Shawn, I guess it's not impossible to have dual diseases, but not probable, and assume your doctors gave no further indication of other disease. Your cancer was probably shown to be SCC on several biopsies, and a HIV person is also 6x more likely to have HPV oropharynx cancer compared to others, so it's not uncommon there. I don't know how NHL is diagnosed, maybe by bone marrow biopsy, but there are also other high risk HIV cancers, if one wants to look at these also, and also non HIV people can look at other cancers, diseases too, and would probably have symptoms for many. It's best to focus and spend your energy on what's at hand, unless your doctors want to investigate other matters.