Brain Diseases of Geriatric Dogs and Cats

Brain tumors

Brain tumor incidence in dogs may approach 3% (one report states 14.5 per 100,000 dogs) and 2.2% in cats (one report says 3.5 in 100,000). Primary nervous system tumors originate from neuroectoderm, ectoderm, and/or mesoderm associated with the CNS or PNS. Secondary tumors affecting the nervous system may originate from structures around the CNS/PNS such as bone, or may result from metastasis of a primary tumor. Animals with brain tumors tend to be older dogs. In a retrospective review of 97 dogs with brain tumors, 95% of the affected dogs were 5 years or older at the time of diagnosis. The median age of dogs diagnosed with any brain tumor is 9.4 years (range 0.2 to 16 years); mean age for dogs with meningioma is 11.1 yrs (4-15 yr), for astrocytoma is 8.6 yr (4-15 yr), oligodendroglioma is 8.1 yr (2-14 yr), choroid plexus tumor 7.0 yrs (3-11 yr) and lymphoma is 7.4 yr (3-11 yr). The average age of dogs with secondary intracranial neoplasia is 9.6 yr. The most commonly affected breeds include Golden retrievers, mixed breeds, German Shepherds, Labrador retrievers, Boxers, Collies, Doberman pinschers, Schnauzers and Airedales. In cats, the overall mean age for brain tumors is 11.3 yrs (0.5-21.5 yrs). Cats with meningiomas are usually older (12.2 yrs) than cats with neuroepithelial tumors (8.2 yr). In a large feline study, there was no significant overall gender difference and the most common breed affected was the domestic shorthair. […]