How do you differentiate between AML-M4 and AML-M5?

I know that both can contain monoblasts and myeloblasts. Is the difference have to do with the percent of monoblasts? Thanks.


Thank you for that wikipedia entry...I already know what you told me, but thanks. Anyone else?

1 Answer

  • fss
    Lv 4
    1 decade ago
    Favorite Answer


    Acute myelomonocytic leukemia (AMMoL) is a form of acute myeloid leukemia that involves a proliferation of CFU-GM myeloblasts and monoblasts.

    It is classified under "M4" in the French-American-British classification.


    Acute monocytic leukemia (AMoL, or AML-M5) is considered a type of acute myeloid leukemia.

    In order to fulfill World Health Organization (WHO) criteria for AML-5, a patient must have greater than 20% blasts in the bone marrow, and of these, greater than 80% must be of the monocytic lineage. A further subclassification (M5a versus M5b) is made depending on whether the monocytic cells are predominantly monoblasts (>80%) (acute monoblastic leukemia) or a mixture of monoblasts and promonocytes (<80% blasts). Monoblasts can be distinguished by having a roughly circular nucleus, delicate lacy chromatin, and abundant, often basophilic cytoplasm. These cells may also have pseudopods. By contrast, promonocytes have a more convoluted nucleus, and their cytoplasm may contain metachromatic granules.

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