Current diagnosis of PMF is based on the 2008 World Health Organization (WHO) criteria, which enlist histopathologic, morphologic, clinical, and molecular-cytogenetic variables. The diagnosis of post-PV or post-ET MF is according to IWG-MRT criteria.

Table 1 Diagnostic Criteria of Myelofibrosis

In all 3 MF variants, typical laboratory features include anemia, peripheral blood leukoerythroblastosis, dacryocytosis, leukocytosis/thrombocytosis, increased lactate dehydrogenase (LDH), excess circulating blasts or CD34+ cells, and bone marrow fibrosis, osteosclerosis, and angiogenesis.

Occasionally, overt bone marrow fibrosis might be absent (ie, prefibrotic PMF) and, in the presence of thrombocytosis, a spurious diagnosis of ET is made. The possibility of prefibrotic PMF, as opposed to ET, should be considered in the presence of persistently increased serum LDH, anemia, leukoerythroblastosis, anemia, leukoerythroblastosis, increased circulating CD34+ cell count, and marked splenomegaly. It is underscored that the distinction between ET and prefibrotic PMF is clinically relevant because both OS and leukemia-free survival are significantly inferior in the latter.

The differential diagnosis of PMF should also include bone marrow fibrosis associated with noneoplastic or other neoplastic conditions, including metastatic cancer, lymphoid neoplasm, or another myeloid malignancy, especially CML, MDS, chronic myelomonocytic leukemia (CMML), or AML. The presence of JAK2 or MPL mutation reliably excludes reative bone marrow fibrosis or a nonmyeloid malignancy.