M1: (Acute minimally differentiated primitive granulocytic leukemia) is characterized by proliferation of undifferentiated or hypodifferentiated primitive granulocytes, which are divided into type I and type II. Type I cells have no granules in the cytoplasm; type II cells contain a few asplenophilic granules or Aoer vesicles in the cytoplasm. Primitive granulocytes type I + type II ≥ 90%, early juvenile ~ mature granulocytes, monocytes in less than 10%.
M2: (acute partially differentiated primitive granulocytic leukemia) is subdivided into 2 subtypes.
(1) M2a, with >30% primitive granulocytes and 10% monocytes in the bone marrow; (2) M2b, with a marked increase in abnormal primitive and early juvenile granulocytes in the bone marrow, dominated by abnormal neutrophil proliferation, with >30% of such cells.
M3: (acute promyelocytic leukemia) with abnormal promyelocytic proliferation, often >30%, divided into 2 subtypes, M3a for coarse granular type, M3b for fine granular type.
M4: (acute granulocytic and monocytic leukemia) This type has different proportions of granulocytes and monocytes in the bone marrow and peripheral blood, and is divided into 4 subtypes: ①M4a with predominantly primitive and early granulocyte proliferation, with >20% primitive, young monocytes and monocytes; ②M4b with predominantly primitive, young monocytes and monocytes proliferation, with >20% primitive and young granulocytes; ③M4c with both granulocytes and monocytes (3) M4c primitive cells have both granulocyte and monocyte lineage morphological features > 30%; (4) M4eo in addition to the above features, there are eosinophilic granules thick and round, darker coloring eosinophils accounted for 5%-30%.
M5: (acute monocytic leukemia) bone marrow mononuclear lineage cells ≥ 80%, including primitive monocytes, naive monocytes and mature monocytes are divided into 2 subtypes.
①M5a (undifferentiated type) primitive monocytes >80%.
②M5b (partially differentiated type) primitive and naive monocytes >30%, primitive monocytes 50%, primitive granulocytes or proto-monocytes >30%, primitive granulocytes or proto-monocytes 75% in blood film.
M7: (acute megakaryocytic leukemia) primitive naïve megakaryocytes ≥ 30% in bone marrow or peripheral blood, divided into 2 types.
(1) Undifferentiated type, with >30% primitive megakaryocytes in bone marrow.
②Differentiated type, with predominantly monocytic and multicytic pathological megakaryocytes in bone marrow and external blood.