Meningiomas in Dogs

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Meningiomas in Dogs

By: Dr. John McDonnell

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Section: Overview

Meningiomas are a common, well-defined brain tumor arising from the meninges, which is the covering surrounding the brain. Meningiomas usually occur in older dogs greater than 8 years old. There does not seem to be a sex predisposition for brain tumors.

Meningiomas are very slow growing tumors that compress the brain rather than invade brain tissue. Because they are slow growing, the brain may be able to compensate or adjust to their presence.

Symptoms most often associated with brain tumors are personality changes such as not wanting to play, altered appetite, sleeping and hiding; seizures; weakness in the limbs; uncoordinated walking; or abnormal eye/facial symmetry. Meningiomas may be quite large before they cause symptoms. Symptoms may be caused by swelling and edema, which is a build-up of fluid around the tumor.

If a meningioma grows very slowly, its symptoms may appear so gradually that they are overlooked for a long time.

Diagnosis

Your veterinarian may ask the general history of your pets' medical past as well as the first appearance of symptoms and will perform a complete physical to check for general signs of health.

A neurologic examination may be included to characterize and localize the area of the brain being affected.

Laboratory tests may be done to check the general health of the other systems in the body such as the bone marrow, liver and kidney.

Laboratory tests are part of a pre-anesthetic screening needed prior to further brain imaging.

Depending on your veterinarian's access to some of the advanced diagnostic tools necessary to diagnose meningiomas, your pet may be referred to a specialist such as a neurologist, internist, or oncologist.

Brain imaging consisting of either a CT (computed tomography) scan or an MRI (magnetic resonance imaging) to look at the brain. Both techniques require anesthesia because the pet must lie very still for 30 to 60 minutes. Although MRI is a better imaging method than CT, availability and cost may limit its use in many cases.

Treatment

Treatment for a canine meningioma depends on a number of factors. Among these are the type, location, and size of the tumor as well as your pet's age and general health.

Your veterinarian develops a treatment plan to fit each patient's needs and other factors. Some important questions to ask your veterinarian include what treatments are available and how effective are the treatments.

Meningiomas are treated with surgery, radiation therapy and chemotherapy. Several methods may be used in combination or individually. Before treatment begins, most dogs are given steroids to relieve edema. They may also be given anticonvulsant medicine to prevent or control seizures.

Surgery is the usual treatment for most meningiomas. To remove a brain tumor, a neurosurgeon performs a craniotomy, or makes an opening in the skull.

Radiation therapy or radiotherapy uses high-powered rays to damage cancer cells to stop them from growing. It is best used to destroy microscopic tumors following surgery. Radiotherapy can be used when surgery is not possible. Your pet may be heavily sedated or anesthetized for each radiotherapy session.

Chemotherapy, or administration of drugs that are used to kill cancer cells, may be recommended.

Side effects occur with any treatment recommended for brain tumors in your pet. The best person to ask regarding side effects for suggested or considered treatment is your veterinarian that is directing treatment.

The treatment of cancers in general are often related in terms of prognosis. It is important to remember that statistics are based on averages from a large number of patients. They cannot be used to predict what will happen to a certain patient because no two cancer patients are alike. The doctor who takes care of the patient and knows the pet's medical history is in the best position to discuss your pet's prognosis. It is important to know that not even your veterinarian can tell exactly what will happen with your pet.

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