A. Peripheral blood smear (WBC 40.49K/µL) with 76% blasts, intermediate in size with high nuclear:cytoplasmic ratios, slightly irregular nuclear contours, small nucleoli and agranular cytoplasm. Normocytic anemia with anisocytosis and slight polychromasia is present (H&E, 1000x oil).A. Peripheral blood smear (WBC 40.49K/µL) with 76% blasts, intermediate in size with high nuclear:cytoplasmic ratios, slightly irregular nuclear contours, small nucleoli and agranular cytoplasm. Normocytic anemia with anisocytosis and slight polychromasia is present (H&E, 1000x oil).
B. Bone marrow aspirate showing increased blasts with similar morphology as those present in the peripheral blood (H&E, 1000x oil).B. Bone marrow aspirate showing increased blasts with similar morphology as those present in the peripheral blood (H&E, 1000x oil).
C. Bone marrow core biopsy which is hypercellular and subtotally replaced by sheets of blasts (H&E, 40x).C. Bone marrow core biopsy which is hypercellular and subtotally replaced by sheets of blasts (H&E, 40x).
D. Bone marrow core biopsy shows atypical mononuclear cells consistent with blasts with dispersed chromatin, small nucleoli and frequent mitotic figures (H&E, 500x oil).D. Bone marrow core biopsy shows atypical mononuclear cells consistent with blasts with dispersed chromatin, small nucleoli and frequent mitotic figures (H&E, 500x oil).
E. Bone marrow core biopsy showing rare monocytic cells (dark cytoplasmic staining) and patchy, artifactual nuclear blush on the blast cells (muramidase, 500x).E. Bone marrow core biopsy showing rare monocytic cells (dark cytoplasmic staining) and patchy, artifactual nuclear blush on the blast cells (muramidase, 500x).
F. NSE cytochemistry showing nonspecific block-like staining in the leukemic blasts (NSE, 1000x oil) with diffuse cytoplasmic staining in a monocyte as a positive internal control (inset).F. NSE cytochemistry showing nonspecific block-like staining in the leukemic blasts (NSE, 1000x oil) with diffuse cytoplasmic staining in a monocyte as a positive internal control (inset).
G. Bone marrow core biopsy positive for B-lineage markers (Left – CD79a, Right – PAX5; 1000x oil)G. Bone marrow core biopsy positive for B-lineage markers (Left – CD79a, Right – PAX5; 1000x oil)
H. Partial karyogram demonstrating t(4;11)(q21;q23).H. Partial karyogram demonstrating t(4;11)(q21;q23).
I. Selected flow cytometric dot plots demonstrating limited expression of antibodies by the blasts (blasts are purple, CD45 dim).I. Selected flow cytometric dot plots demonstrating limited expression of antibodies by the blasts (blasts are purple, CD45 dim).