Rhabdomyosarcoma
Definition
- Primitive malignant tumor of embryonal skeletal muscle progenitor cells (myoblasts)
Diagnostic Criteria
- Myogenin expression is essentially diagnostic
- Only exception is rare expression of myogenin by melanotic neuroectodermal tumor of infancy and the composite tumors listed below
- Malignant triton tumor (rhabdomyosarcoma plus malignant peripheral nerve sheath tumor)
- Ectomesenchymoma (rhabdomyosarcoma plus peripheral primitive neuroectodermal tumor)
- Malignant teratoma
- Carcinosarcoma
- Only exception is rare expression of myogenin by melanotic neuroectodermal tumor of infancy and the composite tumors listed below
- Rhabdomyosarcoma is predominantly a pediatric neoplasm
- Most common soft tissue sarcoma of childhood
- Up to 10% of all childhood malignancies
- Only sclerosing and pleomorphic types show significant adult incidence
- Most common soft tissue sarcoma of childhood
- Histologic types show markedly different clincal features
(select type for criteria)
- Embryonal (includes botryoid, spindled and NOS)
- Alveolar
- Mixed embryonal and alveolar
- Sclerosing
- Pleomorphic
- See Staging for IRSG modified TNM, do not use TNM from AJCC
Florette K. Gray Hazard MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: 10/25/12
