Decitabine treatment for an unusual case of atypical chronic myeloid leukemia (aCML) with a concomitant chronic lymphocytic leukemia (CLL)

Atypical chronic myeloid leukemia (aCML) is a rare hematological malignancy with dismal prognosis, usually being reported as isolated disease or in association with other myeloid neoplasms. Treatment strategies used for MDS and MPN, as hypomethylating agents (HMA) or kinase inhibitors, may be considered although experience is limited. We biologically studied an old patient affected by aCML unusually mutated for both SETBP1 and CSF3R, with concomitant chronic lymphocytic leukemia (CLL). Decitabine (DCA) therapy carried complete response after fourth cycle and was complicated by hematological toxicities and infections mainly due to the old age and the CLL-related immune deficit. Our case confirms DCA effectiveness in aCML and shows for the first time its safety even in older patients with concomitant lymphoproliferative disorders.