Abstract
We report an extremely rare case of acute myelomonocytic leukemia (M4) with an MLL-ELL fusion gene lacking the PML-RARα rearrangement that transformed from hypergranular acute promyelocytic leukemia (APL) without showing any karyotypic evolution. The treatment was effective with chemotherapy for M4 and idarubicin plus a cytarabine-based chemotherapy protocol without ATRA.