Neutrophilic progression in a case of polycytemia vera mimicking chronic neutrophilic leukemia: clinical and molecular characterization

Background: In a small subset of polycytemia vera (PV), neutrophilia not secondary to reactive conditions or treatment can develop and persist. Clinical significance and morphogenetic alterations associated with this uncommon phenomenon are not well defined. Case report: An 81-year-old Caucasian woman, affected by polycytemia vera lasting 17 years, presented in March 2012 with hyperleukocytosis, absolute neutrophilia, and thrombocytosis despite hydroxyurea treatment. All other laboratory parameters were normal, except for an increased neutrophil alkaline phosphatase and lactate dehydrogenase. Reactive neutrophilia due to infection or neoplasia have been ruled out by a total body computerized tomography scan, and by low levels of C reactive protein. Re-evaluation of bone marrow showed hypercellular smears with expansion of granulopoiesis while immature granulocytes were <10% and myeloblasts were