Blast phase of essential thrombocythemia: A single center study (pages 641–644)

摘要

Blast phase (BP) may occur as a late event in essential thrombocythemia (ET). This study includesn19 patients with post-ET BP diagnosed and followed in a single institution. At BP, 63% of patients hadnleukocytosis (white blood cell count >10 3 109/L), 74% had anemia (hemoglobin value <10 g/dL), 74% hadnthrombocytopenia (platelet count <100 3 109/L), and 84% were over 65 years of age. Cytogenetic analysisnwas available in 10 patients: six had karyotype aberrations. According to cytogenetic-based risk stratificationnof de novo acute leukemia (AL), all patients had an unfavorable profile. JAK2 (V617F) mutational statusnwas evaluated in five patients. In two of them, the JAK2 mutation was undetectable in blast cells (one withnJAK2-positive ET), whereas in three both granulocytes and blast cells displayed the mutation. Treatment ofnBP was patient-based according to the performance status and co-morbidities and consisted of palliation inn14 patients, and of induction of remission in five. Median survival was 2.3 months (range 0.2–22.3),nirrespective of the treatment received. In conclusion, this study indicates that AL evolved from ET hasnunfavorable clinical and biological features. JAK2 (V617F)-positive ET may evolve in few instances intonJAK2-negative leukemia.