Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that Brandy has a cyst on her tail that is large enough to make removing it and having enough extra skin to close the defect impossible.
Unfortunately that is sometimes the case with tail tumors
. If we remove enough skin to remove the tumor we end up compromising blood flow to the end of the tail. When that is the case that necessitates tail amputation.
This should not pose a problem for Brandy. We cauterize the blood vessels and nerves to stop pain and bleeding
and once the incision heals they do very well. She won't miss the end of her tail.
Because blood supply is limited to the end of the tail it can take longer to heal than many other surgery sites. And most dogs do seem to want to lick so the tail often needs to be bandaged and the pup needs to wear an elizabethan collar so they leave the surgical site alone as it heals.
While she doesn't have to have surgery eventually the cystic mass will outgrow its blood supply and break open. That leads to bleeding, and secondary infections and pain. Surgery at that point is more difficult, and there is more bleeding due to inflammation and infection, so healing will be even slower and the urge to lick more pronounced.
Best of luck with your girl, please let me know if you have any further questions.