Primary myelofi brosis

Myelofibrosis (MF) in the context of a myeloproliferative disorder is a clinicopathologically defined entity characterized by anemia, marked splenomegaly, constitutional symptoms, leukoerythroblastosis (i.e., the presence of immature granulocytes and nucleated red blood cells), dacryocytosis (i.e., presence of teardrop-shaped red blood cells), and a bone marrow that displays dysplastic megakaryocyte hyperplasia, granulocyte proliferation, and reticulin and/or collagen fibrosis (1). Disease presentation could be either de novo (primary MF; PMF) or preceded by either polycythemia vera (post-PV MF) or essential thrombocythemia (post-ET MF). PMF is also known by many other names (Table 2.1), including chronic idiopathic myelofibrosis (CIMF), the term used by the World Health Organization (WHO) system for classification of myeloid neoplasms (2). However, the use of the term PMF was recently endorsed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) (3).