About two years ago, I felt a small lump under the skin of my right upper arm. It is slowly growing and is blue. My doctor (general practitioner) says it is an epidermal inclusion cyst but nothing I can find on internet confirms this. Now my right arm is getting noticeably smaller than my left arm. Lump does not protrude and is not sore but the blue color is obvious to the naked eye. If my R arm was not getting smaller, I would not think too much of it. I'm 65 yrs. old.