Tuesday, April 19, 2011

411. A fast-growing backside tumour in an old Dachshund - a lipoma or liposarcoma?

"The lump on the right backside grows quite fast," the lady owner pointed to a 1.5 x 2 cm globular swelling to the right of the anus. "There are 4 other smaller lumps."
She was concerned about the large lump as it grows bigger every day. Could this be a liposarcoma (malignant growth) instead of a lipoma? Although middle-aged and old dogs, overweight female dogs do develop lipomas which are benign, I don't ask the owner to wait and see approach.

In one instance, Vet 1 had asked the owner of a Labrador Retriever to wait and see when the owner complained about a small globular growth above the neck of the dog. As typical of the busy Singapore owners, the owners waited till the lump becomes half the size of a tennis ball. When I saw it, it was a malignant tumour as it recurs after excision. "Well, Vet 1 had said that there was no need to remove the tumour when it was small," the owners said. Eventually, the dog had to be euthanased. From this experience, it is best NOT to advise the owner to wait and see. Give the owner the option to get the tumour resected and let her decide. The vet should not assume that every tumour under the skin is a lipoma and is benign.

In this female spayed Dachshund of 8.5kg, the owner had knowledge and asked me to operate. She was worried about the anaesthetic risk. A blood test showed the dog to be healthy for anaesthesia. Still the risks of death on the operating table are made known to her. She accepted the risks.

"Don't ask the vet to perform surgery during weekends or public holidays as the vet is busy and may need to rush through the surgery," I advised her and most clients that any rushed anaesthesia and surgery will not be in the interest of the patient.

I operated on April 19, 2011, a Tuesday morning at 10 am as scheduled and the owner arrived early. No food and water from 10 pm the night before. She used a marker pen to ink the 5 lumps as instructed by me. I still took one hour in total just to remove 5 fatty tumours and that included preparation, IV drip and surgery. The electro-surgery took around 30 minutes. Can't be shorter.

SEDATION
0.2 ml xylazine IM. My new assistant Mr Min asked if I wanted to give xylazine IV as I sometimes do. "No," I said. Isoflurane gas by mask was smooth and uneventful. The dog slept like a log. Intubated the dog to get oxygen and gas in. The anaesthetic machine was not leaking gas after industrial glue was applied to the hairline crack in the base tubing 2 days ago. 0.5 - 2% isoflurane gas was sufficient. "Keep to 0.5% and not less," I said to my assistant as he knew that the less the safer for the patient. But too little may lead to the dog waking up and delaying my surgery! A good assistant during anaesthesia is worth his or her weight in gold as vets don't have the luxury of the tax-payer's money to have an anaesthetist and the best equipment like the Singapore General Hospital.

ELECTRO-RESECTION
I like electro-surgery for such cases. No bleeding at all when I cut the skin of over 3 cm long to expose the pure white globular fatty tumour of 1.5 x 2 cm in size. Not one drop of blood. If you use scissors, you need to undermine the skin. The fine wire electrode just skim below the skin and the fatty tumour parted. I excised the base of this tumour attached to the muscle layer. I could see small red blood vessels of around 2 mm supplying this tumour with nutrients. This could be a liposarcoma as it grows fast.

Still no bleeding after I excised from the base of the skin to the top of the muscle layer and brought out the whole tumour intact. That is the usefulness of electro-surgical electrode (see image). There is no need to use scissors to undermine the skin and damage this fragile fatty tumour, pure white like snow and fragile too.

The owner came at around 11.30 am. The courier man had just taken the tumour inside the formalin bottle to bike back to the laboratory. So I could not show her but I have the image to show her. The other 4 small pieces of 3mm x 5mm were discarded as I did not keep them. However, she could see the stitched areas (3/0 absorbable sutures, horizontal mattress for the backside and simple interrupted for the others)

DOG POOPS
Unfortunately the dog started pooping. Brown solid stools started coming out from the anus. Surgery stopped and stools removed. Should have asked the owner to bring the dog to the toilet at home or plug the rectum.

