| Abstrakt | | The knowledge of molecular and clinical basis of myeloproliferative disorders has been changing continuously in the recent years. After understanding the molecular basis of CML and introducing specific modulatory drug - imatinib mesilat, other myeloproliferative disorders seem to be on the same path. Recent discovery of specific single point mutation in JAK2 in 97% of patients with PV and in more than 50% of patients with ET and CIM, laid new opportunities for diagnosing, classification, and treatment of CMPD. The introduction of the new WHO classification system for CMPD, which highlighted the value of trephine biopsy in CMPD, by refining the hystological criteria especially for megakaryocyte morphology, is the main shift on the clinical ground. This led to a substantial change in the initial diagnosis especially of ET and CIM. About 70% of cases of ET diagnosed by PVSG criteria (still in a wide use) were changed to CIM. The practical consequence of this change is still unknown.Determination of erythropoetin level has gained definitive place in a differential diagnosis of erythrocytosis and is included in all new classifications. However, the problem of distinguishing CMPD from reactive cases, as well as among themselves still exist, probably until the specific clonal markers are introduced. Currently, the number of false negative diagnoses is significant, e.g. for PV using the PVSG criteria is about 10%. The number of false positive diagnoses is much smaller. According to our experiences there is even a greater problem, i.e. erythrocytosis, thrombocytosis and leukocytosis are often unnoticed or regarded as reactive without sufficient examination and follow-up. As a consequence, diagnosis is delayed and patients present at later stages with fully developed clinical picture or even with major vascular complications. (Abstract truncated at 2000 characters)
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