Lump on cats neck - Goes away for 17 days after Depo Medrol shot given then comes back

[Grey771]

Female Tabby 3 years old named Tulip. She gets a lump that swells to practically the size of a golf ball on her neck and affects her breathing. I take her to the vet and she's given antibiotics and a Dep Medrol shot and the lump goes away within a day or two. 17 days later - the lump comes back. The first or second time the lump was on the right side, but the last two times it was on the left side of her neck. I've tried keeping her on antibiotics but they don't do anything - only the Depo Medrol shot seems to work.

Antiobiotics tried:
10/24/2020 Orbax (lump came back while still on this med) + Depo Medrol
11/11/2020 Convenia injection + Depo Medrol
11/29/2020 Convenia again + Clindamycin Liquid - took liquid for two days and stopped as no effect - Vet didn't give Depo Medrol and didn't listen to me, not happy. No improvement to cats lump so took her back in for Depo Medrol 12/1.
12/1/2020 Depo Medrol + took a needle sample of Lump - 12/24/2020 still waiting on results
12/24/2020 I can feel the lump start to come back thought its still small right now. Previously after 17 days it was huge but its been 23 days now and it's like half the size it was previously.

Diet: Friskies dry food always out + Half a can of Fancy Feast wet food 3 times a day.
Despite the lump the cat is in good health. She could probably use more exercise but isn't fat or anything.

Just trying to figure this thing out since my vets seem to be kinda stumped too.

 

[Grey771]

Also now a small lump has been found in the middle of her back above the shoulders.

 

[FeebysOwner]

Hi. I think you will have to wait for the results of the needle aspiration to help narrow down the source of the issue. It could be anything from endocrine/glandular issues to arthritis, and a host of other conditions in between. Because the Depo helps, the lumps are obviously associated to something causing inflammation.

Do let your vet know that a new lump has developed and in a 'new' location - that might give them some additional information to help assess what they see in the test results.