Canis ISSN: 2398-2942

Astrocytoma

Synonym(s): Glioblastoma, glioma

Contributor(s): William Brewer Jr, Phil Nicholls

Introduction

  • Dogs develop various brain tumors Brain: neoplasia , most commonly meningioma Meningioma or gliomas.
  • Most studies report meningiomas as the most frequent brain tumor in dogs however some studies found gliomas to be the most frequent.
  • Gliomas are tumors of the supporting (glial) non-neuronal cells: astrocytes, oligodendrocytes, microglia. An astrocytoma is a glioma arising from astrocytes.

Pathogenesis

Etiology

  • Spontaneous tumor arising from genetic mutations, and may progress to high grade tumors with increasing mutations. May arise from fibrillary or protoplasmic astrocytes. Typically single, not known to spread outside the CNS.

Predisposing factors

General
  • None known.

Pathophysiology

  • A primary tumor of brain, arising from astrocytes, a non-myelinating glial cell. May also arise in the spinal cord and optic nerve.
  • A tumor of astrocytes, neuroectodermal in origin. Signs depend on location and rate of progression, plus contribution of inflammatory component. Mass effect of tumor directly, plus indirect effects of edema, necrosis and vascular complications may add to clinical signs. Initial compensation by altered blood flow and CSF balance, but eventually further increase in mass effect causes marked rise in intracranial pressure. Tumors obstructing CSF flow compound the problems. Disruption of blood brain barrier may occur in some tumors, with associated edema, effectively increasing the size of the mass.

Timecourse

  • Variable. Progression can be slow (months/1-2 years), since neural tissue may accommodate slow expansion. Other tumors progress rapidly (days) from onset of first signs. Usual progression is in the range of weeks to months. Necrosis and edema, as well as location determine rate of development of signs.

Epidemiology

  • Meningiomas are most common tumor reported in most studies although some studies list astrocytomas as the most common tumor type occurring in the brain.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Synder J M, Shofer F S, Van Winkle T J & Massicotte C (2006) Canine intracranial primary neoplasia: 173 cases (1986-2003). J Vet Intern Med 20 (3), 669-675 PubMed.
  • Vernau K M, Higgins R J, Bollen A W, Jimenez D F, Anderson J V, Koblik P D & LeCouteur R A (2001) Primary Canine and Feline Nervous System Tumors: Intraoperative Diagnosis Using the Smear technique. Vet Pathol 38, 47-57 PubMed.
  • Bagley R S, Gavin P R, Moore M P, Silver G M, Harrington M L & Connors R L (1999) Clinical Signs Associated with Brain Tumors in Dogs: 97 Cases (1992-1997). J Am Vet Med Assoc 215, 818-819 PubMed.
  • Koblik P D, LeCouteur R A, Higgins R J, Bollen A W, Vernau K M, Kortz G D & Ilkiw J E (1999) CT-Guided Brain Biopsy using a Modified Pelorus Mark III Stereotactic System: Experience with 50 DogsVet Radiol Ultrasound 40, 434-440 PubMed.
  • Thomas W B, Wheeler S J, Kramer R & Kornegay J N (1996) Magnetic Resonance Imaging Features of Primary Brain Tumors in Dogs. Vet Radiol 37 (1), 20-27 VetMedResource.

Other sources of information

  • Koestne A & Higgins R J (2002)Tumours of the nervous system.In: Meuten D J (ed.)Tumours in Domestic Animals, 4th edn, pp 697738. Iowa State Press, Iowa.
  • LeCouteur R A (2001)Tumors of the nervous system.In: Withrow S J, MacEwen E G (ed)Small Animal Clinical Oncology, 3rd edn, pp 500-531. W B Saunders, Philadelphia.
  • Morrison W B (1998)Cancer affecting the nervous system.Chapter 42 In:Cancer in Dogs and Cats Medical and Surgical Managementpp 655-665. Williams & Wilkins. London.
  • Summers B A, Cummings J F & deLahunta A (1995)Tumours of the central nervous system.In:Veterinary Neuropathology, pp 362370. MosbyYear Book, St Louis.
  • Vite C H (2005)Neoplasia of the Nervous System.In:Braunds Clinical Neurology in Small Animals: Localization, Diagnosis and Treatment.International Veterinary Information Service [online}. Available at:http://www.ivis.org/advances/Vite/braund26/IVIS.pdf.


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