Home Education AUAUniversity Education Products & Resources Pathology for Urologists Retroperitoneum Schwannoma


Image A

Image B

  • Clinical: male = female; 20's to 50's.
  • Much more common in head and neck and flexor surfaces of the extremities than in retroperitoneum.
  • Majority has mutations in NF2 gene.
  • Majority are sporadic tumors.
  • A minority (10%) are associated with syndromes such as neurofibromatosis type 2, schwanommatosis and multiple meningiomas.
  • Usually single, slow growing, and rarely have pain or other neurological symptoms.

Image C

Image D

  • Gross:
    • Surrounded by a true capsule and is pink white.
    • May be small fusiform lesions or large eccentric masses (image A) & (image B).
    • Retroperitoneal tumors are larger and often show degenerative changes like cystic change, hemorrhage and calcifications.
  • Histology:
    • Hallmark of schwannoma (above, left) is alternating areas of cellular (Antoni A) and hypocellular (Antoni B) areas (image C).
    • Cells have twisted or wavy nuclei and indistinct cytoplasmic borders.
    • Verocay bodies are also common: consist of palisading nuclei that form two compact rows separated by fibrillary pink cytoplasm (image D).
  • Immunohistochemistry: Diffuse S100+ is characteristic.
  • Prognosis is excellent; malignant change is exceedingly rare.