title: Primary mucosa-associated lymphoid tissue lymphoma of the gallbladder: report of a case harboring API2/MALT1 gene fusion.
abstract: The genetic alterations underlying extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue type are heterogeneous and show variation according to the tumor site. Here, we report a case of mucosa-associated lymphoid tissue lymphoma of the gallbladder with genetic characterization. This lymphoma, diagnosed in a 75-year-old woman who underwent cholecystectomy for suspected acute cholecystitis, presented as diffuse thickening of the gallbladder wall. The morphology was typical of mucosa-associated lymphoid tissue lymphoma, and by immunophenotype, the tumor cells were CD20+ CD5- CD10- CD23- CD43- BCL6- BCL2+ IgM+ IgD- lambda+, with moderate nuclear expression of BCL10. Interphase fluorescence in situ hybridization analysis on paraffin sections, using a fusion probe for API2/MALT1, demonstrated 2 fusion signals in most nuclei, bringing the first documentation of a t(11;18)(q21;q21) in this exceptional primary disease location.
authors.affiliation: Department of Pathology, Centre Hospitalier Universitaire du Sart Tilman, Liège, Belgium.
authors.forename: Bettina
authors.initials: B
authors.lastname: Bisig
authors.forename: Christiane
authors.initials: C
authors.lastname: Copie-Bergman
authors.forename: Maryse
authors.initials: M
authors.lastname: Baia
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaulard
authors.forename: Katty
authors.initials: K
authors.lastname: Delbecque
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Fassotte
authors.forename: Jacques
authors.initials: J
authors.lastname: Boniver
authors.forename: Laurence
authors.initials: L
authors.lastname: de Leval
mesh_terms: D000368:Aged; D002763:Cholecystectomy; D005260:Female; D005706:Gallbladder Neoplasms / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics*
chemical_list: C415943:API2-MALT1 fusion protein, human; D015514:Oncogene Proteins, Fusion