george, i think your vet should have explained herself, and done a biopsy.  if it is a tumor, and it isn't growing, and it is benign, then maybe it doesn't need to be removed.  on the other hand, if it is a cancerous tumor, urgency may be needed.  i think overall she seemed to casual about it all, and slightly uninterested.  
i hope whatever it is, the new doctor spends time talking and explaining everything to u.  it might help if u take a list of questions with u.