The base of tongue is the I/3 posterior of the tongue where lingual tonsils are atop, so it's possible, in some, to see, feel, it, if the mouth can be opened wide, tongue can be extended, have no gag reflects to tolerate. That's one area the doctor checks on a palpable exam. Most HPVSCC have no visual indication for cancer, as opposed to tobacco related cancer with ulcerizatipn, etc. I had three flex scopes, and cancer was not seen, but was on the CT, and PET, which was confirmed by a direct biopsy. The nodes were checked by FNAB before that, and confirmed metastatic cancer cells,, , so they knew it was most likely coming from the oropharynx.