Pituitary Tumors In Dogs
The pituitary gland is a small organ with a big job. Located at the base of a dog’s brain, this pea-sized gland is a critical part of the endocrine system, producing hormones that help control other organs and body functions. Fortunately, tumors that can prevent the pituitary gland from functioning properly are very rare. Fewer than 1 in 100 dogs will develop a pituitary tumor, and most are not cancerous. Even a benign canine pituitary tumor can impact quality of life, however. In addition to affecting hormone production, a growing tumor can press against parts of the brain and/or optic nerves. Thus, signs that a dog may have a pituitary tumor can vary. They can include trouble with motor skills (such as difficulty walking), onset or worsening of diabetes, or vision loss, among others. The good news is that radiation, commonly used to treat pituitary tumors, is typically quite effective when the tumor is caught in time. In some cases, symptoms will even be completely resolved after a few months.
Types of Pituitary Tumors in Dogs
Although dogs rarely get pituitary tumors, those that do are typically older (10 or older). No particular breed is more susceptible; nor does a dog’s sex seem to be a factor. There are also different types of pituitary tumors:
Adenoma: A pituitary adenoma in dogs is the most common type and they are benign. That means they are not cancerous and will not metastasize (spread), but they will grow locally. Larger adenomas, called macroadenomas, are most likely to impact the brain or nearby optic nerves.
Adenocarcinoma: If a pituitary tumor is found to be malignant, it is called an adenocarcinoma. They are exceedingly rare. Early detection is important because malignant cells can spread to the lungs, lymph nodes and the liver.
Clinical Signs and Symptoms
- Hormone-related — Increased thirst, more frequent urination and a noticeably bigger appetite can be signs of a medical condition that needs attention, including diabetes or Cushing’s disease. Both diseases are related to the endocrine system, which is controlled in part by the pituitary gland. Thus, these diseases can stem from pituitary tumors that disrupt hormone production. They have other causes as well, however, so it doesn’t necessarily mean a dog has a pituitary tumor if stricken by one of these diseases.
Diabetes is associated with a deficiency in insulin, a hormone secreted by the pancreas. Insulin helps regulate blood sugar. An insulin deficiency may cause an increase in thirst and urination. A diabetic dog also may have a ravenous appetite and yet still may experience weight loss.
Cushing’s disease, on the other hand, is related to the excess production of another hormone, cortisol. The result is a condition called hyperadrenocorticism. Changes in the dog’s coat, an increase in blood pressure and the presence of a pot belly are additional symptoms of Cushing’s disease.
- Neurological — There are also a number of neurological signs of a pituitary tumor in dogs. In addition to the increased thirst/urination/hunger, these could include seizures, memory loss or being mentally dull or foggy. Ataxia, a loss of control of body movements, also may present as difficulty walking or a dog circling in one direction.
- Blindness — If a pituitary tumor is large enough to press on optic nerves, a dog could experience blindness. Sometimes this is temporary if the tumor can be shrunk. Notably, blind dogs can do well if furniture is kept in place.
Diagnosing Pituitary Tumors
A veterinarian will rely on a number of diagnostic procedures that will help determine whether a dog has a pituitary tumor and what the next steps will be:
- Bloodwork, urinalysis and checking blood glucose levels are standard.
- Although most pituitary tumors are benign, chest X-rays may be taken if malignancy is suspected or to rule out metastasis to the lungs. Similarly, an abdominal ultrasound can determine whether malignant cells have spread to other places, including the liver.
- An MRI of the brain could be recommended to help determine the exact location of a tumor, as well as its size.
Treatment Options and Prognosis for Pituitary Tumors
Radiation is typically the treatment of choice for a pituitary gland tumor in dogs. The goal of radiation is to shrink the tumor, alleviating the symptoms caused by its growth. Symptoms typically improve after about two months and may resolve completely. Vision may even return in cases in which blindness has occurred. Managing diabetes might be easier, and it’s possible a dog may no longer require insulin. Dogs typically do well after radiation for one to two-plus years. There are two primary types of radiation:
Conventionally fractionated radiation therapy (CFRT) typically consists of 16 to 18 treatments.
Stereotactic Radiation (SRS/SRT)
Stereotactic Radiation, an innovative treatment, usually requires just one to three treatments and can be used to fight pituitary tumors. This involves a radiation oncologist creating a plan that will damage the tumor as much as possible while excluding as much surrounding healthy tissue as possible from the radiation field. Another key benefit, especially for older dogs, is the lower number of treatments means fewer times being subjected to anesthesia. The PetCure Oncology team is experienced and highly qualified to provide stereotactic radiation therapy.
If a pet owner for any reason decides not to opt for radiation therapy, steroids can be prescribed to manage a dog’s neurologic symptoms and improve his or her quality of life. However, steroids may make diabetes and Cushings’ clinical signs worse, therefore it is imperative to consult with your veterinarian. Without treatment, a tumor will continue to grow and symptoms can worsen. Eventually, a dog with a pituitary tumor may lose its appetite and continue to lose weight. At that point, a pet owner must make decisions based on quality of life. However, this could be many months if the tumor is small.
Find a PetCure Oncology Location Near You
In the event your dog is diagnosed with a rare pituitary tumor, you should know the PetCure Oncology is here to provide the best care possible. We offer the most advanced and innovative treatment options and will support you and your dog through our clinical excellence, professionalism and compassionate care. Just like you, we want to prolong your dog’s quality of life for as long as possible.
To learn more about PetCure Oncology and our innovative treatment options, find a location near you today.