Human herpesvirus type 6 (HHV-6) has been well described as an agent in immunocompromised hosts, but is a rare cause of acute lymphadenitis in immunocompetent adults. We report an immunocompetent adult with HHV-6-associated acute lymphadenitis. The patient was an elderly man who presented with fever and generalized lymphadenopathy. Microscopically, the lymph node showed diffuse paracortical expansion and scattered large atypical lymphoid cells with large nucleus and eosinophilic nucleoli, resembled immunoblasts. Intranuclear eosinophilic viral inclusions can be found. Immunohistochemical study showed that the large atypical lymphoid cells were positive for CD3 and CD4, but negative for CD8, CD20, CD79a, CD30, ALK, CK, EBV-LMP, and CD56. The antibody against HHV-6 envelope glycoprotein highlighted the viral inclusions which were mostly cytoplasmic with a Golgi distribution. Literatures of HHV-6 associated acute lymphadenitis in immunocompetent patients were reviewed.
Keywords: ALCL; HHV-6; HL; immunocompetent patients; lymphadenitis.