Growth on dogs underarm—anyone have experience with something that looks similar? (~2yo female rescue supermutt)

To start, I have already gone to the vet about this growth. They first thought it was likely just a wart, but now they think it’s a keratin cyst.

I am just interested to see if anyone has had a growth on their dog that looked similar and if so, what was their experience (since I can’t find any pictures of keratin cysts online to confirm a similarity)!