Nephrotic syndrome related to chronic neutrophilic leukemia.

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm. We herein describe the case of a 41-year-old woman who was admitted with nephrotic syndrome (NS) and severe neutrophilia and underwent a splenectomy due to splenomegaly. Peripheral blood tests revealed a Janus kinase 2 (JAK2) V617F mutation without the Philadelphia chromosome, BCR-ABL fusion transcripts, or FIP1 L1-platelet-derived growth factor (PDGF)a. A kidney biopsy showed focal segmental glomerulosclerosis (FSGS) with interstitial neutrophil infiltration and with a JAK2 V617F mutation. Hydroxyurea was initiated for first three months, followed by hydroxyurea plus interferon, and a subsequent improvement in leukocytosis and completely remission of FSGS-NS was immediately noted. This is the first case reported in which NS was related to CNL.