Contribution of bone marrow biopsy in the diagnosis and prognosis of polycythemia vera.

As in the other myeloproliferative disorders, it is classical to practice a bone marrow biopsy (MB) in the assessment of Polycythemia Vera (PV). Actually, MB which is a non dangerous and cheap test, will enable to evaluate marrow cellularity, to analyse each myeloid lineage quantitatively and qualitatively in order to determine which one is the most affected and to study reticulin network. In 90% of cases, MB will confirm the clinical and biological diagnosis of PV (megakaryocytic hyperplasia with dysmegakaryopoiesis) and show an increase in reticulin network in more than 25% of cases. However, in 10% of cases, BM will be quite normal. This can be explained by heterogeneity of lesions or a superficial biopsy sampling a few medullar spaces which are often hypocellular. At diagnosis time, myelofibrosis does not seem to be a bad histo-prognosis criterion. In the management of the patient with PV, MB is necessary to detect myelofibrosis and/or AL.