is 6 cases per 100,000 per year in the United States, and approximately 87% of patients are under 15 years of age (3). It is valuable for medical students to understand an example of a clinical case of pediatric embryonal rhabdomyosarcoma. An awareness of the typical investigations and the general prognosis in a case of pediatric embryonal rhabdomyosarcoma allows medical students to consider this type of tumour in their differential diagnoses, when appropriate.