Chronic Neutrophilic Leukemia with V617F JAK2 Mutation.

Chronic neutrophilic leukemia (CNL) is a rare disease grouped under World health organization classification as chronic myeloproliferative disease. It is a diagnosis of exclusion in patients with sustained mature neutrophilia and splenomegaly with no evidence of other myeloproliferative disease or reactive neutrophilia. V617F JAK 2 mutation has been described in classical myeloproliferative diseases, but its association with CNL has been reported in a few cases. Here in, we describe three cases of CNL with presence of V617F JAK 2 mutation. To distinguish CNL from secondary neutrophilia can be difficult. Detection of the V617F JAK 2 mutation in such scenario can provide a useful diagnostic test to establish the neoplastic nature of the neutrophilia.