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Case 94 - Discussion

Hematopathology Case


  Flow Cytometry:

      CD45  Dim

      CD4   +

      CD13  +

      CD24  +

      CD34  +

      CD61  +


         46, XX, t(1;22;10)(p13;q13;q11.2)


Acute Megakaryoblastic Leukemia with t(1;22)(p13;q13); (RBM15-MKL1)

  •  Almost exclusively in infants, medium age 4 months, with no history of Down syndrome

  • Commonly hepatosplenomegaly or other organomegaly

  • Morphology:

    • Cytology of blasts: medium-sized or large, rounded nuclei with fine reticular chromatin, visible nucleoli, agranular basophilic cytoplasm, and occasional cytoplasmic blebbing

    • Lack of overt multilineage dysplasia

    • Typical collagen fibrosis of bone marrow

  • Negative: CD45, CD34 and HLA-DR

  • Positive: CD13, CD33, CD41, CD42, CD61, CD43 and vWF

  • DDX: small blue round cell tumors, including neuroblastoma and nephroblastoma ( 3-4 years of age, but rarely with bone metastasis)

  • Relatively good prognosis