Booster shots and lumps in cats
This lump may only be a soft tissue reaction to the vaccine and its adjuvent. If so, then it should clear up in approximately 6 weeks. And this is the majority of these cases, so don't be needlessly frightened. If however it is more serious, then biopsy and surgery with wide margins may be indicated.
The potentional problem is a tumor type known as fibrosarcoma, and is a consequence of vaccination. I doubt this is fibrosarcoma (incidence rate is 1 per 10,000 vacciinates according to one study), but a heads-up warning never hurts.
In my practice I vaccinate according to need and also on a three year schedule. Additionally, all cats are vaccinated at specific sites to determine which vaccine was the culprit, and to make surgery more effective, as well as less disfiguring.
If cats are exclusively indoor, then I discuss the possibility of not vaccinating, assuming this is a legal option. Discuss this with your veterinarian for more information.
Dr. Van Lienden
Dr. Raymond Van Lienden DVM
The Animal Clinic of Clifton
12702 Chapel Road, Clifton
Virginia, U.S.A. 20124