WHO 2016 Prefibrotic Myelofibrosis in the Patients With WHO 2008 Essential Thrombocythemia

Abstract

According to newly defined features of bone marrow (BM) histology, some of the patients who were previously diagnosed with essential thrombocythemia (ET) were accepted as early/prefibrotic PMF in recent publications. The aim of this study was to explore actual rate of pre-PMF according to the 2016 revised WHO criteria. Demographic characteristics of 160 patients diagnosed with ET between 2000-2017; laboratory values; cytogenetic profile; the treatments using; disease-related thromboembolic complications; progression of the disease to MF and AML; mortality rates and cause were recorded retrospectively. The diagnosis of pre-PMF or ET was confirmed by BM morphology and clinical follow-up. BM biopsy samples obtained during the initial diagnosis were available in 107 cases. 53 cases with inaccessible BM biopsies were excluded from the study. The distribution of female/male in cases of ET was 46/28. The incidence of progression to AML was higher in pre-PMF patients. (Progression to AML: PMF 15.15%; ET 4.05%; p= 0.044). The mean duration of progression-free survival in patients with progression to AML or PMF in pre-PMF patients was 52.1 +/- 7.37 months; ET was 62.44 +/- 10.20 months. Approximately 30% of patients previously diagnosed with ET consisted of pre-PMF patients. Anemia, high LDH level, and splenomegaly are parameters that can be used in the differential diagnosis of PMF.