Hello, just saw this :).
How did the surgery go?
I only knew one cat that got a TECA on both sides due to chronic changes in his ear canal skin. It was always inflamed and extremely itchy. One side even had a tumor in it. Both surgeries went well, but he had to wear a cone for a while, because he always wanted to sratch.
After complete healing he was no longer itchy and loved being touched. before that was painful for him.
I hope your cat heals fine, too!
Honestly, I’d be looking for an oncology specialist to determine if it really is a tumor of some sort.