title: Human herpesvirus 6 lymphadenitis in drug rash with eosinophilia and systemic symptoms syndrome: a lymphoma mimic.
abstract: OBJECTIVE
  Lymphadenopathy, haematological abnormalities and constitutional symptoms are among the non-specific manifestations seen in drug rash with eosinophilia and systemic symptoms (DRESS), an uncommon but potentially fatal cutaneous adverse drug reaction. The ubiquitous human herpesvirus 6 (HHV-6) plays a unique role in the pathogenesis of DRESS, with emerging data suggesting that reactivation occurs in most cases and contributes to the clinical manifestations, including lymphadenopathy. Further, in the appropriate clinical context, demonstration of HHV-6 reactivation may lend support to a diagnosis of DRESS. The histopathology of DRESS-associated HHV-6 lymphadenitis is reported rarely, with morphologic and immunophenotypic characteristics concerning for T cell lymphoma. The aim is to characterize the histopathology of HHV-6 lymphadenitis in the context of DRESS and to highlight this as an important cause of lymphadenopathy that may be a clinical, morphologic and immunophenotypic mimic of lymphoma.
  
  
  RESULTS
  We describe a case of lymphoma-mimicking lymphadenitis in which the histopathological demonstration of reactivation of HHV-6 infection lent support to the clinical diagnosis of DRESS.
  
  
  CONCLUSIONS
  Lymph node biopsies concerning for T cell lymphoma should be evaluated for HHV-6 involvement in a clinical context suggestive of DRESS.
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of North Carolina School of Medicine, Chapel Hill, NC, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Johnson
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of North Carolina School of Medicine, Chapel Hill, NC, USA.
authors.forename: Stephanie
authors.identifier: http://orcid.org/0000-0001-8721-1633
authors.initials: S
authors.lastname: Mathews
authors.affiliation: Departments of Pathology and Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: S David
authors.initials: SD
authors.lastname: Hudnall
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D063926:Drug Hypersensitivity Syndrome / Q000175:diagnosis* / Q000821:virology; D005260:Female; D015654:Herpesvirus 6, Human; D006801:Humans; D008199:Lymphadenitis / Q000821:virology*; D016399:Lymphoma, T-Cell / Q000175:diagnosis*; D019349:Roseolovirus Infections / Q000150:complications*
keywords: Drug rash with eosinophilia and systemic symptoms; T cell lymphoma; human herpesvirus 6; lymphadenopathy