Résumé : From the results of retrospective clinical and histological analyses it was suggested that the patient, a homosexual Japanese male, had been suffering from a primary immunodeficiency virus (HIV) infection. He subsequently died from acquired immunodeficiency syndrome (AIDS). Three years and 8 months before his death, he had an acute illness, consisting of papular exanthem, fever, malaise, abdominal cramp, and sore throat. Since these manifestations were consistent with a known “infectious mononucleosis-like” disease associated with HIV seroconversion and since circulating lymphocytes were not decreased in number at this point, the patient’s illness was assumed to be the result of the initial infection with HIV. The papular eruption was histologically characterized by a massive infiltration of atypical T lymphocytes that had extensively invaded the epidermis. Our case suggests that such lymphocytic papules are possibly an important diagnostic manifestation of primary HIV infection.