I am 18 years old and inactive, causing fatty thighs and butt. I've known about the lump for a few months and have been too scared to get it checked out. The lump has not grown in size since i found it and does not hurt. It is just under the skin and moveable. I have been telling myself its a fatty lump due to the fact its located on the part of my thigh with the most fat. I've been scaring myself reading of sarcoma and such and was wondering if my symptoms are that common in a cancerous lump or most likely fatty.