#00063964

A 60-year-old female without significant medical history who presented with easy bruising, gum bleeding, and new onset back pain and clinical findings consistent with DIC. CBC revealed marked thrombocytopenia (platelets 29 k/mcL), anemia (Hb 7.5 g/dL), and a WBC of 10.21 k/mcL (with differential count showing 45% blasts). The bone marrow aspirate was hypercellular and increased blasts were found (83%), The blasts exhibited erythrophagocytosis (Figure 1a-d, ×100). Flow cytometry identified aberrant myeloid blasts (~68% total events) with myelomonocytic differentiation. Karyotyping revealed t(8;16)(p11.2;p13.3). NGS testing for RUNX1, IDH1/2, FLT3 (ITD and TKD) mutations were negative. The patient was treated with cytarabine/daunorubicin and died 67 days after presentation not having achieved remission.

The unique cytogenetic findings seen in this patient was t(8;16)(p11.2;p13.3) (This is a translocation of KAT6A on chr8 to CREBBP on chr16). This is a rare abnormality (<1% of AML), with bimodal distribution median ages 1.2 and 59.4 years and female predominance. Patients may have acute monoblastic/monocytic leukemia (M4/M5). ~75% of cases have erythrophagocytosis, 30% leukemia cutis, and ~40% DIC. The presence of promyeloblast-like cells may mimic APL.