Cyrus has a bump

My 9 year old male kitty, Cyrus has had a bump on the lower part of his tail (close to his back) for a few years now that has not grown too much but I'm thinking it is just a fatty tumor as my mother's animals have gotten them in the past. When should I be concerned or what should I look for? He has had it for about 3 years, it has grown only some, he is overweight, but not obese. The bump moves mostly freely (it does not seem attached to the tail). He acts just fine, eats and drinks fine. Plays with his siblings (my other kitties), and gets plenty of love and attention all the time. My cats are indoor, so I do not take them in for shots yearly as they do not come in any contact with any other animals or the outdoors. He is neutered. Any ideas? Thank you!

[nancyjac]

My 14 year old has one as well on his side.  It is most likely a sabacious cyst.  It initially fills with fluid but over time will harden.  It can be drained but if it doesn't seem to bother him you might just want to leave it alone.  If it continues to grow or he becomes uncomfortable with it (excessive licking or biting in that area), it would be a good idea to have it removed or drained.

[jettsmama]

Thanks for the reply! Is a sabacious cyst also known as a fatty tumor? Do you know why they get things like that? It doesn't seem to bother him at all but I watch for it quite often.

[nancyjac]

Well a cyst and a tumor are not the same thing.  A tumor is an abnormal growth of tissue while a cyst is just a membranous sac.  But a sebaceous cyst is one that fills with a fatty fluid that can harden.  They can form for a number of reasons including, inflamations, infecections, blockages, and even being genetically disposed to them.