Home Education AUAUniversity Education Products & Resources Pathology for Urologists Paratesticular Tumors Rhabdomyosarcoma


Image A

Image B

  • One of the most common non-GCTs of the pediatric population.
  • 60% of paratesticular RMS occurs in the first 2 decades of life.
  • Most often arises in the paratesticular region, involving the scrotal contents.
  • Vast majority is embryonal type; other types such as alveolar or pleomorphic types are exceedingly rare.
  • Gross: solid white-tan to yellowish gelatinous mass (image A).

Image C

Image D

  • Histology:
    • Strap cells or tadpole cells with cross-striations of the eosinophilic cytoplasm (rhabdomyoblasts) (image B), (image C), & (image D).
    • Variable mixture of rhabdomyoblasts and primitive cells (small round blue cells).
  • Immunohistochemistry: positive for skeletal muscle markers (Desmin+, MyoD1+ and myogenin+).
  • Favorable prognosis with therapy, better than those in other GU sites.
  • Large tumors in patients >10 years old has poorer prognosis.