[Allogeneic hematopoietic stem cell transplantation for the treatment of acute myeloid leukemia with primary thrombocytosis: three cases report and literatures review].

Objective: To investigate the characteristics of the essential thrombocythemia (ET) cases transformed to the acute myeloid leukemia (AML) and the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of this disease. Methods: The clinical and laboratory characteristics of 3 ET cases before and after transformation and after allo-HSCT were retrospectively analyzed, meanwhile the related literatures were reviewed and discussed. Results: Case 1 was a male patient of 44 years old, whose PLT was 500×10(9)/L when firstly diagnosed ET. After 3 years the disease progressed into myelodysplastic syndrome (MDS) while WT1 expression increased from 77 (first visit) to 13 171 copies/10 000 ABL copies, at the same time chromosome changed dramatically. During the period of decitabine treatment the disease processed into AML. Case 2 was a male of 58 years old whose PLT was 2 100×10(9)/L when firstly diagnosed ET. The disease progressed to AML after 9 years, whose WT1 expression increased from 130 (first visit) to 3 222 copies/10 000 ABL copies, and he relapsed shortly after intensive chemotherapy. Case 3 was a male of 60 years old whose PLT was 900×10(9)/L when firstly diagnosed ET. The disease progressed to AML after 5 years, whose WT1 increased from 56 (first visit) to3 696 copies/10 000 ABL copies. Moreover leukemia spread to central nervous system (CNS) during chemotherapy. Before allo-HSCT, cases 1 did not achieve remission; case 2 relapsed after a short time of remission and case 3 transferred to CNS leukemia. All of the 3 cases underwent allo-HSCT successfully, and they all achieved completely remission, whose chromosome and gene mutation recovered negative. At the same time, CNS leukemia of case 3 disappeared. The median WT1 decreased to 50 copies/10 000 ABL copies. There was no severe complication during the median time of 5 months after allo-HSCT. Conclusions: The patients transformed to AML had poor prognosis, allo-HSCT was the only method that can cure the disease now.