Chronic Lymphocytic Leukemia
A 77-year-old female exhibited significant atypical lymphocytosis, normocytic normochromic anemia, and severe thrombocytopenia. Flow cytometry of the immunophenotyping of the peripheral blood showed a lambda light chain restricted B-cell population, expressing CD19, CD20 (dim), CD22, CD5, CD23, CD11c, and CD200. A bone marrow aspiration and core biopsy revealed approximately 95% cellularity with marked involvement by small lymphocytes, and only occasional foci of trilineage hematopoiesis. Interphase fluorescence in situ hybridization (FISH) performed on the bone marrow aspirate revealed deletion 13q and 17p, including loss of the ATM and TP53 gene regions, respectively, and a BCL2/IGH gene fusion.