Abstract
Primary myelofibrosis (PMF) is a disease from the group of Ph–negative myeloproliferative tumors, which is characterized by bone marrow fibrosis, splenomegaly and extramedullary hematopoiesis. The mean life in PMF ranges from 7.6 to 10 years and varies widely depending on the appearance of additional mutations and a higher degree of malignancy. Most patients have an indolent flow, and in some patients with PMF, the disease progresses rapidly with the development of acute myeloblastic leukemia. The international stratification system DIPSS-plus allows predicting the occurrence time of the PMF blast transformation phase. The article presents a case of early PMF transformation into acute myeloblastic leukemia in a patient with a heterozygous mutation in the JAK2 gene and an intermediate risk-2 established according to the International Prognostic Scoring DIPSS-plus. The patient received standard cytoreductive therapy.