title: Atypical marginal zone hyperplasia of mucosa-associated lymphoid tissue: a reactive condition of childhood showing immunoglobulin lambda light-chain restriction.
abstract: Mucosa-associated lymphoid tissue (MALT) lymphomas usually arise at sites of acquired MALT and are uncommon in native MALT (eg, Peyer patches and tonsil). Malignancy in these low-grade lymphomas is often inferred by immunoglobulin light-chain restriction and expression of CD43; molecular genetic evidence is sought only if these are in doubt. We report 6 cases (4 tonsils, 2 appendixes) of marginal zone (MZ) hyperplasia in children aged 3 to 11 years that, despite histologic and immunophenotypic features indicative of lymphoma, were polyclonal by molecular analysis. No lymphoma-directed therapy was given and patients remain alive and well (5 cases, median follow-up 35.3 months). The involved tonsil and appendix showed florid MZ hyperplasia with prominent intraepithelial B cells (IEBCs). The MZ B cells and IEBCs showed a high-proliferation fraction and a CD20(+), CD21(+), CD27(-), immunoglobulin (Ig) superfamily receptor translocation-associated 1-positive (IRTA-1(+)), CD43(+), multiple myeloma oncogene 1 (MUM-1), IgM(+)D(+) phenotype. Polymerase chain reaction (PCR), cloning, and sequencing of rearranged IgH and Iglambda genes (whole tissue sections [6 cases]; microdissected cells [2 cases]) showed that the MZ B cells and IEBCs were polyclonal and the IgH genes nonmutated. In contrast, MZ (intraepithelial) B cells of 6 control tonsils had a similar immunophenotype, except for expression of CD27 and polytypic light chains, whereas molecular studies showed that they were polyclonal with mutated Ig genes.
authors.affiliation: Department of Histopathology, Royal Free and University College Medical School, Rockefeller Bldg, University St, London WC1E 6JJ, United Kingdom.
authors.forename: Ayoma D
authors.initials: AD
authors.lastname: Attygalle
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Liu
authors.forename: Sima
authors.initials: S
authors.lastname: Shirali
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Diss
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
authors.forename: Ahmet
authors.initials: A
authors.lastname: Dogan
authors.forename: Ming-Qing
authors.initials: MQ
authors.lastname: Du
authors.forename: Peter G
authors.initials: PG
authors.lastname: Isaacson
mesh_terms: D001065:Appendix / Q000473:pathology*; D001402:B-Lymphocytes / Q000502:physiology; D002455:Cell Division / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D015870:Gene Expression; D006801:Humans; D006965:Hyperplasia; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D016130:Immunophenotyping; D018442:Lymphoma, B-Cell, Marginal Zone / Q000276:immunology* / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D014066:Palatine Tonsil / Q000473:pathology*
chemical_list: D007146:Immunoglobulin lambda-Chains