Please Help Identify Lesion!

[RascyCat]

I recently noticed this lesion on my cat's back. It's close to the base of her tail/top of her leg. She is 15 years old and is now an indoor cat, but she was an outdoor cat for most of her life. It seems like some flakes of skin are coming off, and also some kind of crusty pus (but I'm not actually sure if it's pus, I just don't know what else it could be). It is completely dry, but has been there for at least a week. She doesn't groom as well as she should back there anymore, but we try to brush her as often as we can. She also has some issues with dandruff in that area, but has never had a lesion like this before, at least not that we know of. She doesn't appear to be in pain, but that doesn't mean she isn't. She's still playing, running, and jumping up on furniture just fine. We're going to try to take her to the vet as soon as possible, but any insight in the meantime would be very much appreciated!

 

[Furballsmom]

Hello! I don't have even a thought as to what this could be. Let us know what the vet says, my fingers are crossed for you!

 

[gordonsmom]

Please, please take her to the vet right away if you have not already. I just lost my 16 year old cat last week and I wont go into details as this could be something completely different, but don't take any chances. Hanna also started with a lesion, but as I said, could be different - there are many possibilities.
Please let us know.