HEMORRHAGIC manifestations of infectious mononucleosis are not uncommon. Virtually every organ system has been involved.1Gross hematuria is quite rare, and renal biopsies have not been done in the few cases reported. Granuloma formation in the bone marrow in infectious mononucleosis is a phenomenon which was first reported less than 20 years ago.2This finding, although reported to be quite common, does not yet seem to be within the realm of common medical knowledge. It will be the purpose of this paper to present and discuss the significance of a case of infectious mononucleosis associated with granulomatous changes in the bone marrow, unique renal lesions, and gross hematuria. Report of a Case The patient is a 19-year-old white boy, who had been experiencing confusion, visual hallucinations, chills, fever, sore throat, and grossly bloody urine during the week preceding his hospital admission. The patient was seen by a local