PART 1: PERIPHERAL BLOOD
PARTS 2 AND 3:
BONE MARROW, BIOPSY AND TOUCH IMPRINTS
The peripheral blood smear and marrow aspirates show numerous blasts which account for 45% and 95% of nucleated cells, respectively. The bone marrow is 95% cellular with complete effacement of normal hematopoiesis which is replaced by leukemic infiltrate. The leukemic blasts are medium-sized with high N/C ratio and cup-shaped nuclei. Several small lymphoid aggregates which account for about 5% of marrow cells are also noted. The flow cytometric studies reveal a large myeloid blast population that is CD45 (dim+), CD34-, CD33+, CD117 (dim+), CD56+, CD15-, CD19- and CD14-. A second, lambda-restricted B-cell population is also present. These results are similar to previously reported acute myeloid leukemia and concurrent B-cell lymphoid neoplasm.
A small subset of patients with acute myeloid leukemia (AML) have cup-like nuclei. Several previous studies have demonstrated that AML with cup-like nuclei morphology has distinctive clinicopathologic and molecular features. They are associated with fms-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD); nucleophosmin 1 (NPM1) mutations; normal karyotype; myeloperoxidase positivity; higher D-dimer levels and loss of CD34 and HLA-DR expression. These findings suggest that AML with cup-like nuclei features may represent a distinct AML subset.
Contributed by Lin Liu, MD, PhD and Miroslav Djokic, MD