possible tumor on tail

I took Beavis (on leash) outside a few minutes ago to enjoy the sunshine and get some nibbles of grass and while petting him outside i noticed a knot on his tail-- Its about the size of the middle joint of my pinky finger and nice and round. I squeezed it and it didnt seem to bother him. He didnt bite me-- I plan on taking him to a vet sometime this week probably wednesday depending on how the weather is. He is 18 yrs old and in good condition-- I had a senior panel done on him with t4 back in March this year. His values were those of a healthy kitten for the most part. We saw a cat only vet then that i had a good opinion of then but am thinking about going to another one. Shes pricey (shes in a pricey part of houston though) charges extra 20 something bucks if you drop your pet off and have themlook at your pet at THEIR leisure-- She seems competent but Ive heard some not so good things about her in the recent months.
Oh now im rambling.

Are tumors common in older cats? kinda like warts on older dogs? I googled but didnt find much on tail tumors. Anyone have any experience with tumors on the tail?

Please keep in mind Beavis will be seeing a vet this week -- probably wednesday as thats the day I'm off work.

Tumors are VERY common in geriactric felines. I say that not to scare you, but just to let you know it's not uncommon. At 18, that is not an uncommon thing for your kitty to have. Keep in mind though, that just because it could potentially be a tumor- does not mean it is necessarily cancerious- it could be benign. I think you're doing an excellent thing by planning on taking him into the vet this week. (Also, if your vet is pricy, why not get several referals with your other local vets in your area should he need an operation or other work- make sure they all agree on the same thing so that he is not unnecessarily subjected to anestesia and the knife if he doesn't need it. It could just be a cyst from a clogged hair follicle. Those are not uncommon. My prayers and vibes are with you- definitely have your vet take a look at it....if it is a tumor, you want to make sure you have it seen about immediately so that it doesn't spread if it is malignant. Good luck! Keep us posted!

Same comments as StarryEyedTiger - only because my friends cats had one on his tail (back in UK and a few years ago) She took him to vets and due to his age, 15 at the time, they recommended to leave it - it wasnt bothering him, it didnt hurt and all his other faculties were fine. They said it was a fatty deposit pad It caused him no problems.

So heres sending lots of positive {{{{{ vibes }}}}} for when you get to the vets and some from my kitty-crew