Bone Marrow Diagnosis of Leukemia, May 11, 2003

Bone Marrow Diagnosis of Leukemia, May 11, 2003

Leukemia is divided into acute lymphoblastic leukemia (ALL) and acute non-lymphocytic leukemia (ANLL).

1. ANLL

(1) M1 (undifferentiated type): Blast cells account for ≥90%, promyelocytes are rare, metamyelocytes and below are absent, erythroid and megakaryocytic lines are suppressed, and Auer rods are visible.

(2) M2 (partially differentiated type): M2a: Blast cells make up 30%–90%, promyelocytes and below account for 10%, monocytes account for 20%, and Auer rods are visible; M2b: Blast cells and promyelocytes account for 30%–90%, total cell count is unclear, with a predominance of increased promyelocytes, nucleoli are present, nuclear-cytoplasmic differentiation is imbalanced, and Auer rods are visible.

(3) M3 (early promyelocytic type): Abnormally increased granular early promyelocytes account for 30%, and Auer rods are visible. M3a: Granules are coarse (aniline blue staining); M3b: Granules are fine.

(4) M4 (granulocyte-monocyte type): Blast cells plus early myelocytes >20%, blast cells plus early monocytes >20%. M4a: Granulocytic predominance; M4b: Monocytic predominance; M4c: Cells exhibit morphological changes characteristic of both the blast cell lineage and the monocyte lineage; M4d: Large eosinophilic granules and large basophilic granules.

(5) M5 (acute multinucleated leukemia): Monocytic predominance, Auer rods are visible, and erythroid, granulocytic, and megakaryocytic lines are all suppressed. M5a (undifferentiated type): Blast cells account for ≥80%; M5b (partially differentiated type): Blast cells and early monocytes account for 30%–80%.

(6) M6 (erythroleukemia): Erythroid line accounts for 50%, granulocytic line accounts for 30%.

(7) M7 (acute megakaryocytic leukemia): Blast cells account for 30%, while erythroid and granulocytic lines are relatively suppressed.

2. ALL

(1) L1: Increased number of primitive and immature lymphocytes, predominantly small lymphocytes.

(2) L2: Lymphocytes vary in size.

(3) L3: Predominantly large lymphocytes.

The identification of these cell types can generally be confirmed, but those lacking typical features require oxidative staining for differential diagnosis.

A. Peroxidase and Sudan Black staining: Acute granulocytic leukemia shows strong positivity, acute lymphocytic leukemia shows negative results, and acute monocytic leukemia shows positive or weakly positive results.

B. Glycogen staining: Acute lymphocytic leukemia shows strong positivity, while acute granulocytic leukemia and monocytic leukemia show weak positivity.

C. Nonspecific lipase staining: Acute monocytic leukemia shows strong positivity, while acute granulocytic leukemia shows weak positivity.