Myeloproliferative neoplasm with ABL1/ETV6 rearrangement mimics chronic myeloid leukemia and responds to tyrosine kinase inhibitors.

Myeloproliferative neoplasms (MPN) associated with ABL1-ETV6 fusions are rare and poorly characterized. To date, less than 20 cases of ABL1-ETV6+ MPN have been reported. We report a 47-year-old man who presented with MPN with clinicopathologic features resembling chronic myeloid leukemia, but there was no evidence of t(9;22)(p34.1;q11.2) or BCR-ABL1 fusion. Conventional cytogenetics and fluorescence in situ hybridization analysis showed ins(12;9)(p13;q34q34) that led to ETV6-ABL1 fusion. The patient responded well to tyrosine kinase inhibitor therapy and achieved remission for 7 years.