A CALR Mutation Preceding BCR-ABL1 in an Atypical Myeloproliferative Neoplasm

A case is described in which a patient with chronic myeloid leukemia associated with thrombocytosis was shown to have a CALR mutation as an initial genetic change and BCR–ABL1 translocation as a secondary event leading to a clinically unusual myeloproliferative neoplasm.