What Is a Brain Tumor in a Dog? (PetMD by Chewy)

A tumor is an abnormal growth of body tissue. Tumors can occur in nearly any part of a dog’s body, including the brain. There are two broad categories of tumors:  benign (not cancer) and malignant (cancer). Brain tumors are classified as primary or secondary.

• Primary brain tumor: A primary brain tumor is one that originated in the brain or in one of the layers covering the brain, called the meninges.
• Secondary brain tumor:A secondary brain tumor is one that has spread to or invaded the brain after starting in another location. This can happen either by metastasis or by invasion.
  • Metastasis occurs when tumor cells break off from a primary tumor, travel through the body, and establish themselves elsewhere. Invasion occurs when a tumor extends into neighboring bodily tissues. (PetMD by Chewy)

Common Types of Brain Tumors in Dogs (SEVN)

Tumors that originate in the brain are called primary brain tumors. The two most common types of primary brain tumors in dogs are:

• Meningioma originating in the coverings of the brain
• Glioma originating in the support cells of the brain

Meningioma

Meningioma is the most common type of brain tumor seen in dogs. This tumor is technically considered benign in the sense that it does not spread to other parts of the body. However, if left untreated, it will cause ongoing neurologic deterioration.

• Treatment options generally include surgery and/or radiation therapy, which can maintain quality of life for a significantly extended period of time. Surgery typically offers the best outcome, as meningiomas are the most accessible tumors to remove. 

Glioma

Gliomas, on the other hand, can exhibit a more aggressive behavior and spread, or metastasize, to the spinal cord.

• These tumors usually cannot be removed, as they most often occur deep within brain tissue. However, radiation, and in some cases chemotherapy, are still options to maintain quality of life for a period of time. According to  Christine Senneca, Veterinary Neurologist at Southeast Veterinary Neurology (SEVN), “A lot of research is currently being done to find effective ways to treat this type of brain tumor.” 

“Brain tumors can also be a result of metastasis from a cancer that started in another part of the body,” adds Dr. Senneca. “These are called secondary brain tumors. An example of this is hemangiosarcoma, which is a type of cancer that most commonly develops on the liver or spleen, but can spread, or metastasize, to the brain.”  (SEVN)

What is a Canine Choroid Plexus Tumor? (Pet Cure Oncology)

A canine choroid plexus tumor, sometimes referred to as a papilloma, can be either benign or malignant.

• This type of brain cancer tends to begin in the brain’s ventricular system and can obstruct the drainage of cerebrospinal fluid. The tumors often look like small, red, ulcerative growths.
• Choroid plexus tumors expand over time and look like a round or cone-shaped protrusion.

What dogs are most susceptible to developing canine choroid plexus papilloma? 

• Canine choroid plexus papilloma is fairly rare and there is not enough data to indicate a higher incidence of this type of cancer in any particular breed.

What is a Peripheral Nerve Sheath Tumor? (Pet Cure Oncology)

Peripheral Nerve Sheath Tumors (NST’s), also known as Shwannoma, are tumors that originate in the myelin sheath, which surrounds peripheral nerves. The tumors are outside of the central nervous system so they are located on nerves outside of the brain and spinal cord, including:

• Neurofibrosarcomas (malignant nerve fiber tumors)
• Neurofibromas (nerve fiber tumors), and 
• Hemangiopericytoma (tumor of blood vessels and soft tissue)

What dogs are most susceptible to peripheral nerve sheath tumors?

• Peripheral nerve sheath tumors can occur in all dogs; no breed has been singled out as having a higher risk over others.

What is Canine Pituitary Adenoma? (Pet Cure Oncology)

Canine pituitary adenoma is a tumor of the pituitary gland, which is a small pea-sized gland located near the base of the brain.

• The pituitary gland is a tiny organ known for controlling hormones in the body that frequently affect the adrenal gland, thyroid gland and parathyroid gland.

What dogs are most susceptible to developing canine pituitary adenoma? 

• Certain breeds appear to be predisposed to developing canine pituitary adenoma including Miniature Poodles, Boxers, Boston Terriers, and Dachshunds. (Pet Cure Oncology)