title: Multifocal mantle cell lymphoma in situ in the setting of a composite lymphoma.
abstract: OBJECTIVE
  Mantle cell lymphoma in situ (MCLIS) consists of immunophenotypically defined but histologically inapparent neoplastic cells restricted to narrow mantle zones, without expansion or invasion beyond the mantle zone. We report a unique case of MCLIS associated with a much more manifest nodal marginal zone lymphoma (MZL) in an inguinal lymph node, porta hepatis lymph node, and bone marrow.
  
  
  METHODS
  Biopsies from all three locations were evaluated using standard H&E-stained sections, immunohistochemistry, flow cytometry, metaphase cytogenetics, and/or fluorescence in situ hybridization (FISH).
  
  
  RESULTS
  This case is unique for three reasons. First, the histologically covert mantle cell lymphoma was multifocal, detected in all three locations using one or more of flow cytometry, immunohistochemistry, cytogenetics, and FISH. Second, the MCLIS was always accompanied by a more histologically dominant MZL. Third, where evaluable, it did not grow in an appreciable mantle zone distribution, presumably due to destruction of the normal nodal architecture by the neoplastic MZL cells and the resulting absence of recognizable follicles and mantle zones.
  
  
  CONCLUSIONS
  This unique case provides new insight into the pathogenesis of MCLIS.
authors.affiliation: From the Department of Pathology and Laboratory Medicine, Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, and.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sloan
authors.affiliation: From the Department of Pathology and Laboratory Medicine, Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, and.
authors.forename: Qun-Bin
authors.initials: QB
authors.lastname: Xiong
authors.affiliation: From the Department of Pathology and Laboratory Medicine, Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, and.
authors.forename: Anne
authors.initials: A
authors.lastname: Crivaro
authors.affiliation: St Luke's Hospital at St Luke's University Health Network, Allentown, PA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Steinman
authors.affiliation: From the Department of Pathology and Laboratory Medicine, Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, and adambagg@mail.med.upenn.edu.
authors.forename: Adam
authors.initials: A
authors.lastname: Bagg
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D058617:Composite Lymphoma / Q000473:pathology*; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D008198:Lymph Nodes / Q000473:pathology; D018442:Lymphoma, B-Cell, Marginal Zone / Q000473:pathology*; D020522:Lymphoma, Mantle-Cell / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor
keywords: Composite lymphoma; Mantle cell lymphoma in situ; Marginal zone lymphoma