Veterinary Society of
Surgical Oncology

General Considerations

  • synonyms: neurogenic sarcoma, neurofibrosarcoma, malignant Schwannoma, malignant neurolemmoma, and hemangiopericytoma
  • hemangiopericytoma may not exist as blood vessel pericyte origin has not been demonstrated and they have same histologic features as a peripheral nerve sheath tumor and stain positive with S-100 immunohistochemistry
  • female predisposition for hemangiopericytoma
  • sites: distal extremities are common
  • 3 groups of peripheral nerve sheath tumors:
  • peripheral (i.e., nerves away from the brain and spinal cord)
  • nerve root (i.e., nerves immediately adjacent to brain and spinal cord)
  • plexus (i.e., brachial or lumbrosacral)
  • peripheral form is more amenable to treatment than either the plexus or root forms
  • gross appearance: nodular, lobulated, or poorly defined without histologic encapsulation despite appearing encapsulated and discrete clinically
  • primary cutaneous neurofibroma is rare
  • solitary (common) or multiple (tortuous and nodular enlargement of nerve = neurofibromatosis)
  • adherence to deeper tissues and infiltration of underlying fascia, muscle, and skin is common
  • axial peripheral nerve sheath tumors can cause nodular enlargement and compress adjacent nerves causing unilateral lameness, muscle atrophy, paralysis, and pain with spinal cord invasion possible in up to 50% if grade III STS
  • metastatic rate: 10%-20% for grade I and 50% for grade III
  • peripheral nerve sheath tumor site:
  • nerve root: 72% local tumor recurrence rate with a median DFI 7.5 months and MST 12 months
  • plexus: 72% local tumor recurrence rate with a median DFI 1 month and MST 5 month

See Soft Tissue Sarcoma for more information

PERIPHERAL NERVE SHEATH TUMOR

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