Canis ISSN: 2398-2942

Nerve sheath: neoplasia

Synonym(s): SchwannomaNeurofibromaNeurofibrosarcoma

Contributor(s): Rodney Bagley

Introduction

  • Peripheral nerve tumors represent approximately 25% of canine nervous system tumors.
  • Commonly involve middle to low cervical nerve roots, and brachial plexus.
  • They may also involve the trigeminal nerve, thoracic nerves and lumbosacral plexus.
  • Signs: usually of peripheral nerve deficits and muscle atrophy.
  • Diagnosis: signs, nerve biopsy.
  • Treatment: excision of tumor, steroids.
  • Prognosis: guarded - often not possible to excise tumor.

Pathogenesis

Etiology

  • Spinal neoplasia can occur in the extradural, intradural/extramedullary, and intramedullary spaces.
  • Extradural tumors are most common and include primary and secondary bone tumors (osteosarcoma, fibrosarcoma, chondrosarcoma), hemangiosarcoma, various carcinomas, multiple myeloma and other plasma cell tumors, lipomas, liposarcomas, and lymphosarcoma.
  • Intradural extramedullary tumors include meningiomas and nerve sheath tumors.
  • Meningiomas are most often found in the cervical area.
  • Nerve sheath tumors can occur at any level of the spinal cord, however, the thoracic limb nerves are often affected.
  • A high suspicion for this type of tumor should occur when a non-localizable lameness of a thoracic limb is found in an older dog.

Pathophysiology

  • Tumor of nerve sheaths which compromises function of affected nerves.
  • Tumor of nerve sheaths → interruption of nerve conduction → loss of function of target organ → muscle atrophy where skeletal muscle affected.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Anderson G M, Dallaire A, Miller L M & Miller C W (1999) Peripheral nerve sheath tumour of the diaphragm with osseous differentiation in a 1 year old dog. JAAHA 35 (4), 319-322 PubMed.
  • Carvalho G A, Nikkhah G, Matthies C et al (1997) Diagnosis of root avulsions in traumatic brachial plexus injuries: value of computerized tomography myelography and magnetic resonance imaging. J Neurosurg 86 (1), 69-76 PubMed.
  • Levy M S, Kapatkin A S, Patnaik A K et al (1997) Spinal tumors in 37 dogs - Clinical outcome and long-term survival (1987-1994). JAAHA 33 (4), 307-312 PubMed.
  • Brehm D M, Vite C H, Steinberg H S et al (1995) A retrospective evaluation of 51 cases of peripheral nerve sheath tumors in the dog. JAAHA 31 (4), 349-359 PubMed.
  • McCarthy R J, Feeney D A & Lipowitz A J (1993) Preoperative diagnosis of tumors of the brachial plexus by use of computed tomography in three dogs. JAVMA 202 (2), 291-294 PubMed.
  • Lipsitz D & Bailey C S (1992) Lateral approach for cervical spinal cord decompression. Prog Vet Neuro 3 (1), 39-44 VetMedResource.
  • Samardzic M, Grujicic D & Antunovic V (1992) Nerve transfer in brachial plexus traction injuries. J Neursurg 76 (2), 191-197 PubMed.
  • Sharp N J H (1988) Craniolateral approach to the canine brachial plexus. Vet Surg 17 (1), 18-21 PubMed.
  • Steinberg H S (1988) Brachial plexus injuries and dysfunction. Vet Clin North Am 18 (3), 565-580 VetMedResource.
  • Bailey C S (1984) Patterns of cutaneous anesthesia associated with brachial plexus avulsion in the dog. JAVMA 185 (8), 889-899 VetMedResource.
  • Griffiths I R (1974) Avulsion of the brachial plexus 1. Neuropathology of the spinal cord and peripherial nerves. JSAP 15 (3), 165-176 PubMed.
  • Griffiths I R, Duncan I D & Lawson D D (1974) Avulsion of the brachial plexus 2 - Clinical Aspects. JSAP 15 (3), 177-182 PubMed.


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