I was told I have a fatty tumor in my neck above the collar bone. What would make it change size?

See MD. If the lump is getting bigger - you should see an md and have further evaluation on this lump. You need to make sure that the diagnosis is correct. Perhaps, you should have some imaging and biopsy to rule out malignant process. A lump can enlarge if this is a malignant process or becomes malignant or if there is infection/abscess or bleeding inside/around the lump.

Related Questions

Was told I have a fatty tumor in my neck above the collar bone- is this normal?

Lipomas. Regardless of location, are usually harmless. If it changes in size, causes pain, it'stime for consult for removal to see if the clinical impression was wrong. Read more...
Lipoma. This isn't "normal" but it's a common item in a common location. If your physician is confident that this is a common fatty tumor ("lipoma") and it's not growing rapidly or causing you inconvenience, it's your choice as to whether to keep it or have it excised. Read more...