The waiting is the hardest as is resisting the urge to consult Dr. Google. Saying "Don't think about it until you get the results" is useless (I know I couldn't do that nor resist the lure of Dr Google) so just keep talking here, have a good scream when you need to and whatever else helps you deal with stress. My vote is that the vet has been overly alarmist and we can all commiserate with you in complaining about him once you get good results back.
Haha I knew you'd understand the Dr. Googling!
So my latest diagnosis (purely my opinion of course) is that it's a mast cell tumour but we need to wait for the grading. Part of my investigation that has lead me to this diagnosis is how adamant the vet was about her wearing her cone 24/7 and how important it is that she doesn't get to rub, scratch or damage the lump.
My googling has found :
"Tumors can be irritating and dogs
will scratch, lick, or bite the mass and surrounding skin. This trauma causes the tumor cells to release the chemicals in their granules leading to a localized reaction. In more serious cases, the chemicals can affect the entire body, causing severe gastrointestinal bleeding and even an anaphylactic reaction, which can be
fatal if untreated. "
Plus, it seems mast cell tumours are more common in retrievers (and some other breeds).
So there we go.
