Microgliomatosis

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

Microgliomatosis (Gliomatosis cerebri) is a rare brain tumor of dogs characterized by diffuse and widespread infiltration of the central nervous system by neoplastic gliomas of neuroepithelial origin[2].

These tumors can be difficult to distinguish from astrocytomas but are usually distinguished by more widespread neuraxial involvement and relative preservation of brain architecture[1].

A breed predispositon has been noted in the Poodle, Flat-coated Retriever[3], St. Bernard[4] and German Shepherd[5].

Two forms are recognized:

  • Type I - classic form characterized by diffuse cerebral infiltration without the formation of a discrete, grossly visible mass.
  • Type II - gliomatosis characterized by diffuse infiltrate accompanied by a mass lesion[6]

Affected dogs are usually middle-aged (3 - 9 years) male dogs which usually present with central neurological disease symptoms such as mental depression, nonambulatory tetraparesis, hypermetria, head tilt, ataxia and circling[7].

A presumptive diagnosis can be established based on CT or MRI imaging[8], but definitive diagnosis requires histological examination of biopsied brain tissues, often taken postmortem.

A differential diagnosis would include lymphoma[9], oligodendroglioma, primitive neuroectodermal tumor, meningioma, astrocytoma and ependymoma.

Although palliative treatment with dexamethasone or oral prednisolone may relieve many of the physical symptoms, treatment usually requires surgical debulking and radiation therapy.

The prognosis is many cases is guarded due to the infiltrative nature of this neoplasia and rapid deterioration of clinical symptoms[10].

References

  1. 1.0 1.1 Porter B et al (2003) Gliomatosis cerebri in six dogs. Vet Pathol 40(1):97-102
  2. Willard MD & Delahunta A (1982) Microgliomatosis in a Schnauzer dog. Cornell Vet 72(2):211-219
  3. Gruber A et al (2006) Gliomatosis cerebri in a dog. J Vet Med A Physiol Pathol Clin Med 53(8):435-438
  4. Fukuoka H et al (2012) Gliomatosis cerebelli in a Saint Bernard dog. J Comp Pathol 147(1):37-41
  5. Plattner BL et al (2012) Gliomatosis cerebri in two dogs. J Am Anim Hosp Assoc 48(5):359-365
  6. Koestner A et al (1999) Histological Classification of Tumors of the Nervous System of Domestic Animals, 2nd series, vol. V, pp. 22–25. Armed Forces Institute of Pathology, Washington, DC
  7. Fankhauser R & Frauchiger E (1967) Microgliomatosis in dogs. Dtsch Tierarztl Wochenschr 74(6):142-146
  8. Martin-Vaquero P et al (2012) MRI features of gliomatosis cerebri in a dog. Vet Radiol Ultrasound 53(2):189-192
  9. Vandevelde M et al (1981) Immunohistological studies on primary reticulosis of the canine brain. Vet Pathol 18(5):577-588
  10. Galán A et al (2010) Oligodendroglial gliomatosis cerebri in a poodle. Vet Comp Oncol 8(4):254-262