Burkitt leukemia with atypical morphology and subsequent therapy-related acute myeloid leukemia

Abstract

A 10-year-old previous healthy boy presented with jaw pain for several weeks. Compete blood count revealed leukocytosis (WBC 41.08 X 109/L), anemia (Hemoglobin 79 g/L) and thrombocytopenia (platelet count 50 X 109/L). Peripheral blood (PB) and bone marrow (BM) smears (Figure 1, panels A and B) showed frequent small sized blasts with high nucleus-to-cytoplasm ratio, and hand-mirror morphology. Flow cytometry analysis of BM showed 75% blasts with surface kappa-restriction, strongly positive for CD38, CD20, CD45, and negative for CD34 (Figure 1, panels C to E). The blasts were negative for CD10 and TdT. Cytogenetic study showed a complex abnormal karyotype: 46,XY,del(1)(q23),add(3)(q25),t(8;14)(q24.1;q32.3),der(13)t(1;?;13)(q23;?;q13). FISH analysis confirmed MYC gene rearrangement (Figure 1, panel F). Burkitt leukemia (BL) was diagnosed. Patient underwent chemotherapy per COG ANHL01P1 protocol and achieved complete remission. 17 months after chemotherapy, he developed thrombocytopenia and monocytosis. BM showed many immature or atypical monocytic cells (Figure 1, panel G). Cytogenetic study showed t(11;19)(q23;p13.1). FISH confirmed KMT2A rearrangement (Figure 1, panel H).