Cat has new lump on hind leg

My five year old male cat has a lump on his leg I recently noticed. I felt it and it feels firm but surface deep and will move around with the skin. I’m worried because his fur on his leg has been kind of bald for a while but the lump is new. I’m bringing him to the vet but I’m very anxious and would like to hear what anyone has to say about what it could be. There’s a few scabs in that area as well.

Hello - this lump appears to be in the skin, and from your description I wondered whether it might be inflammatory (something aggravates the skin, inflammatory cells move into the area and get a little carried away).  This would tie in with your hair-loss description and I find myself worrying about flea or insect bites, in particular fleas, nettle stings, allergies and so on.   However, thats not the only story I can concoct to explain this lump.  Inflammation due to licking as a response to arthritic, soft tissue or even abdominal pain is a possibility.  So is cancer, aggressive or benign.  But common things are common and a flea-check sounds to be a good place to start.

Even if it is fleas, there are now secondary effects so a vet appointment sounds to be a good idea.

Ok, he is a tripaw and this is his only hind leg. He is also somewhat chunky so vets said arthritis would be a worry for him.

I also wanted to ask, I was worried about swollen lymph node but does this seem too low to be the popliteal?

Enlarged lymph nodes do remain a possibility but are not usually itchy and are not usually associated with hair loss.  Enlarged LNs are not always down to sonething sinister, either.  I can't orientate myself very well on this picture so I'm not going to comment on the location; the pop LN is normally behind the knee and quite deep - usually felt rather than seen. What I would say, is that your mind has done what mine does at the Drs (vets are terrible patients - we know everything that can go wrong with bodies).  So I, like you, in a personal context, would go straight from 'lump' to 'something terrible.'  Worrying doesn't exempt us from a bad outcome, but there are plenty benign things that this could be from the little context I have here.  Cancer doesn't usually itch, for example, although that doesn't rule it out. If you are worried that the patient seems ill or the situation is deteriorating, call the emergency vets.  Otherwise, please do look after yourself as well as your cat.  This includes seeking an opinion in context, which I promise will be more useful to you than mine.  I hope that they can set your mind at rest.

Thank you, I am a medical student so I see what you mean! If I felt this lump on myself I would think it’s a keloid (feels exactly like one I have), but there seems to be so much less reference and more unpredictability for cat lumps so I get lost in worry.