Co-occurrence of mutation and translocation in chronic myeloproliferative neoplasms: a potentially confounding genetic combination.

Myeloproliferative neoplasms (MPNs) are classified into Philadelphia (Ph) chromosome-positive chronic myeloid leukemia (CML) and Ph-negative MPNs. translocation is the key genetic event of CML, whereas mutations are molecular aberrations of Ph-negative MPNs. Despite initially considered mutually exclusive genetic aberrations, the co-occurrence of and has been reported in a limited number of cases. The two genetic alterations may be identified either at the same time or aberration may be detected in patients with a previous CML treated with tyrosine kinase inhibitors or, finally, translocation occurs in patients with a history of -positive MPN. This combination of genomic alterations is potentially confounding with clinical manifestations often misinterpreted either as disease progression or drug resistance, therefore leading to inappropriate patient's treatment. Our systematic review aims to improve hematologist and pathologist knowledge on this rare subset of patients. Starting from the presentation of two additional cases from our routine daily practice, we focus mainly on clinical, laboratory, and bone marrow histological findings, which may represent useful clues of and co-occurrence. The interaction between and clones during the disease course as well as therapy and outcome are presented.