possible 2nd reoccurance after 2 years

I wrote some posts a few months ago writing about my Tg being nondetectable for almost 2 years post TT and lymph node removal.
Tg came back in March at 14, with body scan negative.
Had bloodwork of Tg done a few months after that and it came back at 1.1. (Mistake in the lab? No one knows.)

Went to new dr who ordered a sonogram of my neck w/new bloodwork. Don't know bloodwork yet, but sonogram dr at hospital came it and looked at the pictures and said there was a spot that he feels pretty confident that it is thyroid tissue.
So, even if it is cancer or not cancer, I know it has to go.

I have a drs appt coming up for my endocrine to talk to me about what to do next.

Has anyone had a reoccurance of tissue and what have they done? I had in April a thyrogen injection before body scan which showed up negative. The sono dr said they may want to 100% prove that it is thyroid tissue w/another body scan.
Since I just had one w/thyrogen injection I would think they wouldn't do it that way again. I would think they would want to be more definitive and have me go hypo for 6 weeks then the body scan.
What route has other drs taken? After sono, have they done a biopsy to prove the tissue instead of body scan?
I also know that you can't leave even good thyroid tissue in the neck and if it is definately that then would have to be removed with radiation.
Any other insights?
Michelle