What is Adrenal Gland Cancer (Pheochromocytoma)?
Your dog’s adrenal gland has two unique areas, which are the inner medulla and the outer cortex. The cortex has several layers that create and distribute three chemicals, androgens, glucocorticoids, and mineralocorticoids (aldosterone). What makes this type of cancer even more dangerous is the rate of speed with which it spreads to other organs. This happens due to the fact that the adrenal gland has a direct route through lymph nodes for distributing hormones, and cancer cells are able to be distributed right along with them. The cause of pheochromocytoma is not known yet, although some veterinary medical professionals believe that exposure to toxins or other chemicals may be a contributing factor.
Adrenal gland cancer (pheochromocytoma), which are endocrine tumors that come from the chromaffin (neuroendocrine) cells in the adrenal gland, are not common in dogs. Pheochromocytoma can cause an increase of hormones, which include epinephrine, aldosterone, and cortisol. These hormones cause symptoms that are like those that happen when your dog is stressed, only these can happen at any time, no matter whether your dog is stressed or not. Just like many other cancers, pheochromocytoma is most common in older dogs, and the average age of those with pheochromocytoma is about 10 years old.
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Symptoms of Adrenal Gland Cancer (Pheochromocytoma) in Dogs
The symptoms of pheochromocytoma may not be noticeable in many dogs, because they are mild, intermittent, and can be mistaken for many other diseases and disorders. Some of the most common are diabetes, renal disease, hyperadrenocorticism, and hepatic disorders. Clinical symptoms that are most often noticed are:
- Abdominal distention
- Acute blindness
- Dry skin
- Excessive thirst and urination
- Loss of hair
- Lumps on neck and back from calcium deposits
- Nosebleeds (epistaxis)
- Weight loss
Causes of Adrenal Gland Cancer (Pheochromocytoma) in Dogs
As with many cancers, studies are underway to try and unravel the mystery of this disease, which can be so detrimental to the health of humans and animals alike. Presently, the cause of pheochromocytoma is not known, although some experts believe it has something to do with exposure to toxins or chemicals.
Diagnosis of Adrenal Gland Cancer (Pheochromocytoma) in Dogs
Your veterinarian will do a physical examination of your dog that includes body temperature, weight, height, heart rate, respirations, blood pressure, and reflexes. He will do some neurological tests to see if your dog’s sensory and motor skills are normal, as well as balance, coordination, and cognition. Laboratory tests, such as complete blood count, blood chemistry profile, glucose levels, urinalysis, and fecal examination.
Your dog’s medical history is usually needed to inform the veterinarian of any illnesses or injuries your dog has had, and if his immunizations are up to date. Be sure to let him know if there has been any strange behavior or change in appetite. A fine needle aspiration will be done if it is possible to remove cells from the tumor for analysis. This will let the veterinarian know if the tumor is cancerous. An MRI, ultrasound, CT scan, and x-rays will be done to determine the areas affected by the tumor and to see if it has spread.
Treatment of Adrenal Gland Cancer (Pheochromocytoma) in Dogs
Since pheochromocytomas usually occur with other medical disorders, the veterinarian will want to treat the one that is the most serious first. Some of these are pulmonary edema, heart attack, cerebral hemorrhage, extreme increase in blood pressure, and heart failure. Treatment for pheochromocytomas includes removal of the adrenal gland and nearby lymph nodes. If it cannot be removed with surgery because of other illness or age, medications such as Lysodren can be used. However, this drug may also have serious side effects, so the veterinarian may choose to keep your dog under observation for the first 24 hours. The surgery to remove the adrenal gland is complex and has many possible complications, such as severe spikes in blood pressure and pulmonary embolism. Some other critical side effects of surgery may include electrolyte imbalances, hemorrhage, and pancreatitis.
The best treatment for any kind of tumor is surgical removal, but sometimes that is not an option. Sometimes, it may be necessary to remove the gland as well as the tumor, in which case your dog will need medication indefinitely to regulate his hormones. In some cases, the tumor may be unable to be removed, such as when it has integrated itself into a vital organ or if it has already metastasized. In these cases, chemotherapy may be suggested if your dog is in relatively good health, but these tumors are hard to treat with chemotherapy alone.
If the tumor is small and has not spread, the veterinarian may decide to use radiofrequency ablation (RFA) to kill the cancer cells. This procedure is done by sending a current of high temperature through a tiny needle into the tumor, which has been very successful in the past, and is less invasive than surgery.
Recovery of Adrenal Gland Cancer (Pheochromocytoma) in Dogs
If your veterinarian is able to remove the entire tumor without damaging the endocrine glands, the chances of your dog’s survival is excellent although there is a chance that the tumors may recur. If you and the veterinarian are able to catch it early enough, another treatment can virtually eliminate the chances of a recurrence. Be sure to follow up with your veterinarian regularly and contact him if there are signs of the tumor returning.
Adrenal Gland Cancer (Pheochromocytoma) Questions and Advice from Veterinary Professionals
I was told by a veterinary internist that a pheochromocytoma may be benign. According to this website, you are telling me that it is cancer and will metastasize. Any other current treatments other than surgery? How do you know for sure there was metastasis?
Pheochromocytoma are usually benign, but may be locally invasive and in some cases may metastasise to the liver, lungs and lymph nodes. The treatment of choice is surgical removal, but the overall prognosis is guarded; other treatment options are usually centered around stabilisation prior to surgery. Regards Dr Callum Turner DVM
Hey everyone! I just found out today through biopsy that my 12.5 year old shih tzu was diagnosed with pheochromocytoma.
About 3 weeks ago, he had his Right adrenal gland removed. The perioperative period was a little daunting but they said he did ok. THe only issue was low blood sugar and appetite but he bounced back the 2nd day post op.
