BRAIN TUMORS IN DOGS AND CATS

Brain tumors are a relatively common neurological problem in dogs and cats and typically affect older pets.

Certain breeds are over-represented including the Boxer dog, Golden Retriever and Boston Terrier.
Clinical signs depend on the location of the tumor, but may include seizures, behavior changes, compulsive circling, weakness, wobbliness, blindness, and balance problems.

Types of Brain Tumors

Brain tumors may be thought of as primary brain tumors and secondary brain tumors.  Primary brain tumors arise from cells that make up the brain and it’s lining.  Secondary brain tumors arise elsewhere and spread to the brain (metastasis).

Primary brain tumors in dogs and cats may include meningiomas, glioma, choroid plexus tumors, ependymoma, pituitary tumors and others.

Meningiomas are the most common type of primary brain tumor in dogs and cats.  They arise from the meninges (covering of the brain).  They are more common in long-nosed breeds of dogs, such as the Golden retriever.  They tend to be slow-growing and compress the brain from the ‘outside’ in.

Gliomas arise from the supporting cells of the brain (glial cells) and include astrocytomas and oligodendrogliomas. They are more common in short-nosed breeds of dogs, including the Boxer and Boston terrier. They tend to grow on the ‘inside’ of the brain.

Diagnosis of Brain Tumors

Clinical signs depend on the location of the tumor, but may include seizures, behavior changes, compulsive circling, weakness, wobbliness, blindness, and balance problems.  There are other neurological diseases that can cause identical clinical signs, and therefore further tests are warranted.  A CT scan may show some types of brain tumors, but MRI is considered the best imaging modality when a brain tumor is suspected.  A biopsy is necessary for a definitive diagnosis.

Large mass in the brain of a cat. Surgery was performed to remove the tumor which was a meningioma.

MRI of the brain of a dog showing a glioma.

High-field MRI of the brain showing a pituitary tumor (arrow) at the base of the brain.

Treatment of Brain Tumors

Types of brain tumors depends on the size, location and suspected type of tumor.  Treatment options may include surgery, radiation therapy, chemotherapy, or palliative medications.