title: CD123-positive plasmacytoid dendritic cells in primary cutaneous marginal zone B-cell lymphoma: diagnostic and pathogenetic implications.
abstract: The histogenesis of primary cutaneous marginal zone B-cell lymphoma (PCMZL) has not yet been clarified. Plasma-cytoid dendritic cells (PDC) play a crucial role in the initiation of immune responses and activation of T-cells and B-cells. We analyzed the presence of PDC by immunohistochemistry in various forms of primary cutaneous B-cell lymphomas and in B-cell pseudolymphomas. Clusters of CD123+PDC were observed in all PCMZL (23 of 23 cases; 100%) and in two-thirds of cutaneous B-cell pseudolymphomas (14 of 22; 64%), but only in a minority of primary cutaneous follicle center lymphoma (4 of 31; 13%) and not in primary cutaneous diffuse large B-cell lymphoma, leg type. CD123+ PDC clusters were found in close proximity to monoclonal plasma cells and T-cells and were already present at high numbers in early lesions and initial recurrences of PCMZL. In conclusion, the detection of larger clusters of PDC in PCMZL provides a useful adjunctive diagnostic marker and suggests a pathogenetically relevant role of these cells in PCMZL. Furthermore, the occurrence of PDC could explain the high number of T-cells typically found in PCMZL. We propose considering PCMZL as a unique and potentially antigen-driven neoplasm with PDC, T-cells, and B-cells as the constitutive tumor components.
authors.affiliation: Dermatopathologie, Friedrichshafen, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
authors.forename: Helmut
authors.initials: H
authors.lastname: Kerl
authors.forename: Monique C
authors.initials: MC
authors.lastname: Pfaltz
authors.forename: Werner
authors.initials: W
authors.lastname: Kempf
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002999:Clone Cells; D003713:Dendritic Cells / Q000378:metabolism* / Q000473:pathology; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D006801:Humans; D007124:Immunoenzyme Techniques; D007147:Immunoglobulin Light Chains / Q000378:metabolism; D053650:Interleukin-3 Receptor alpha Subunit / Q000378:metabolism*; D008198:Lymph Nodes / Q000473:pathology; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008224:Lymphoma, Follicular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010950:Plasma Cells / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C115022:IL3RA protein, human; D007147:Immunoglobulin Light Chains; D053650:Interleukin-3 Receptor alpha Subunit