Prior to this, my dog has been having MILDLY ELEVATED LIVER ENZYMES for about a year and a half. The vets wanted to recheck it in a month after starting him on Denamarin. Still high. This went on for months. THey kept telling me its nonspecific and nothing to worry about. We also ran a bile acid test to see if the liver was functioning. This was normal.
WHile I agree that liver enzymes being slightly elevated (especially for months to years) may seem non-specific and not something to be concerned about, they are still elevated and out of normal range. WHen ALT/AST enzymes are elevated for periods of time for no good reason, I do not believe that it is just a fluke. I am a critical care nurse and from taking advanced physiology and pathophysiology courses in graduate school, I learned that elevated enzymes means some type of damage. Yes it could be the food or other random etiology but I changed my dog's diet from kibble to FROZEN RAW or freeze-dried RAW and I was certain that this would help his liver values. Kibble is horrible and I've watched so many documentaries.
Nonetheless, I chose to chase it. Yes, it's mildly elevated. No, the Denamarin wasn't helping. Yes, the liver bile acid test was normal but I am not waiting until values become extremely abnormal before intervening. In medicine, there is a fine line between waiting and acting. I am GRATEFUL I ACTED. WHAT IS DAMAGING my dog's liver????
I took him for an ultrasound of the abdomen on my own free will. The vets said this was an option but were not pushing me to do it. He was diagnosed with Hepatic vacuolar hepatopathy which is another non-specific diagnosis. However, it is known that over secretion of hormones from the adrenal gland can cause this and subsequently cause damage to liver cells by storing glycogen on the surface of the liver.
My dog was exhibiting atypical cushings symptoms as well; this also supported the premise that there was something wrong with his adrenal gland.
Well, they found a nodule on his R adrenal gland.
The gold standard was to surgically remove it. As you all were, I was nervous to have my dog undergo surgery.
Anesthesia is scary and the perioperative phase even scarier. I was scared he would form blood clots, be in severe pain, or have deadly arrhythmias (heart rhythm disorders) and even electrolyte imbalances. NO prophylactic anti-coagulants for dogs apparently; in humans we administer heparin a couple days after surgeries.
However, my dog is resting and is his happy joyful self three weeks later. I followed my surgeons instructions for home care to the T.
If you can help it do the surgery. I made sure to optimize my dog's health prior. I walked him 3x's a day, fed him NO kibble only RAW frozen (Primal pet from pet supplies plus) and gave him supplements/vitamins. I also give him probiotics in his water because he was sent home with 4 weeks worth of antibiotics. I had to taper Prednisone (a steroid) until his left adrenal gland would function and compensate.
It was a small tumor and it did not invade the vena cava (my biggest worry). Since it was on the R side, it was a little more risky because it is further back than the left one which means more manipulation. It was done open abdomen instead of laparoscopically given the location and depth of the tumor.
I will follow up and see how I can monitor for any metastasis. He said it is HIGHLY unlikely but is estimated at 15% per literature. However, he has never seen this in his practice.
He also mentioned recurrence? But, I am not sure what he meant by that because he took out the entire R adrenal gland.
Nonetheless, point is: CHASE YOUR DOUBTS!!!! Shih tzu's also typically have a longer life span (~16-18 years) which is why I decided even more that this was the right decision. AT the time of agreeing to do the adrenalectomy, I did not know yet if it was malignant or benign and my internal med vet said there is no way of knowing unless the gland is removed and sent for biopsy. SO... I went for it, said a lot of prayers and prepped my dog in the best way I knew how.
You are your pet's ADVOCATE. If something doesn't feel right, it probably isn't. I am lucky that I have medical/nursing background to support my actions.
I hope I helped you guys with any questions. Sorry if there are typos, I just came from working a 13 hour shift. I will try to check back on this website to answer questions.
- Xtine RN, BSN, CCRN
My dog passed away this last July 2017 . He was diagnosed with Pheochromacytoma and early stage kidney disease in May of 2016. Fearing the complications of surgery, we opted to try Radiation Sterotatic treatment. Which is treating the tumor with high radiation . This treatment has no proven track record with this type of cancer. We got mixed results. After a year his tumor only increased 1 cm . However, the tumor was functional meaning, my dog had to stay on the same high dosage of blood pressure meds to counter act the hormonal release. We thought the tumor would shrink and his blood pressure would decline over the months but didnt. The last two months his blood pressure remain stable and normal with his meds. But his heart rate increased from average of 100bpm to 130 bpm. In combination with his kidney disease which we had stabilized his appetite decreased. The last week of his life he stopped eating all together. His blood pressure could no longer be controlled with medication. If I had to do it over again, I would have opted for the surgery. Although the tumor may be considered benign, the functional nature of the hormone release is what causes damage from the increased blood pressure.
Just got the news that our 9 yo dog may have this. I am praying surgery is an option although ultrasound showed a decent sized mass. Never did I expect to hear this when I took him in due to increasing lethargy from last week. Last week he went in for an ear infection! Today ... this ! Shocked. Feeling bad that I must have missed signs but vet explained there are episodic & easily missed. All I know is my doggy is totally different from last Saturday to today! All I am reading is exactly my dog. So sad but hopeful. Your post was very helpful. I will opt for surgery if an option based on your comments.
Hello Jaz. I am so sorry for your loss. You must be heartbroken. It is always so difficult to know what to do for the best. Our vet thinks our 12 year old greyhound has it. She has recommended a CT scan but we are worried due to the anaesthesia his very high blood pressure. Do you mind me asking how old your dog was? Take care. X
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My dog is 12 1/2 years old. He was diagnosed with the pheochromocytoma tumor. No mention of metastasis. Dr. wants to know if I want chemotherapy done. I can't find any information on this. How do I know if he needs it or it works? He had an adrenalectomy.
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