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Case 313 - Discussion

Hematopathology Case

CD20, skin biopsy CD20, bone marrow biopsy



Intravascular Large B-Cell Lymphoma

Definition and Clinical Features

  • An aggressive extranodal lymphoma with proliferation of tumor cells in small vessels, particularly capillaries
  • Rare, frequency < 1/ 1,000,000
  • Median age 67 years, no gender predilection
  • Clinical presentations:
    • Classic variant: Typically in Western countries with frequent CNS and skin involvement
    • Asian variant: Hemophagocytic syndrome, fever, hepatosplenomegaly, thrombocytopenia, bone marrow involvement; not commonly involves CNS and skin
    • Cutaneous variant: A subtype of classic variant, only skin involvement, almost exclusively female, mean age 59 years, normal platelet and leukocyte counts
  • > 90% in stage III/IV with high IPI
Morphologic Features
  • Predominantly or exclusively in small blood vessels
  • Tumor cells: large cells with centroblastic, immunoblastic, or unclassifiable appearance Frequent mitotic figures
  • May palisade along vessel lumen, mimicking angiosarcoma; or deceptively cohesive, resembling carcinoma
  • May have fibrin thrombi, hemorrhage and necrosis
  • Hemophagocytosis in the Asian variant
Immunophenotypic Features
  • Positive: CD45, pan-B markers
  • A small subset of cases express CD5 and CD10
  • Negative: CD29 (β1-integrin), CD54 (ICAM-1)
  • No association with EBV or HTLV-1