Possible Alternatives to Cancerous Growth?

Hello, I am looking for some additional advice from another veterinarian regarding my cat. 14 year old female, hx of thyroid issues (managed with medication over the past few years). Right shoulder had a pus-filled cyst with opening approximately 4 years ago. Over the past year, an additional ulcer has formed and is open. The cat licks the wound and has since been given a collar to prevent licking it. The wound has gotten larger over the past few weeks (even with the collar), and the wound is seeping and bleeding. The cat does not appear to be in pain or discomfort, but has recently shown reluctance to put full weight on front legs when jumping down from furniture. Attitude, demeanor, and temperament are unchanged. My regular vet did pathology testing however results came back inconclusive for cancer however could not rule it out. The vet also said that if the ulcer was removed there is no guarantee it would not come back. Any additional ideas on what this might be, other than cancer? Thanks in advance.

Hello.  Please be aware of the contrast between your own vet, looking at a wound (that they can see in front of them), and a stranger online (who has never even seen the wound, doesn't know much about the animal and is only reading a lay persons description).  Even if we were equally qualified and equally experienced - hey, even if I were far more experienced than your vet, which for all I know is easily possible - it is important to realise that your vet can see the wound and therefore, your vets' opinion is infinitely more valuable than anything written here.

Cats can lick wounds open for their own sake- for psycological reasons, perhaps, but definitely in response to pain (even pain elsewhere in the body, such as pancreatic pain).  You say that the wound has continued to grow after a fortnight with no licking - can scratching or rubbing be ruled out?  How about the influence of infection?  Interestingly, cancer often doesn't hurt in itself / isn't licked, although there are reasons why it might be.  I have seen many things that looked like cancer but turned out not to be.  From the little that I know about the case, biopsy might be a good way forward.

Biopsy is so frequently used becauase inflammation can look like cancer and cancer can look like inflammation.

Please do let us know what you decide.