The discovery of key driver mutations in the colony-stimulating-factor-3 receptor (<i>CSF3R</i>) gene resulted in the updated World Health Organization (WHO) diagnostic criteria in 2016. A significant number of CNL cases have been associated with plasma cell dyscrasias, predominantly multiple myeloma (MM) and monoclonal gammopathy of unknown significance (MGUS). Here, CSF3R is linked to plasma cell myeloma.