A case of double positive myeloproliferative neoplasm: A diagnostic and therapeutic challenge.

Chronic Myeloid Leukemia, BCR-ABL1 positive (CML) is distinct from other myeloproliferative neoplasms (MPNs) as it is positive for the Philadelphia chromosome (Ph) with presence of BCR-ABL1 translocation that makes it responsive to targeted therapy with tyrosine kinase inhibitors (TKI). Distinctly there is another group of Ph-negative myeloproliferative neoplasms as polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET) and others that harbor an activating mutation in the Janus Kinase 2 gene (JAK2), i.e., JAK2 V617F mutation. BCR-ABL1 translocation and the JAK2 V617F mutation are generally considered disease defining and mutually exclusive due to diagnostic and therapeutic implications. We hereby present a rare case of MPN with coexistent expression of BCR-ABL1 translocation and JAK2 V617F mutation thus posing a challenge in diagnosis, treatment, and follow-up.