I never mind sharing our 'surreal' experience with full technicolour gory details LOL
The short answer in your case, is who knows- that is really not meaning to be flippant, but there is so much down there , in the gullet, and whenever you go for any procedure they always look for anything and everything and for most investigations like that they tKe biopsies when down there.
I would imagine you have an appointment brewing to discuss it with Doc's.
As for symptoms, if you are talking about oesophageal cancer, they are hugely varied. It is not seemingly a cancer that likes to be consistent in its presentation. I think it would be fair to say, if you flick back through post, most of us hand some trouble swallowing food, completely out of the blue, in our case one day he was fine, literally the next food getting stuck on the way down.
My guy has no voice change as a symptom at all- unless shouting at the kids(:, or TV LOL. Serves him right eh
Hope this helps, but I bet you are in a right state at the mo, wondering what is going on- fear not we are all 'experienced' in the rollercoaster that keeps on coasting- ask away.