| | BM studies | APL diagnosis | AMML diagnosis |
| | Flow cytometry | CD34+, CD33+, CD117+, CD38+, and HLA-DR in majority of blasts. | Flow cytometry analysis of the peripheral blood revealed a population of immature myeloid and monocytic lineage cells accounting for 28% of the total cells with the following immunophenotypes: CD34±, CD117+, CD13+, CD33+, CD15 heterogeneous, CD64 heterogeneous, CD14−, CD7−, CD2−, CD56−, and HLA-DRlo. The monocytic lineage showed an increased population of immature cells (48% of cells CD64+, CD14±, CD33+, and HLA-DRlo, with heterogeneous expression of CD117, CD13, and CD15). |
| | Morphological description | (i) Hypercellular marrow, >95% cellularity, and mostly replaced by leukemic infiltrates. Cytoplasmic granules were noticed in subsets of blasts. A small subset of blasts had cytoplasmic hypergranulation with rare Auer rods present. Scattered blasts also show bilobed nuclear morphology.
Examination of the clot section and core biopsy showed hypercellular marrow (near 100%), replaced by sheets of immature cells. Subsets of the immature cells showed morphologic features of promyelocytes. No residual hematopoiesis was noted.
(ii) These findings were consisted with APL, hypogranular type. | (i) Hypercellular (90%) marrow with blasts occupying in excess of 90% of the marrow space. The cellular elements were almost exclusively made up of blasts (>90%).
No blasts with APL morphology were noted. Some of the blasts had round nucleus with fine chromatin and moderate cytoplasm (myeloid blasts) and others with more irregular and folded nuclei, fine chromatin, and abundant cytoplasm. Some blasts contained Auer rods.
(ii) Overall, the BM biopsy was consistent with acute myeloid leukemia with myelomonocytic phenotype. |
| | Cytogenetics | The t (15;17) was detected in 95.5% of analyzed cells. | Karyotype: 46, XY[20]. FISH analysis for PML/RARA translocation was normal. |
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