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Blood, 15 June 2008, Vol. 111, No. 12, pp. 5418-5419. This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Google Scholar Articles by Said, J. PubMed PubMed Citation Articles by Said, J. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  NEOPLASIA Comment on Feldman et al, page 5433 Follicular lymphomas and histiocytic/dendritic neoplasms related? Jonathan Said UNIVERSITY OF CALIFORNIA LOS ANGELES MEDICAL CENTER In this issue of Blood, Feldman and colleagues provide convincing evidence of a clonal relationship between follicular lymphoma and H/DC sarcoma, suggesting plasticity between these apparently disparate lineages with implications for transformation events in malignant lymphomas. The rarity of dendritic-cell tumors and the little that is known about their pathogenesis makes them a fascinating subject. The availability of new methodologies to confirm dendritic-cell lineage and awareness of the broadening morphologic spectrum have resulted in wider recognition of this tumor. There are no known etiologic factors, although cases with features of inflammatory pseudotumor have been associated with the Epstein-Barr virus, and there is an association with Castleman disease of the hyaline vascular type.1 In the cases associated with Castleman disease, dendritic cells proliferate outside of the follicles and form clusters and sheets, suggesting that the neoplasm has evolved from the follicles. In an earlier study, Nayer et al showed clonal cytogenetic abnormalities and Bcl2 rearrangement with t(14;18) in a case of interdigitating dendritic-cell sarcoma. 2 Now, Feldman and colleagues report on a group of patients with both follicular lymphoma and histiocytic sarcoma, including 5 derived from follicular dendritic cells and 1 interdigitating dendritic-cell sarcoma. The sarcomas were synchronous in all but 3 of the 8 tumors, which developed up to 12 years after the follicular lymphomas. In no case did the histiocytic/dendritic-cell (H/DC) tumor precede the onset of lymphoma. Molecular studies, which were performed on all 8 of the tumor pairs, provide convincing evidence of a clonal relationship between these apparently disparate neoplasms. All of the H/DC neoplasms showed t(14;18) by fluorescent in situ hybridization. Polymerase chain reaction sequencing identified identical IgH rearrangements and Bcl2 gene breakpoints in all patient tumor pairs that could be tested. View larger version (155K): [in this window] [in a new window]   Follicular dendritic-cell sarcoma with syncytial proliferation of spindle cells. Note the characteristic sprinkling of lymphocytes within the tumor. The inset shows the ultrastructural appearance of dendritic cells with villous cell processes and prominent lysosomal granules.   Plasticity between myeloid cells and dendritic cells is well known, and Paquette et al have shown that myeloid cells can be induced to differentiate into dendritic cells with interferon alpha.3 It now appears that a similar lack of lineage fidelity can occur between neoplastic lymphoid cells and H/DCs. Although this is a small group of patients, these findings have obvious implications for transforming events including clonal evolution and development of secondary neoplasms in patients with common types of low-grade lymphoma. Footnotes Conflict-of-interest disclosure: The author declares no competing financial interests. REFERENCES Chan J. Proliferative lesions of follicular dendritic cells: An overview, including a detailed account of follicular dendritic cell sarcoma, a neoplasm with many faces and uncommon etiologic associations. Adv Anat Pathol. 1997;4:387–411. Nayer H, Murphy KM, Hawkins AL, et al. Clonal cytogenetic abnormalities and BCL2 rearrangement in interdigitating dendritic cell sarcoma. Leuk Lymphoma. 2006;47:2651–2654.[CrossRef][Medline] [Order article via Infotrieve] Paquette RL, Hsu N, Said J, et al. Interferon-alpha induces dendritic cell differentiation of CML mononuclear cells in vitro and in vivo. Leukemia. 2002;16:1484–1489.[CrossRef][Medline] [Order article via Infotrieve] CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Clonally related follicular lymphomas and histiocytic/dendritic cell sarcomas: evidence for transdifferentiation of the follicular lymphoma clone Andrew L. Feldman, Daniel A. Arber, Stefania Pittaluga, Antonio Martinez, Jerome S. Burke, Mark Raffeld, Mireia Camos, Roger Warnke, and Elaine S. Jaffe Blood 2008 111: 5433-5439. [Abstract] [Full Text] [PDF] This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Google Scholar Articles by Said, J. PubMed PubMed Citation Articles by Said, J. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?

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