The vet checked a lump on our 7 year old lab mix and it is a mast cell tumor. It's pretty small, but she recommended that it be removed ($500 surgery). I left with the impression that it wasn't terribly serious and we could even let it be if it wasn't getting bigger. After researching this, I think I misunderstood. Who has dealt with this? So far what I read on the internet is that surgery may lead to another surgery if they don't get it all, or expensive treatments if it is more aggressive. While we love our animals very much, we've decided that we will not spend tons of money or put our animals through lots of invasive treatments - especially on something like cancer. I've also read lots of stories about the tumor being cured only to have more pop up again and again. I've also read where it doesn't always heal well. I'll need to make another appointment and get more info from the vet, but I'm curious about what people have experienced. Especially if you had the surgery and that was the last you dealt with it. Thanks!