Acute Promyelocytic Leukemia Relapsing into FAB-M2 Acute Myeloid Leukemia with Trisomy 8

Acute promyelocytic leukemia was diagnosed in a 48-year-old man; the karyotype was normal, whereas reverse transcriptase polymerase chain reaction (RT-PCR) analysis identified PML/RARα chimeric transcripts of the bcr3 type. Rather unexpectedly, the patient did not respond to all-trans retinoic acid administration; he attained complete remission with conventional chemotherapy and became PML/RARα negative. Two years later, while PML/RARα negative on RT-PCR, he presented with thrombocytopenia. Bone marrow examination was compatible with myelodysplasia of the RAEB type; the karyotype was normal. Then, after 10 months, he developed overt acute myeloid leukemia with PML/RARα negative, French–American–British M2 blasts; karyotypic analysis revealed mosaicism for trisomy 8.