Elderly boy with lump in ribs

[TheGonnagle]

I wonder if anyone has experience with something similar?
My elderly boy cat (19) has developed a lump on his side. It feels as though it is under the ribs or in them(?). He has been up and down recently, has become much more clingy, struggling to get up and down the stairs etc but still retained his ENORMOUS appetite.
Today is different. He doesn't want his dinner (will make an exception for poached chicken), hasn't really moved from the sofa and is clearly in pain. So I've given him a dose of Loxicom which has made him more comfortable but things aren't right.
I was thinking he had maybe hurt himself until today but now.....wondering about some sort of cancer? His breathing is really laboured
I'm obviously going to take him to the vets tomorrow (he was only in for a T4 test for his thyroid last week!) but I was wondering if anyone had experienced similar?
Sorry for the ramble, just fretting about my wonderful gorgeous old boy.

Sorry I don't know what it could be but just wanted to say he's obviously a much loved and cared for cat and how much of a worry it is when our very elderly pets are poorly
I hope the vet can help you tomorrow, I'll be thinking of you

You've done all you can right now, see what the vet says tomorrow.

Will he sleep on the bed with you?.

He is indeed a much loved boy. No, he won't sleep on the bed, he's currently lying on the radiator pipes behind the sofa. I'll let him stay there I think. I can't believe how downhill he's gone in 24 hours

Nothing you can do right now, I fear. Let us know how the vets goes tomorrow.

Thinking of you both.

So it was lung cancer. He went peacefully, purring gently, out of his mind on pain relief and with his forehead rested on mine.
My wonderful ginger boy.

I'm so sorry, you did your best for him.

Oh bless, you certainly did the right thing. RIP ginger boy and for you OP.

Awww im so sorry for your loss ** made me tearful as i have a gorgeous ginger boy too and can't bare the thought of losing him. Keep thinking about your special memories and all the wonderful years you had with him x

So sorry TheGonnagle, he sounds lovely. I also had a very old ginger boy who had to be PTS because of cancer, it is always hard to let them go

Thank you all
We're going out for pizza tonight in honour of the day he managed to sneak up on dd, steal ALL the cheese off her pizza and run off carrying it like a big cheese beard!
He was so naughty, and so ace!

I am so sorry for your loss. He sounds wonderful and a real character.

I'm so sorry, he sounds amazing

He was the best. The house feels empty tonight even though psychoblackgirlcat is trying her hardest to be comforting.
Isn't it crap doing the right thing sometimes?

There's a design fault in them, they don't live long enough.

Yes. It's very hard.

The only consolation I can give you is that not acting in time is much harder to live with in future years.

It is crap I agree. I think it's one of the toughest things about being cat staff. Have a good reminisce (love the pizza cheese story) and a good cry.
We had a panic visit to the vet today and I just dread the day we have to make that decision.