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. 2025 Jun 24.
doi: 10.1007/s00428-025-04114-5. Online ahead of print.

Plasmacytoid dendritic cell proliferations, malignant histiocytic (macrophage/dendritic cell) neoplasms and follicular dendritic cell neoplasms: report from the 2024 Joint CSHP/EA4HP/SH workshop

Caoimhe Egan  1 , Sophie Song  2 , Wei-Ping Liu  3 , Zhe Wang  4 , Wenbin Xiao  5 , John K C Chan  6 , Stefan Dirnhofer  7 , Falko Fend  8 , John R Goodlad  9 , Xiaoqiu Li  10 , Robert Lorsbach  11 , Jean-Francois Emile  12
Affiliations

Plasmacytoid dendritic cell proliferations, malignant histiocytic (macrophage/dendritic cell) neoplasms and follicular dendritic cell neoplasms: report from the 2024 Joint CSHP/EA4HP/SH workshop

Caoimhe Egan et al. Virchows Arch. .

Abstract

Histiocytic and dendritic cell neoplasms of hematopoietic origin are derived from or show differentiation towards the cells of the mononuclear phagocyte system. Plasmacytoid dendritic cell proliferations/neoplasms include mature plasmacytoid dendritic cell proliferations identified in the context of a defined myeloid neoplasm and blastic plasmacytoid dendritic cell neoplasm, an aggressive tumor with a poor outcome. Malignant histiocytic (macrophage/dendritic cell) neoplasms occur de novo or in the setting of another hematological malignancy, typically "transdifferentiated" from associated lymphoid neoplasia. Recurrent alterations in the MAPK pathway have been shown to have a key role in their pathogenesis. Neoplasms derived from follicular dendritic cells and fibroblastic reticular cells originate from a mesenchymal precursor. The major entities in this group include follicular dendritic sarcoma, which has recently been shown to harbor recurrent alterations in NF-κB pathway genes, and EBV positive inflammatory follicular dendritic cell sarcoma/tumor, a rare lesion with an inflammatory pseudotumor-like morphology and association with EBV infection. At the joint Workshop of the Chinese Society of Hematopathology (CSHP), the European Association for Haematopathology (EA4HP) and the Society for Hematopathology (SH) on histiocytic/dendritic cell proliferations, neoplasms, and their mimics in Hefei, China, April 2024, there were 16 cases submitted to session 3 on plasmacytoid dendritic cell proliferations and neoplasms, and a total of 42 submissions to session 4 on malignant histiocytic and dendritic cell neoplasms, including stroma-derived neoplasms. A summary of the findings and conclusions arising from discussion of the workshop cases are presented in this report.

Keywords: Blastic plasmacytoid dendritic cell neoplasm; Follicular dendritic cell sarcoma; Histiocytic sarcoma; Joint workshop.

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Conflict of interest statement

Declarations. Ethics approval: The authors confirm that ethical standards have been observed in this work. Conflict of Interest: The authors declare no competing interests.

References

    1. WHO Classification of Tumours Editorial Board (2024) Haematolymphoid tumours. International Agency for Research on Cancer, Lyon (France)
    1. Alaggio R, Amador C, Anagnostopoulos I, Attygalle AD, Araujo IBO, Berti E, Bhagat G, Borges AM, Boyer D, Calaminici M, Chadburn A, Chan JKC, Cheuk W, Chng WJ, Choi JK, Chuang SS, Coupland SE, Czader M, Dave SS, de Jong D, Du MQ, Elenitoba-Johnson KS, Ferry J, Geyer J, Gratzinger D, Guitart J, Gujral S, Harris M, Harrison CJ, Hartmann S, Hochhaus A, Jansen PM, Karube K, Kempf W, Khoury J, Kimura H, Klapper W, Kovach AE, Kumar S, Lazar AJ, Lazzi S, Leoncini L, Leung N, Leventaki V, Li XQ, Lim MS, Liu WP, Louissaint A Jr, Marcogliese A, Medeiros LJ, Michal M, Miranda RN, Mitteldorf C, Montes-Moreno S, Morice W, Nardi V, Naresh KN, Natkunam Y, Ng SB, Oschlies I, Ott G, Parrens M, Pulitzer M, Rajkumar SV, Rawstron AC, Rech K, Rosenwald A, Said J, Sarkozy C, Sayed S, Saygin C, Schuh A, Sewell W, Siebert R, Sohani AR, Tooze R, Traverse-Glehen A, Vega F, Vergier B, Wechalekar AD, Wood B, Xerri L, Xiao W (2022) The 5th edition of the World Health Organization classification of haematolymphoid tumours: lymphoid neoplasms. Leukemia 36:1720–1748. https://doi.org/10.1038/s41375-022-01620-2
    1. Arber DA, Orazi A, Hasserjian RP, Borowitz MJ, Calvo KR, Kvasnicka HM, Wang SA, Bagg A, Barbui T, Branford S, Bueso-Ramos CE, Cortes JE, Dal Cin P, DiNardo CD, Dombret H, Duncavage EJ, Ebert BL, Estey EH, Facchetti F, Foucar K, Gangat N, Gianelli U, Godley LA, Gökbuget N, Gotlib J, Hellström-Lindberg E, Hobbs GS, Hoffman R, Jabbour EJ, Kiladjian JJ, Larson RA, Le Beau MM, Loh ML, Löwenberg B, Macintyre E, Malcovati L, Mullighan CG, Niemeyer C, Odenike OM, Ogawa S, Orfao A, Papaemmanuil E, Passamonti F, Porkka K, Pui CH, Radich JP, Reiter A, Rozman M, Rudelius M, Savona MR, Schiffer CA, Schmitt-Graeff A, Shimamura A, Sierra J, Stock WA, Stone RM, Tallman MS, Thiele J, Tien HF, Tzankov A, Vannucchi AM, Vyas P, Wei AH, Weinberg OK, Wierzbowska A, Cazzola M, Döhner H, Tefferi A (2022) International Consensus Classification of myeloid neoplasms and acute leukemias: integrating morphologic, clinical, and genomic data. Blood 140:1200–1228. https://doi.org/10.1182/blood.2022015850
    1. Bigenwald CD, Roos-Weil D, Pages A, Helias-Rodzewicz Z, Copie-Bergman C, Nashvi M, Khneisser P, Parrens MC, Traverse-Glehen A, Ray-Coquard I, Ysebaert L, Marchand T, Razanamahery J, Charlotte F, Neel A, Damaj G, Dion J, Nazal-Traissac EM, Tardy S, Salmeron G, Monjanel H, Iobaih A, Heritier S, Haroche J Md P, Donadieu J, Emile JF (2025) Characterization and treatment outcomes of malignant histiocytoses in a retrospective series of 141 cases in France. Blood Adv. https://doi.org/10.1182/bloodadvances.2024015208
    1. Brunner P, Rufle A, Dirnhofer S, Lohri A, Willi N, Cathomas G, Tzankov A, Juskevicius D (2014) Follicular lymphoma transformation into histiocytic sarcoma: indications for a common neoplastic progenitor. Leukemia 28:1937–1940. https://doi.org/10.1038/leu.2014.167 - DOI - PubMed

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