Canine Glioma

by Betty Lewis
    Short-nosed breeds such as boxers have a higher incidence of glioma.

    Short-nosed breeds such as boxers have a higher incidence of glioma.

    Photodisc/Photodisc/Getty Images

    It's not uncommon for an older dog to develop a brain tumor; increasingly, younger dogs are found to be developing them, too. Tumors vary in their types, malignancy levels and treatment options. Glioma, the second most common type of brain tumor in dogs, is an area of intense research.

    A brain tumor is a mass in the brain; a tumor developing from the supportive tissue of the brain, called a glioma, is common in people and dogs. Gliomas range from low-grade and slow-growing tumors to poorly differentiated high-grade malignant tumors referred to as glioblastoma multiformes. For reasons still unknown, almost half of all gliomas occur in brachycephalic or "squash-nosed" breeds such as Boston terriers, bulldogs and boxers.

    Gliomas can develop in different areas of the brain. For example, one type of glioma, oligodendroglioma, usually occurs in the frontal lobe, while the lower-grade astrocytoma tends to develop in the temporal lobe. Symptoms depend on where the mass is located and include circling, behavioral changes, head tilting, unsteady walking, seizures, and increased or decreased appetite and thirst.

    If your pup is older than 5 years and has shown any symptoms or other signs he's being affected by something neurologically based, the vet will likely consider a tumor as one of the potential culprits. A thorough physical and neurological exam is necessary to identify other health issues and focus the neurological symptoms to one part of the dog's brain. Blood work will rule out other potential illness and evaluate his anesthetic risk. Radiographs will confirm or deny the spread of any tumors to other parts of the dog's body. A CT or MRI of the brain, done under general anesthesia, will identify fluid buildup, bleeding or changes in tissue, and will help identify the type and grade of tumor. Only biopsy can confirm this type of tumor. A sample identifies the type of tumor and grades the malignancy.

    If the tumor is surgically accessible, removing the tumor is the preferred treatment. Gliomas can be difficult to surgically remove because they're often near brain tissue that's vulnerable to damage during surgery. Radiation, which shrinks the tumor and slows its growth, is the most common treatment for glioma. Chemotherapy and palliative care to provide comfort are applied as necessary. The prognosis for a dog with glioma varies depending on tumor type, location and size, and how severe the symptoms are.

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    About the Author

    Betty Lewis is a writer and editor specializing in pet care, animals, careers and emergency management. She previously ran an animal shelter, where she also served as a kennel attendant and dog trainer. Lewis holds a bachelor's degree in journalism, an M.B.A. and a master's degree in professional studies.

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