Prognostic impact of blast cell counts in dysplastic bone marrow disorders (MDS and CMML I) with concomitant fibrosis

In a retrospective study, 43 patients with dysplastic neoplasms of the bone marrow (myelodysplastic syndromes and myelodysplastic/myeloproliferative-overlap neoplasms) associated with marked (grades 2-3) fibrosis were examined. Histopathologic and morphologic findings as well as cytogenetic and molecular results were correlated with clinical endpoints. Multilineage dysplasia (34 of 43 patients, 79 %) and hypercellular bone marrow (64 %) were found in most patients. In ten of 35 patients, poor risk karyotypes according to the International Prognostic Scoring System (IPSS) were recorded. The JAK2 V617F mutation was detected in four of 30 patients (13 %), and the KIT D816V mutation was found in two of 30 patients (6 %). Patients were mainly treated with palliative drugs and best supportive care. After an observation time of 1-41 (median 21) months, ten of 43 patients (23 %) had developed a secondary acute leukemia. The median survival of all 43 patients was 21.4 months (range 1.8-88.2 months). Of all prognostic parameters examined, the blast cell count at diagnosis was found to be a most reliable and most predictive marker concerning survival and leukemia progression. This confirms previous studies in dysplastic bone marrow neoplasms without fibrosis.