Mast cell tumour

We're in shock as our 8 -1/2 year old Pembrokeshire corgi has been diagnosed with an ulcerated mast cell tumour in her stomach - this comes out of the blue although looking back we can see some of the symptoms [loss of appetite, depression] developing over the last two months. Two years ago she developed what the one vet decided was a fatty tumour and he ignored it - although I think he aspirated it. Last summer, when it had developed to a point where she looked like the hunchback of Notre Dame, his new partner on first seeing our dog announced it had to be removed immediately. The official verdict was that it was "only a fatty tumour". I am now very suspicious as what I've read about MCT, they usually manifest themselves on the surface. Once they move inside, then it's lethal.
Has anyone else experienced such a misdiagnosis? I know that they never sent a sample to the path lab.

Lipomas or fatty tumors can be distinquished by the Vet usually very easily via needle aspiration and staining. Very few will follow up by sending the sample to pathology because it's easy to distinquish. In fact when they place the aspirate on a glass slide a fatty tumor will have a gease like or fat like beading up appearance of the fluid.

There is one hitch. As a Lipoma gets larger there is potential for a cancer to develop in its center and hide. That is why usually a Lipoma becomes larger a Vet may reaspirate, and/or remove it.

However what you have described is a separate abdominal MCT. What you noticed over the past few months should be emphasized. Too often we as pet owners think that our older dogs are just slowing down, or should be slowing down. Naturally older dogs are not going to act like pups, but unless they have arthritis or some other disease condition their energy level should remain relatively constant the later part of their lives. With my Lymphoma puppy, 6 months before she was diagnosed she started to ascend the staircase by walking at 30 degree angles instead of walking straight. She also tired more easily. Cancer takes a while before it reaches a critical mass for full blown clinical disease. But in the time leading up it can greatly alter the dog's biochemistry, making it feel more tired.

Your best course with MCT is surgery to remove the tumor, and if there is any doubt about getting clean margins to follow up with local radiation. If the Vets find metastasis has occured then Chemo with Vincristine (or Vinblastine) along with Prednisone, and Cytoxin will give varying degrees of remission from just a couple of months to close to a year. Additionally Lomustine has success against MCT, and is a mustargen in the same class as Cytoxin.

There is evidence Omega-3 fatty acids can suppress the inflammatory responses of mast cells, thus fish oil supplementation might help a little. Other studies indicate Vitamin-E also interferes with the mast cell releases. H2 antagonists such as Cimetidine or Rantidine also will help, not to mention protect the stomach against the irritation of Prednisone. Finally anti-histamines help slow down the progression of MCT. After all that's one of the "normal" functions of mast cells - to release histamine. Benedryl or a precription anti-histamine from your Vet will help.