For the past two years, staff at Perth Veterinary Specialists have been working to investigate and treat a complex medical condition affecting Torpy, an 11 year old female Alaskan Malamute dog. Torpy was referred to the Veterinary Medicine Specialists (VMS) in March 2010 to investigate symptoms of excessive drinking and urinating. Her owner also described that Torpy would frequently wake in the middle of the night and want food.
The initial work‐up by VMS involved blood and urine testing, and an abdominal ultrasound. The ultrasound, performed by radiologists at the Veterinary Imaging Centre, found a mass affecting the right adrenal gland. The adrenal glands are located near the kidneys, and their role is to produce hormones including adrenalin and steroid hormones that have a wide range of effects on most other organs in the body, including the metabolism. Each adrenal gland is normally about 2cm long and 7mm wide; however despite their small size, when things go wrong, normal metabolism can be severely thrown off balance.
Ultrasound is a good first step to examine the abdomen, but in a large dog, it is difficult to reach around the liver and up under the spine, where the adrenal glands live. A CT scan is a better test to look at adrenal gland masses. In Torpy’s case, the CT showed the right adrenal gland was 4‐5 times its normal size, most likely due to cancer. The CT scan confirmed that the cancer had probably not spread into the nearby tissues. Further testing showed that Torpy’s blood pressure varied wildly (sometimes very high, sometimes quite low), which was probably the cause of her weight loss, panting, anxiety, restlessness, depression and in‐coordination. These results suggested that the tumour was growing from the inner portion of the adrenal gland, the adrenal medulla. One of the substances the adrenal medulla produces is adrenaline which affects blood pressure via altering the hearts output, explaining Torpy’s multiple problems.
Surgical removal of adrenal tumours is the treatment of choice, however prior to surgery Torpy had her blood pressure controlled through medical management. Torpy then underwent surgery at Perth Animal Surgery. The right adrenal mass was removed. Histopathological analysis of the adrenal tissue confirmed the diagnosis of pheochromocytoma, a rare type of endrocrine tumour typically causing vague clinical signs affecting older dogs.
Once Torpy had recovered from the surgery, she was sent home with a plan to return for regular checks of her blood pressure as well as repeat diagnostic imaging procedures every few months in order to monitor for any recurrence or progression of the cancer.
In April 2011, a whole year after her surgery, another CT scan showed a new mass in the region of the previously resected adrenal gland. It was also noted that the nearby lymph nodes were enlarged, which can often be a sign that the cancer may have spread. Unfortunately, any malignant cancer can return after surgery; the more aggressive the cancer, the more likely it will come back in future. A second surgery was undertaken and the new mass was resected. Torpy again recovered really well and in August 2011, a repeat CT scan showed no evidence of recurrence in the liver. However by January 2012, nearly 2 years after the initial surgery, Torpy was again drinking excessively and a CT scan showed several liver nodules indicative of metastatic cancer spread. At this time, an abdominal ultrasound was also performed, and further samples of liver tissue were collected confirming that the cancer had spread.
Dr Amanda Paul from VMS says that pheochromocytoma shows a spectrum of malignancy and can metastasize widely, “It can cause sudden death if it invades the vena cava, but otherwise survival times can be greater than two years”. Dr Paul says that whilst Torpy won’t be having any further surgery, she remains happy in herself and will be managed with medication. Imaging specialist Dr Zoe Lenard says it’s been a remarkable journey for Torpy, “Torpy has avoided the pitfalls of complications such as haemorrhage so far. We’ve been monitoring her condition for two years and she’s had two big surgeries in that time, but each one went really smoothly and she recovered well. The most important thing to me is that she has bounced back after each one and led a happy, healthy life for the last two years. Without this treatment, she most certainly would have died shortly after her initial diagnosis“.
For Torpy’s owner Lois, the last two years of treatment has been full of highs and lows, as Lois explains, “This journey has been a roller‐coaster, from the realization that Torpy had an aggressive tumour, to the fantastic recovery and the year of clear CT results, then to the sad reality that the tumour had re‐grown and going through another surgery with an absolutely amazing recovery and then to the discovery of metastases.
I hope that Torpy will be with me for more years, but I know that whatever happens she was in the best and most capable hands I could find. She is still getting the best treatment I can get her and boy she loves life. She has always been strong and happy, loud and opinionated and a mummy’s girl – and we’ll be together as long as we can”.
“Torpy” initial CT study
This image is a thick slice through the dogs abdomen with the dog’s head located above the top of the image. The liver and right kidney are labelled. The right adrenal gland mass (A) is visible next to the right kidney and closely associated with the aorta. The CT scan shows nicely how the adrenal mass is discrete and does not invade into the adjacent structures like blood vessels. This lesion is more easily seen on CT than ultrasound.