American Urological Association - Neurofibroma
Home Education AUAUniversity Education Products & Resources Pathology for Urologists Urinary Bladder Mesenchymal and Other Tumors Neurofibroma


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  • Extremely rare, occur in patients with neurofibromatosis I.
    • GU is involved in ~20% in patients with neurofibromatosis.
    • Bladder is most commonly involved in GU tract, and involvement can be extensive.
  • Typically involves young patients (~1/3 pediatric patients); male>female (3:1).
  • Histology:
    • Mainly of plexiform type (involves multiple fascicles of nerve).
    • Loose spindle cells with tapered wavy nuclei (image A).
    • Associated with irregular collagen bundles ("shredded carrot" appearance) (image B).
    • No nuclear atypia or mitosis.
  • Immunohistochemistry: S100+.