Get Your Dog Care Questions Answered by Experts
My nae is Joan and I am a Vet tech for 30+ years.
Is the lump solid or mushy?
Does it feel attached?
In dogs we see quite a few lumps and bumps pop up. Many times they are nothing more than a Lipoma which is a Benign fatty mass. Sometimes we see a cyst which can have fluid or a cheesey material in it and this usually needs to be opened and cleaned out and an antibiotic given. Those can occur when the dog may have gotten an insect bite or it may be a sebacious cyst. That comes from an oil gland that can get clogged and continues to grow. They are very common: http://www.petplace.com/dogs/sebaceous-cysts-in-dogs/page1.aspx
We may also have a tumor, that can be bengin or we can have one that is cancerous. At this point since we do not know what we are dealing with, the best course of action would be to have your boy into the Vet and they can do an X ray and also what is called a fine needle aspirate. That is where they pull some of the cells out and send them to the Lab for analysis. Once this is done you will know what type of lump you are dealing with and what can be done if anything (removal or leave it). http://www.petplace.com/dogs/skin-growth-lump-swelling-or-mass-in-dogs/page1.aspx