While an association between CNL and plasma cell dyscrasia has been reported [6], a recent study found that plasma cell dyscrasia‐derived G‐CSF could induce CNL‐like neutrophilia without a CSF3R mutation [4], suggesting that when clinicians diagnose CNL in a patient with plasma cell dyscrasia, caution should be exercised to avoid misdiagnosis. The gene discussed is CSF3; the disease is chronic neutrophilic leukemia.