title: Infectious mononucleosis. Diagnosis by in situ hybridization in two cases with atypical features.
abstract: Two cases of infectious mononucleosis are reported in which in situ hybridization studies were of use to distinguish this disorder from non-Hodgkin's lymphoma. One patient was an 80-year-old man with a tonsillar mass that histologically resembled non-Hodgkin's lymphoma and, on fixed tissue immunohistochemistry, appeared to contain a population of cells anomalously coexpressing the B-cell marker L26 and the T-cell marker Leu-22, suggesting diffuse large-cell non-Hodgkin's lymphoma. The second patient was a 43-year-old woman with inguinal lymphadenopathy that, on histologic examination, also mimicked diffuse large-cell lymphoma. In situ hybridization studies for Epstein-Barr virus revealed both cases to possess EBV DNA in a pattern characteristic of infectious mononucleosis. In addition, in situ hybridization studies for immunoglobulin light-chain mRNA demonstrated a polyclonal pattern of kappa and lambda mRNA expression. This report demonstrates the utility of the in situ hybridization technique as an adjunct to routine diagnosis.
authors.affiliation: Division of Pathology, City of Hope National Medical Center, Duarte, CA 91010.
authors.forename: S S
authors.initials: SS
authors.lastname: Shin
authors.forename: G J
authors.initials: GJ
authors.lastname: Berry
authors.forename: L M
authors.initials: LM
authors.lastname: Weiss
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D003937:Diagnosis, Differential; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000378:metabolism; D007146:Immunoglobulin lambda-Chains / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D007244:Infectious Mononucleosis / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D037181:Lectins, C-Type; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis / Q000473:pathology; D008297:Male; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D004279:DNA, Viral; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D037181:Lectins, C-Type; D012333:RNA, Messenger; D000099192:CD69 Antigens