MSH: A rare myeloproliferative disorder that is characterized by a sustained, mature neutrophilic leukocytosis. No monocytosis, EOSINOPHILIA, or basophilia is present, nor is there a PHILADELPHIA CHROMOSOME or bcr-abl fusion gene (GENES, ABL).,NCI: A disease in which too many neutrophils (a type of white blood cell) are found in the blood. The extra neutrophils may cause the spleen and liver to become enlarged. Chronic neutrophilic leukemia may stay the same for many years or it may progress quickly to acute leukemia.,NCI: A rare chronic myeloproliferative neoplasm characterised by neutrophilic leukocytosis. There is no detectable Philadelphia chromosome or BCR/ABL fusion gene.