Blastic Plasmacytoid Dendritic Cell Neoplasm



Blastic Plasmacytoid Dendritic Cell Neoplasm


Kaaren K. Reichard, MD









Bone marrow aspirate smear from a patient with blastic plasmacytoid dendritic cell neoplasm shows typical lymphoblast-like cytology. This case also shows pseudopod formation.






Bone marrow core biopsy from a patient with blastic plasmacytoid dendritic cell neoplasm shows marrow effacement by a variably sized blastic neoplasm. Immunophenotypic studies reveal the cell lineage.


TERMINOLOGY


Abbreviations



  • Blastic plasmacytoid dendritic cell neoplasm (BPDCN)


Synonyms



  • CD4(+)/CD56(+) hematodermic neoplasm


  • Blastic NK-cell lymphoma


  • CD4(+)/CD56(+) lineage-negative malignancy


  • Agranular CD4(+) natural killer-cell leukemia


Definitions



  • Malignancy of plasmacytoid dendritic cells


  • Neoplasm with typical cutaneous and bone marrow involvement (“hematodermic”)


ETIOLOGY/PATHOGENESIS


Environmental Exposure



  • None clearly identified


Infectious Agents



  • No link with Epstein-Barr virus infection


Postulated Normal Cell Counterpart



  • Plasmacytoid dendritic cell



    • a.k.a. interferon-producing cell, dendritic cell type 1 (DC1)


    • a.k.a. (previously) plasmacytoid monocyte, plasmacytoid T cell


    • Produces high amounts of α-interferon


    • Innate immunity


    • Derives from either common lymphoid or myeloid precursor in bone marrow


Some Cases Associated with Myeloid Neoplasia



  • BPDCN and myelodysplasia


  • BPDCN and myelomonocytic leukemia


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Exceedingly rare


  • Age



    • Mainly adults



      • Average age range: 60-67 years


    • Children and young adults also


  • Gender



    • Male predominant; M:F ratio = 3-4:1


  • Ethnicity



    • No known ethnic predisposition


Site



  • BPDCN involves multiple tissues



    • Skin



      • > 95% of cases


      • Often initial site of disease


    • Peripheral blood and bone marrow



      • 60-90% of cases


      • May be involved at diagnosis (˜ 30-40%) or at relapse


    • Lymph nodes



      • 30-40%


Presentation



  • Skin lesions


  • Abnormal CBC


  • Circulating neoplastic cells


  • Cytopenias


  • Blastic bone lesions


Treatment



  • Options, risks, complications



    • Definitive treatment unclear with so few cases


  • Multiagent chemotherapy



    • Some advocate acute leukemia-type regimen


    • Some advocate high-grade lymphoma-type regimen



Prognosis



  • Aggressive clinical course


  • Median survival: 12-14 months


  • Most cases initially respond to multiagent chemotherapy (> 80%)


  • Subsequent relapse in treatment resistant


  • Rare reports of long-term survival


MACROSCOPIC FEATURES


General Features



  • Skin lesions


  • Splenomegaly (< 20%)


  • Hepatomegaly (< 20%)


MICROSCOPIC PATHOLOGY


Predominant Pattern/Injury Type



  • Infiltrative


Predominant Cell/Compartment Type



  • Dendritic cell

Jun 13, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Blastic Plasmacytoid Dendritic Cell Neoplasm
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