A 64-year-old man with HIV and suppressed HIV RNA levels (on antiretroviral therapy) presents for evaluation of a lesion in his lower jaw under his tongue. The lesion is diffuse and white, with areas of erythema and ulceration, and extends from the lingual gingivae of the lower anterior teeth to the floor of the mouth (Figure 1). This area has become painful when swallowing. A biopsy of the lesion reveals squamous cell carcinoma. He has never been a smoker and has never chewed tobacco.