Veterinary Society of
Surgical Oncology

General Considerations

  • types: neuronoma, neurolemmoma, Schwannoma, malignant Schwannoma, neurofibroma, and neurofibrosarcoma
  • peripheral nerve sheath tumor is preferred Schwann cells are origin and all have similar biologic behaviour
  • fibrous, osteoid, chondroid, myxoid, and squamous patterns may be observed due to tumor differentiation
  • peripheral nerve sheath tumor commonly involve nerve roots of the brachial plexus
  • tumor progression occurs proximally and distally and may involve the spinal cord
  • metastatic disease is rare although pulmonary metastasis has been reported

Peripheral Nerve Sheath Tumor Classification

  • peripheral nerve sheath tumor classified according to level of involvement as:
  • peripheral: tumor involvement distal to brachial or lumbrosacral plexus
  • plexus: tumor involvement of nerves in brachial or lumbrosacral plexus and spinal nerves distal to intervertebral foramina
  • root: tumor involvement of ventral or dorsal nerve roots or tumor entering intervertebral foramina

Clinical Features

  • clinical signs are slowly progressive
  • lameness (77%) and muscle atrophy (93%) are common with pain and palpable mass other findings

Diagnosis

  • clinical signs and physical examination
  • advanced imaging using CT and MRI provides an indication of level of involvement and associated changes
  • myelography recommended for suspected spinal nerve root involvement
  • EMG useful in delineating nerve root involvement
  • CSF rarely useful

Treatment

  • surgical treatment is recommended with technique depending on location:
  • local resection
  • amputation
  • laminectomy
  • combination of these procedures

Prognosis

  • prognosis depends on level of involvement and ability for complete surgical resection
  • excellent prognosis for peripheral classification of peripheral nerve sheath tumors due to ability for complete resection with no death related to tumor
  • poor prognosis for plexus and root peripheral nerve sheath tumors with death due to tumor in 78%
  • no significant differences between plexus and root groups although trend for plexus tumors to survive longer

PERIPHERAL NERVE TUMORS

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