When Geraldine noticed that Pooch’s left elbow had a small swelling bulging at the back, like a blister, she was not too worried. She brought Pooch to see me just to be safe. When I examined Pooch on that first occasion, I was not too worried either.
The swelling was soft, like a small balloon containing water. It is common for active dogs to sprain their joints during boisterous exercise, and that seemed to be the most likely cause. I did feel that it was important to rule out other possibilities, so I collected a small sample of the fluid with a sterile syringe and needle which I sent off to the laboratory for full analysis. Meanwhile, I gave Pooch some anti-inflammatory medication, and asked Geraldine to rest her. I fully expected that the swelling would resolve rapidly.
The result seemed to confirm what I had suspected. The cells in the fluid sample were suggestive of an accumulation of joint fluid due to trauma such as a sprain. There was no evidence of anything more complicated, such as infection or tumour cells. When I phoned Geraldine to pass on the good news, I was surprised to hear that not only was the swelling worse, but Pooch was now limping on the leg. This would not be expected to happen with a simple sprain. It was time to investigate the problem further, so Pooch was booked in for x-rays to be taken the next day.
The first x-rays did not show anything dramatically wrong. There were signs of arthritis around her elbow, which is common enough in a seven year old dog. I drained the fluid from the swelling again, bandaged her leg, and sent her home on anti-inflammatory medication for another week.
A week later, the lameness was getting worse rather than better. The next stage of investigation was needed: I arranged for an ultrasound examination. Ultrasound scanning is a useful way of looking at the inside of the body. Its best known use is to look at babies in the womb, but the technique is very useful whenever a three-dimensional real-time view is needed of almost anything in the body.
The ultrasound scan gave the first evidence that there was something very seriously wrong with Pooch’s elbow. A large area of abnormal tissue was identified in the muscle beside her elbow, measuring 3cm in diameter. Using ultrasound guidance, a fine needle was pushed into this abnormal area, and cells were collected for laboratory analysis. It was most likely that the abnormal tissue was some type of cancer, but it was very important to have 100% certainty about this. Other diseases, such as rare fungal infections, could cause the same type of findings. If Pooch had cancer, she would have to have her left leg amputated. This is a very radical procedure, and not something that could be done lightly. It would be dreadful to remove Pooch’s leg and then subsequently discover that she had a problem that could have been cured by a course of anti-fungal medication.
I expected that the laboratory analysis of the needle aspirate would confirm the presence of cancer cells, but this did not happen. There were definitely abnormal cells present, but it was not possible to identify them precisely. The laboratory requested that we take a full biopsy rather than just a fine needle sample. Pooch needed a general anaesthetic for this procedure. A full biopsy involves using a surgical instrument like a mini apple corer to collect a chunk of abnormal tissue. This was done under general anaesthesia, using ultrasound to make sure that the sample was collected from the middle of the diseased area.
I was confident that this time the laboratory would give us a confirmed diagnosis of cancer, but again, the results were inconclusive. The sample was definitely abnormal, but it simply was not possible to clearly define the type of abnormality. I still had a strong “gut feeling” that Pooch had cancer of her elbow, and the correct treatment was amputation of her leg. But without the laboratory results to back up the diagnosis, I could not justify doing this.
Under sedation, I took another sample of fluid from the swelling, as I had done on the first day. Perhaps the disease would have advanced enough to give me a different result this time. Again, the results were inconclusive. It was very frustrating for everyone, especially Pooch, who was now very lame, with an elbow that was as swollen as ever.
I repeated the xrays, and these now showed that the bone around her elbow was being eroded by something. I took yet another sample of fluid from the joint, and this time, at last, the laboratory made a clear diagnosis. The sample contained cancer cells. We now had justification to go ahead with amputation.
The investigation of the problem had been long-winded and had tested everyone’s patience, but in the end, it was worth pursuing the diagnosis with repeated sampling. The operation went well, and within a few days, Pooch was adapting very well to life on three legs. I know that within a month, she will be running around as nimbly as if she still had four legs. Dogs adapt remarkably well to these situations.
Full analysis of the elbow that had been removed confirmed that the problem had been a “soft tissue sarcoma” that can be notoriously difficult to diagnose. There is a risk that the cancer may come back elsewhere in her body, but there is a good chance that amputation has provided a complete cure.
- Rare cancers can happen in animals, just like in humans
- It is not always easy to make a full, confirmed diagnosis
- Patience and persistence are needed, with repeated sampling until a diagnosis has been confirmed