Page 169 - Clinical Hematology Atlas

CHAPTER 15 ACUTE MYELOID LEUKEMIA 153

ACUTE PROMYELOCYTIC LEUKEMIA—MICROGRANULAR VARIANT

A B
FIGURE 15–5A Peripheral blood (31000). FIGURE 15–5B Bone marrow (3500).

MORPHOLOGY
Peripheral Blood: White blood cell count markedly
elevated, deeply notched nuclei

Cytoplasm may appear agranular because of small
size of granules, which are evident with elec-
tron microscopy
Bone Marrow: Agranular promyelocytes, with
deeply notched nuclei
CYTOCHEMISTRY
Myeloperoxidase: strongly positive (see Figure 15-2, E)
Sudan Black B: strongly positive (see Figure 15-2, F)
GENETICS
t(15;17) is sufficient for diagnosis as AML with
recurrent genetic abnormalities regardless of blast/
promyelocyte count.
IMMUNOPHENOTYPE
CD13 , CD33 , CD34 , HLA-DR , CD64 , C
1
2
2
6
1
CD117 6 FIGURE 15–5C Bone marrow (31000).
NOTE: Microgranular promyelocytes can be confused
morphologically with monocyte precursors.