Scab on my Kitty's nose - growing Any advice?

I need advice. My kitty has gone to the vet several times in regards to this scab. The picture is above. They tested for bacteria, fungus, ringworm. He is an inside kitty, never allowed outside. It has been growing. He has had it for about a year. The scab will fall off, there is clear liquid underneath and re-scab again. I have no other cats. Any thoughts? I am really worried about him. He is about 3 years old. I have had him for two years, I adopted him. Please help. Thank you.

I would think the next step is a biopsy where the nature of this lesion can be determined.  It could be a skin cancer, benign or malignant, just as humans have moles that do similar things.  Ask your vet about it.  Maybe they could remove that lesion while sending it for microscopic study.

Thanks for the advice. I will talk to the vet on Monday. Thanks again.