Just to add to this -
after surgery to remove my cancer (colon and surrounding lymph nodes), CT scans found numerous things of concern, from kidney and liver cysts, thyroid nodules and 6 spots on the lungs. My treatment was chemo in case of malignancies elsewhere. We did scans quarterly to watch those spots for change in size and check for any new spots as well as the CEA work. None of them grew, they are too small to biopsy and no new ones have appeared so nothing is being done with them.

Yours is different because it's a new spot which may or may not be cancer and may or may not be growing.

I have one suspicious spot in the area of the surgery which was declining in size (that's good), but the last scan 4 months ago showed it increasing in size (not so good). So they shortened the scan interval from 6 months to 4. We will see after the scan/CEA test next week.

The net of it is that a) they don't know and b) because of it's tiny size, can't biopsy it to find out. The next scan and blood work may give some better data to work with. So for me, it's keep doing regular surveillance scans and blood tests until we know more per my oncologist. I guessing/thinking your situation is similar.

All the best to you.