Acute monocytic leukemia

Just as there are many different types of myeloid cells (neutrophils, red cells, monocytes, eosinophils, basophils), there are many different types of acute myeloid leukemia (AML). Two types of AML are composed almost entirely of cells of the monocytic series: acute monoblastic leukemia and acute monocytic leukemia. In both of these types of AML, at least 80% of the leukemic cells are from the monocytic series (monoblasts, promonocytes, and monocytes). In acute monoblastic leukemia, most of these cells are monoblasts, and in acute monocytic leukemia, most of these cells are promonocytes. Promonocytes have a very characteristic appearance, as shown above. They have nuclei that show a delicate folding pattern, almost like a piece of tissue paper that has been crumpled a bit. If you had a case of acute leukemia and most of the cells looked like this, you would think about acute monocytic leukemia – and you’d get an NSE to prove it.

8 Responses to Acute monocytic leukemia

  1. Jim says:

    Can you dumb down the AML designation thing? I was taught AML is acute myeloid leukemia. Now the subsets are also AML? (acute monoblastic leukemia and acute monocytic leukemia). I’m getting confused how do we differentiate the acronyms.

    M0-M7 AML?

    And who really cares about this? Heme/Oncologists? Does the patient care?

    Anyway, it seems like the FAB criteria sucks and is a burden on most oncologists. …just my opinion.

  2. admin says:

    Yes – we could dumb it down, and just call it acute myeloid leukemia, but there are subtypes of AML that do have significance for the patient. AML-M3 for example (acute promyelocytic leukemia) is composed of malignant promyelocytes. Give this patient regular old AML chemotherapy, and you will kill him or her (because the cells will burst, releasing the granules, which contain procoagulant substances – pushing the patient into DIC). AML-M4 and M5 are important to separate out because they are much more likely than other types of AML to involve extramedullary sites (like the CNS) so these patients need additional treatment. You can learn it however you like – but if you are an oncologist, you need to know it so you can treat your patient properly.

  3. dr.mohamed osman says:

    really i encourge you about this nice jop and itis very important to differentiate betweem AML subtype .. thank you again

  4. David says:

    I agree its difficult to learn but I also agree that it is essential if you want to specialise in this field. A whole battery of tests are used to supplement blood and marrow morphology to correctly identify the leukaemic subtype. This is essential to give the patient optimum treatment.

    So, its difficult but worth doing!

    Excellent image.

  5. DrPrasad says:

    Looking at the photograph some of the blasts at 3,6 & 9 CLOCK
    position have the granule in the cytoplasm while thw rest do not have.Is it the reason why they are kept under Acute myeloid leuleukemia group M4 & M5 instead of Monocytoid leukemia groups.

  6. Kristine says:

    All of the cells in this photo are actually promonocytes. These are cells that are beyond the monoblast stage but not yet mature enough to call monocytes. Some do have granules while others appear to have fewer or no visible granules. It’s really the nucleus that makes the cell a promonocyte though, not the cytoplasm. The nucleus has a characteristic folded appearance; the chromatin is fine, and it appears that the nucleus has been crumpled like tissue paper.

    Since all the cells we see in this field are promonocytes, this would be classified as an AML-M5B. Since the cells here are definitely of the monocyte lineage, they would not be called monocytoid (a term which would apply to a cell which looked like a monocyte, but was not really a monocyte).

  7. fred says:

    Why cannot a CONSISTENTLY elevated wbc (20000-60000) with a SIGNIFICANT absolute monocytosis receive a diagnosis?

  8. Kristine says:

    If the monocytes are benign, then it would just be diagnosed as a benign monocytosis (and you’d look for reasons the patient might have this, such as infection, or solid tumors). If the monocytes are malignant, then you’d have to figure out what category of disease to invoke. In acute myeloid leukemias of a monocytic nature, the monocytic cells are promonocytes or monoblasts (not mature monocytes). If there is an increase in the number of neutrophilic cells in addition to the monocytosis, you might consider chronic myelomonocytic leukemia.

Leave a Reply

Your email address will not be published. Required fields are marked *