Tilly, a stoic collie, presented with a whopping cancer on her leg. This was thought to be composed of fatty tissue from samples that had been taken by the referring vet, but the mass looked so unlike typical fatty masses that we double checked with biopsies. Indeed it was of fatty tissue origin. Fatty masses are usually benign, but the possibility of infiltrative or malignant variants were strongly suspected.
The best chance of achieving a long term cure was amputation. If we attempted to remove the mass and spare the leg, the owner would have to accept that such an attempt would carry risks of local recurrence of the tumour. In addition, there might be some long term reduction in limb function because certain nerves would be damaged/removed along with the removal of this huge mass.
The owner pondered their options, but decided that they really didn’t want a limb amputation. So excision of the mass was performed. Our plan for closing the wound initially involved raising a large skin flap from the underside of the abdomen, but unless we were sure that the mass was removed completely, this would involve the risk of “seeding” (spreading) tumour from the limb up onto the body wall. So we planned to remove the tumour and then manage the excision site as an open wound for a few days to allow time for the lab to confirm that margins of excision had been achieved. The large open wound would have been covered with “tie-over dressings”. These involve using sutures to hold dressings over open wounds. There would then have been a requirement for a second anaesthetic and a second surgery after a few days to close the wound with a skin flap once the lab results were in.
So we were delighted when it transpired that we were able to close this huge wound with local tissue at the time of excision at the first surgery. We used a technique called meshing to maximise the use of the remaining skin that was available around the leg at the level of the wound. The use of a number of small cuts allowed the remaining skin to be stretched like a string vest. In essence, we swapped one massive wound for 40-odd tiny ones. These would then heal over in a matter of a couple of weeks. We took pains to minimise the risk of spreading of any residual tumour around the remaining leg while the mesh incisions were made. However in the event of local regrowth, no further attempt at excision would have been contemplated in any case, and so local seeding wouldn’t actually have significantly affected our future options anyway.
By keeping all surgery “within the leg” , the owner did still have the future option of amputation at a future date, in the event that tumour does go on to regrow locally and necessitate action. The owner was very keen to avoid amputation, and amputation will only ever be done as a last resort. It was however good to know that we have the option if we need it.
Tilly woke up from her anesthetic, stood up and ate up her tea as if she’d just been out for a walk round the park! We dressed the leg and this dressing was changed 3 days later. We were delighted with the wound; the wound was holding together nicely and the meshed areas were looking exactly as they should. She was walking normally on the leg! The central part of the wound did open a little, but it was a fraction of the size that it would otherwise have been and it healed very nicely left to its own devices.
Some of the photos of the excision are a bit too graphic to show here, but these will give you an idea of the scale of the mass!
15th March 2014