Brock J. Oliverio, Patricia A. Canfield, Sharon L. Wenger
During preoperative evaluation for bilateral knee replacements, a 53-year old Caucasian female was found to have a white blood cell count of 21.3 Thou/uL (3.5 – 11 Thou/uL). The patient's hemoglobin was just below the reference range at 11.1 g/dL (11.2 -15.2 g/dL), but the platelet count was markedly decreased at 22 Thou/uL (140-450 Thou/uL). Flow cytometry was performed on the peripheral blood that showed 64% blasts expressing CD19, CD20, CD22, CD10, HLA-DR, and TdT without expression of CD3, CD5, surface kappa light chain, surface lamba light chain and myeloperoxidase. Immunohistochemical (IHC) staining on the bone marrow biopsy with corresponding markers (note: only CD19 is not available for IHC staining) showed the same immunophenotype with >90% of marrow cells consistent with lymphoblasts. The cells themselves were intermediate sized blast-like cells with scant cytoplasm, round or convoluted nuclei, fine chromatin, indistinct nucleoli, and frequent mitoses. Karyotyping (Figure 1)and fluorescent in situ hybridization (FISH) analysis for t(9;22) was performed on the peripheral blood and showed the following (Figure 2):
 Figure 1
Patient karyotype using G-banding.
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 Figure 2
Patient blood cell with FISH probe for t(9;22).
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