Diagnostic anatomopathologique des néoplasies myéloprolifératives chroniques Ph-

In WHO classifications of myeloproliferative neoplasms, a bone marrow biopsy at diagnosis is mandatory in almost all cases to classify the disease as well as to evaluate the prognosis. The “pre-fibrotic” form, which has been described for several years as distinct from primary myelofibrosis with overt myelofibrosis, is included in the most recent version of these classifications published in 2016. The importance of the biopsy in the diagnosis of polycythemia vera is also growing. Re-evaluation committees bringing together hematopathologists are set up to improve the reproducibility of these histological criteria.