In situ demonstration of Epstein-Barr viral genomes in viral-associated B cell lymphoproliferations.

Thirteen cases of benign and malignant Epstein-Barr viral (EBV)-associated B cell lymphoproliferations were examined by in situ hybridization studies performed on formalin-fixed, paraffin-embedded tissue sections. EBV nucleic acids were identified in a minority of lymphoid cells in five of six cases of benign infectious mononucleosis studied in tonsil or lymph node specimens. No evidence of EBV was found in two splenectomy specimens from patients with infectious mononucleosis. EBV nucleic acids were identified in one case of fatal, infectious, mononucleosislike immunoblastic proliferation, and were especially concentrated in areas where there were sheets of immunoblasts associated with necrosis. EBV nucleic acids were identified in all four cases of EBV-associated post-transplant lymphoproliferations, including three cases of non-Hodgkin's lymphoma in which a majority of the neoplastic cells contained EBV nucleic acids.