title: Red herrings.
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology; D003937:Diagnosis, Differential; D015658:HIV Infections / Q000150:complications / Q000175:diagnosis*; D006679:HIV Seropositivity / Q000150:complications / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009494:Neurosyphilis / Q000175:diagnosis; D011859:Radiography; D013116:Spinal Cord / Q000473:pathology; D020306:Tuberculosis, Central Nervous System / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology