Pediatric Head and Neck Rhabdomyosarcoma

• Etiology: Malignancy of mesenchymal origin which does not necessarily arise in muscle
• Imaging Orbital:
  — Unilateral
  — Extraconal
  — Usually well-circumscribed
  — Most often in medial-superior quadrant of orbit
  — If parameningeal in location look hard for CNS involvement
  — May have aggressive or non-aggressive or mixed effects on bone
• Imaging MRI:
  — T1WI: Hypointense to intermediate
  — T1WI post contrast: Enhances heterogeneously
  — T2WI: Intermediate to hyperintense
  — DWI: Restricted diffusion
• DDX: Infantile hemangioma
• Complications: Metastasis to lung
• Treatment:
• Clinical:
  — Most common sarcoma in children
  — Most common extraoccular orbital malignancy in childhood
  — In all ages with mean age 6-8 years old,
  — Orbital rhabdomyosarcoma has best prognosis of all head and neck rhabdomyosarcomas
  — 50% head and neck and 30% genitourinary and 20% musculoskeletal
  — Embryonal cell type seen in infants is most common
  — Alveolar cell type seen in older children and affects musculoskeletal system and is more aggressive
  — Orbital has best prognosis

Radiology Cases of Head and Neck Rhabdomyosarcoma