CSF3R and plasma cell neoplasm: There are some case reports of an association between plasma cell neoplasms and neutrophilia, however many of the cases in the literature were reported prior to the identification of the CSF3R mutation as a pathognomonic feature of CNL, and it has now been suggested that many of these cases represent plasma cell‐driven neutrophilia, possibly by the production of granulocyte colony‐stimulation factor and other cytokines by the plasma cells.8, 9, 10