First reported case of aplastic anemia occurring in a patient after acute promyelocytic leukemia in remission.

A 32-year-old Hispanic male with a history of acute pro myelocytic leukemia (APL) in complete remission presented with increasing fatigue and mild dyspnea. His previous diagnosis of APL was made 2 years ago (Figure 1). Cytogenetic evaluation at the time of diagnosis demonstrated the presence of a reciprocal translocation between chromosomes 15 and 17, t(15;17), and the promyelocytic/retinoic acid receptor (PML/RAR) alpha gene rearrangement by reverse transcriptase polymerase chain reaction (RT-PCR). Complete remission was achieved after induction therapy with all-transretinoic acid (ATRA) and idarubicin. Three cycles of consolidation treatment were performed with ATRA, idarubicin, and mitoxantrone, with subsequent maintenance therapy on 6-mercaptopurine, methotrexate, and ATRA. After completing 2 years of maintenance therapy, the patient felt well, had normal blood counts, and peripheral blood RT-PCR was negative for PML/RAR alpha. Approximately 7 months after completion of chemotherapy, the patient presented with fatigue and shortness of breath. He developed pancytopenia with a white blood cell (WBC) count of 2.1 X 109/L, hemoglobin of 12.6 g/dL, and platelets of 50 X 109/L. His physical exam at the time was unremarkable without evidence of splenomegaly. Bone marrow biopsy revealed hypoplasia (Figure 2), PCR of the peripheral blood was negative for PML/RAR alpha, and flow cytometry revealed expression of human leukocyte antigens (HLA)-DR and CD34, providing evidence against APL. There was concern of