Contributed by Robert Bubar, MD 
Contributed by Robert Bubar, MD
CASE PRESENTATION
A teenage girl initially presented with weight loss, itching, and easy bruising. Outpatient lab work revealed pancytopenia, and she was referred to the emergency department at her local hospital. Additional laboratory workup revealed leukopenia (WBC 2.5 x 109/L), thrombocytopenia (platelets 141 x 109/L), and 11% circulating blasts with Auer rods on peripheral smear. A bone marrow biopsy was performed which demonstrated 73% blasts on manual differential (Figure 1). Flow cytometric studies revealed an abnormal myeloid blast population with the following immunophenotype: CD34 partial positive, CD117 positive, HLA-DR positive, CD13 positive, CD33 positive, and MPO positive. Molecular testing was negative for FLT3-ITD mutation and FLT3 D835 mutation. Cytogenetic testing revealed a subset of cells harboring a t(4;5)(p16;q35) translocation that was also detected on microarray. Fluorescence in-situ hybridization for PML-RARA rearrangement was negative. A portion of the bone marrow specimen was sent for molecular testing, including a targeted myeloid next generation sequencing (NGS) panel, and the patient was started on induction chemotherapy for a presumed diagnosis of acute myeloid leukemia. NGS testing demonstrated two CEBPA gene mutations (p.K90Rfs*71 and p.T310_Q311del) (Figure 2).
