TUMORS OF THE CENTRAL NERVOUS SYSTEM

The neoplasms of the S.N.C. include brain tumors and those of the spinal cord, they are divided into primary (originating from the neuroectodermal, ectodermal and mesodermal tissue) and secondary (reaching the CNS through hematogenous diffusion or contiguity); with the exception of lymphoma, they rarely give distant metastases, rather they tend to spread within the nervous system itself through the cerebrospinal fluid.

Based on the histotype, it is possible to further classify them into:

A higher incidence is found in elderly subjects and in brachycephalic breeds, however, there are some typical forms of young dogs, including primary neuroectodermal tumors, neuroblastomas, ependymoblastomas and thoracolumbar medullary neoplasia of young dogs.

Clinical manifestations often have a slow and progressive onset and obviously depend on the site of the neoplastic lesion which can manifest itself because it has destroyed or compressed adjacent tissues, causing hemorrhages or obstructive hydrocephalus.

The clinical diagnosis, depending on the location, may be characterised by convulsive crises (frequent sign), lethargy, head pressing (pushing against the wall), ataxia, vestibular syndrome, facial paralysis, behavioural alterations, circulating locomotion (circling) , head rotation, hypermetry, paresis, paralysis, urinary / fecal incontinence.

In addition to the neurological examination, CT and MRI are essential for diagnosis; the cytological examination of the CSF is not useful except for metastatic tumors and lymphomas. Instead the cytological examination of samples taken from the tumor mass in the intraoperative phase is becoming more and more of a diagnostic tool, which can provide the surgeon with important information. Surgical removal represents the treatment option for non-infiltrating and accessible forms; radiotherapy is indicated either after surgery, in order to extend survival expectations, or alone for inoperable forms. Chemotherapy has a modest validity while steroids prove useful in reducing peritumoral edema. The prognosis is limited and life expectancy varies according to the type of cancer.