anaplastic large cell lymphoma ALK positive


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  • Clinical

    • children, young adults
    • location: nodes, MSK, lung, liver
    • B symptoms

  • Morphology

    • hallmark cells: anaplastic cells with kidney bean nuclei
    • patterns
      • common (60%): large cells with lots of cytoplasm, eccentric nucleus, hallmark cells, architecture effacement or sinusoidal
      • lymphohistiocytic (10%): lots of reactive histiocytes, cluster around vessels
      • small cell (5-10%): smaller cells, central nucleus, fried egg appearance, hallmark cells around vessels, may have PB involvement
      • Hodgkin-like (3%): mimicks nodular sclerosis
      • Mixed (15%)

  • Stains

    • positive: ALK (nuclear and cytoplasm), CD30, EMA, at least some T markers (CD2, 4, 5), cytotoxic antigens
    • CD3 negative in > 75% of cases
    • can be null-cell type
    • negative: EBV, BCL2

  • Cytogenetics

    • t(2;5) NPM1-ALK
    • Other partners: chr 1 TPM3, inv2 ATIC, others

  • Ddx

    • CD30 negatives: ALK+ LBCL, soft tissue tumors, ALK+ systemic histiocytosis
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