Persistent Hypoplastic Acute Promyelocytic Leukemia with a Novel Chromosomal Abnormality of 46, XY, t(15;17), t(9;11)(q13;p13)

Abstract

　 A diagnosis of acute promyelocytic leukemia (APL) is usually made when normal hematopoietic cells are substituted by APL cells. We encountered a unique APL patient who presented with persistent hypoplastic features of APL. An 84-year-old man presented with leukopenia (2.2 × 10⁹/L) and anemia (Hb 12.5 g/dL). Five months later, the bone marrow (BM) was hypoplastic with a normal proportion of blasts and promyelocytes (5.2%), although the latter cells were hypergranular. The karyotype of BM cells was 46, XY, t(15;17)(q22;q12), t(9;11)(q13;p13). Two months later, the BM remained hypoplastic with 8.5% hypergranular promyelocytes, some of which contained faggot of Auer rods. RT-PCR examination yielded the PML-RARα transcript, and its sequencing revealed the breakpoint of PML to be bcr2. The patient was treated with all-trans retinoic acid under a diagnosis of APL with improvement of the bicytopenia. FISH analysis of BM cells yielded a negative result regarding t(15;17), although RT-PCR was positive for PML-RARα mRNA. Six months later, APL recurred with the same karyotypic abnormalities and therapeutic resistance, and the patient died of pneumonia. A persistent hypoplastic state of APL may be a rare event, and the association of t(15;17) and t(9;11) is novel. [J Clin Exp Hematop 55(2) : 71-76, 2015]