Metamyelocytes

Appearance:

Metamyelocytes are the stage of myelopoiesis before band granulocytes. A metamyelocyte has a kidney-shaped nucleus, the indentation of which does not go past one third of the transverse diameter of the nucleus. The cytoplasm resembles that of mature granulocytes. Metamyelocytes form the postmitotic pool; this means that they are no longer able to divide.

Occurrence:
- In all myeloproliferative neoplams, in particular in chronic myelocytic leukemia and myelofibrosis.
- In severe infections with a shift to the left (leukemoid reaction).
- In abnormalities of the bone marrow blood barrier.