Hi Rosie and thanks so much for posting.

I'm afraid I cannot tell you what your lump is, but most people will get lumps and growths on their skin at some point. These are usually harmless and can be caused by many things.  If you have noticed a change in the lump or it has become painful or red then make a GP appointment so they can examine you.

Sarcomas are a rare form of cancer and it is much more likely that it is something else causing your symptoms, especially as this seems to have been there for a number of years

Lipomas are normally soft to touch and dome shaped.

It is helpful that your GP has seen the lump and is not concerned, but perhaps you would find it useful to make another appointment to talk things through, as it sounds like this is something that is causing you a great deal of worry. 

You may find it helpful to talk things through with one of the nurses on our helpline.  Our Freephone number is 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.

Best wishes

Rachel