May 30, 2019 A 34-year-old man with a history of human immunodeficiency virus (HIV) infection presented to the emergency department with a 1-week history of headache, fever, and confusion. On physical examination, a large, ulcerative lesion was noted on his tongue (Panel A). The patient's CD4 count was 39 cells per cubic millimeter (reference range, 500 to 1450), and his HIV viral load was 197,0..