Maybe I am a bit late to enter this thread as it's been a while since any post so my experiences may be too late now anyway.
My secondary was found (lump to side of neck) and after 3 FNA test found to be malignant but no sign of primary.
I then had MRI scan with no result followed by a combined pet/ct scan which resulted in no primary found.
I was being treated under the barts MDT. At their next meeting they recommended removal of both tonsils as the most likely site of the primary. Although as far as i know they did no tests (fna etc) to the tonsil.
Fortunately for me the tonsil, or one of them at least turned out to be the primary.
WAS I JUST LUCKY in this outcome, certainly i no longer have the worry no primary and for that i am very grateful.