"Is the dog awake?" the owner came at 11.30 am expecting a drowsy old dog. Well, this was the first time I met her and so she would have known about dog anaesthesia done in other clinics that use injectable IV anaesthesia. Isoflurane gas always allow the normal healthy dog to wake up within 10 minutes after completion of the surgery. As if it had a good nap. The surgery was not particularly painful but I gave the painkiller tolfedine SC and oral for the home.

"Yes," I said. "She woke up very fast after the end of anaesthesia." Xylazine 0.2 ml IM is a very low dose for a 10-year-old overweight Dachshund of 8.5 kg. I did not use xylazine IV this time as IM would be safer in an old dog, in my opinion.

"I had excised the 4 smaller tumours completely with their skins," I explained to the owner. "The backside tumour is large and if I removed it with the skin, there will be a big hole and the hole may not heal. So, I removed as much as possible under the skin and above the muscle. If it is malignant, it may recur." It is best to communicate this to the owner. The skin wound was over 5 cm long just to expose this 2x1.5x1.0 cm tumour and so there would not be enough skin to close the wound properly. I don't want a dog with a big gap in the backside due to the non-healing of the wound as this area is a high-tension area making wound healing difficult.

"Can you operate the other Dachshund? He has only 2 tumours similar to this dog?" the lady in her 40s asked. Red blood had oozed out from the dog's backside now despite the two horizontal mattress stitches closing the wound. "Your blouse and your handbag is stained with blood," I told her. "It does not matter," she said. The dog was alive and that was what mattered in her world.

She had earlier wanted two dogs done at one day. There are pros and cons for the vet. Pros - revenue comes in and client may go to the competitor if there is a delay. Cons - rushed job, not in the interest of the dog as mistakes in anaesthesia can result in the dog's death.

"It is always best not to stretch the vet as he has other surgeries and things to do in a day," I tried to educate this lady. I had asked her to bring just one dog today for the simple reason that I could focus on this dog alone and not be distracted.

I also did not want her to be waiting outside the reception room while I operated as to maintain a peace of mind during operation and not having a worried owner pacing outside the operating room.

"Well, it is best not to tempt fate," I told this personable lady. "Your operated dog is alive and well. It is not a guarantee that old dogs undergoing anaesthesia will survive and so it is best not to do another one on the same day. I am actually worried when I operate on old dogs! I don't even look forward to any old dog surgery." It is not that I am superstitious or can't do the 2nd surgery. There was no emergency for the 2nd dog to be operated on the same day and I do have a lot of things to do.

"Thursday will do," I said. Well, the lady was busy on Thursday. "How about Friday?" she asked. "If you come early on Good Friday at 9.30 am, I will operate as most clients don't come so early." However, I can understand that the owner is worried about the tumours in the sibling Dachshund becoming malignant through delay in surgery and she preferred me to operate. I had assigned Dr Vanessa to operate as this is a simple surgery. It is the anaesthestic death that the owner is very worried about and this must be understood.

Although there will be just 2 small fatty-like tumours, the whole procedure of preparation before op, sedating and giving the isoflurane gas and the IV drip and surgery can take 45 minutes in the 2nd dog.

No wonder, many vets just give injectable anaesthesia. No need to "waste time". I prefer isoflurane gas as it is much safer and the dog wakes up fast. But it sure takes 4 times as long. But in the end, the owner just wants a live dog and giving the owner a living dog is what she wants. Isoflurane gas gives a high safety margin and so I seldom use injectable anaesthesia in old dogs or young ones.

Injectable anaesthesia is also safe but it needs topping up in small amounts if the surgery takes longer than expected. A higher risk is involved in using injectable compared to isoflurane gas but usually a very small amount is injected and that is quite safe.

Well, each vet has his own choice but deaths on the operating table simply ruins a vet's reputation as owners spread the word and so, over the years, I rarely use injectable anaesthesia. It is preferred that other vets do the old-dog anaesthesia and surgery!








P.S LIPOSARCOMAS are uncommon malignant tumours of the fatty tissue. As this lump grew fast, the owner agreed to the histopathology to be done by the Lab.
Classified as low, intermediate or high-grade liposarcomas. With low and intermediate grade, the risk of spread to other parts of the body is low. With high-grade, the risk is much greater.

UPDATE APRIL 22, 2011
Histopathology results: A lipoma with no malignant cells seen. This is good news for the old Dachshund.

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