Glioma

From Dog
Gliomatosis cerebri in a dog, showing neoplastic infiltration in the right hemisphere[1]

Glioma are a common neoplasms of neural tissue that can caused brain tumours and spinal cord tumors in dogs.

Gliomas can range in malignancy from low grade and slow growing, to high grade, poorly differentiated malignant tumors (known as glioblastoma multiforme)[2].

These tumors arise from the supporting cells of the brain (glial cells) and include:

Tumor Region affected Frequency
Astrocytoma[3] Piriform area, convexity of cerebral hemispheres, thalamus, hypothalamus Common
Oligodendroglioma Cerebral hemispheres Common
Glioblastoma[4] Piriform area, convexity of cerebral hemispheres, thalamus, hypothalamus Uncommon
Microgliomatosis (Gliomatosis cerebria)[5] Periventricular areas, especially in cerebral hemispheres Common
Spongioblastoma Variable, eg, ependymal surfaces, cerebellum, optic nerve and tracts Rare
Medulloblastoma Cerebellum Uncommon

They are common in certain breeds of dog such as the Boxer, Boston Terrier, French Bulldog and English bulldog.

Clinically affected dogs are usually middle-aged but can occur from 6 months of age[6] and symptoms may include seizures, cranial nerve deficits, circling, ataxia and varying degrees of hemiparesis[7].

A presumptive diagnosis can be made on presenting clinical signs and MRI or CT imaging studies which usually reveal a localized mass within the cerebrum or cerebellum[8].

Definitive diagnosis requires histological examination of tissue biopsies, often obtained during surgical extirpation.

A differential diagnosis would include lymphoma, other brain tumors and cerebrovascular accidents[9].

The glioblastoma multiforme are among the most aggressive of all malignancies in dogs and are difficult to treat and generally considered incurable with singular or multimodal therapies[10].

Palliative therapy with parenteral dexamethasone or oral prednisolone may temporarily abate clinical symptoms but curative therapy involves surgical debulking (if possible), followed by chemotherapy (such as lomustine) and radiation therapy[11].

Prognosis is variable depending on the type of glioma involved and duration of growth, but canine intra-axial gliomas is generally poor[12].

References

  1. Porter B et al (2003) Gliomatosis cerebri in six dogs. Vet Pathol 40(1):97-102
  2. Garcia PA et al (2011) Non-thermal irreversible electroporation (N-TIRE) and adjuvant fractionated radiotherapeutic multimodal therapy for intracranial malignant glioma in a canine patient. Technol Cancer Res Treat 10(1):73-83
  3. Stoica G et al (2011) Canine astrocytic tumors: a comparative review. Vet Pathol 48(1):266-275
  4. Röthlisberger A et al (2012) Suspected primary glioblastoma multiforme in the canine spinal cord. J Small Anim Pract 53(10):604-607
  5. Reitman ZJ et al (2010) IDH1 and IDH2 hotspot mutations are not found in canine glioma. Int J Cancer 127(1):245-246
  6. Wong M et al (2011) Intracranial anaplastic astrocytoma in a 19-week-old boxer dog. J Small Anim Pract 52(6):325-328
  7. Schwartz M et al (2011) Canine intracranial neoplasia: clinical risk factors for development of epileptic seizures. J Small Anim Pract 52(12):632-637
  8. Koch MW et al (2011) Multifocal oligodendroglioma in three dogs. J Am Anim Hosp Assoc 47(5):77-85
  9. Cervera V et al (2011) Comparative magnetic resonance imaging findings between gliomas and presumed cerebrovascular accidents in dogs. Vet Radiol Ultrasound 52(1):33-40
  10. Stupp, R et al (2005) Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med 352:987-996
  11. Hasegawa D et al (2012) Long-term survival in a dog with anaplastic oligodendroglioma treated with radiation therapy and CCNU. J Vet Med Sci 74(11):1517-1521
  12. Dickinson PJ et al (2010) Canine spontaneous glioma: a translational model system for convection-enhanced delivery. Neuro Oncol 12(9):928-940