My cat Sasha had a bump removed from the top of her head last week and
today the vet called and reported that the bump was a mast cell tumor.  
He said that these tumors tend to be much more serious in dogs than in
cats, but there is a chance that the tumor could return.  He said that
should that happen he would again remove the tumor and take more of the
surrounding tissue, and if it recurs again, then radiation treatment
might be necessary.

Obviously I am hoping that we are one and done with this, but I am
wondering if there is anything else I should know or be on the lookout
for regarding these tumors.

Thanks!