Search

Purpose: We studied bone marrow (BM) histologic abnormalities in myelodysplastic syndromes (MDS) classified according to WHO criteria to determine their clinical correlates and prognostic value., Patients and Methods: Three hundred one consecutive patients were retrospectively evaluated for BM fibrosis and CD34 immunoreactivity. Marrow fibrosis was assessed following the European consensus guidelines., Results: Moderate to severe BM fibrosis was detected in 17% of cases and was associated with multilineage dysplasia (P = .001), high transfusion requirement (P < .001), and poor-risk cytogenetics (P = .007). CD34+ cell clusters were found in 23% of patients and were associated with WHO categories with excess of blasts (P < .001) and poor-risk cytogenetics (P = .001). In multivariable analysis, BM fibrosis and presence of CD34+ cell clusters had independent negative impact on overall survival (P < .001 and P = .019, respectively) and leukemia-free survival (P < .001 and P = .004, respectively). A hierarchical clustering analysis identified three subsets of patients with distinct clinical features. One cluster consisted mainly of patients with BM fibrosis, multilineage dysplasia, and high transfusion requirement; these individuals had lower overall survival and leukemia-free survival (P = .001 and P < .001, respectively). Within patients stratified according to International Prognostic Scoring System and WHO classification-based Prognostic Scoring System categories, BM fibrosis involved a shift to a one-step more advanced risk group., Conclusion: BM fibrosis identifies a distinct subgroup of MDS with multilineage dysplasia, high transfusion requirement, and poor prognosis and represents an independent prognostic factor that may be useful in clinical decision making. Furthermore, the presence of CD34+ cell clusters is an independent risk factor for progression to acute leukemia.

Philadelphia-negative chronic myeloproliferative disorders (CMD) include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). Angiogenesis is critical in the pathogenesis of PMF. We studied angiogenesis in 115 patients with CMD (23 PV, 24 ET, 46 PMF, 12 post-PV and 10 post-ET myelofibrosis) by assessment of microvessel density (MVD) in bone marrow (BM). Kruskall-Wallis analysis of variance showed that patients with PMF had significantly higher values of MVD than those with PV (P < 0.001), ET (P < 0.001) and controls (P < 0.001). Mann-Whitney U-test demonstrated that patients with PMF at the prefibrotic stage had significantly higher MVD values than those with ET (P = 0.02). Patients with post-PV myelofibrosis showed significantly higher MVD values than those with PV (P < 0.001), as did patients with post-ET myelofibrosis compared with ET (P < 0.001). In patients with CMD, the multivariate generalized linear regression model showed that the JAK2 (V617F) mutational burden (P = 0.01), serum lactate dehydrogenase level (P = 0.003), and anaemia (P < 0.001) independently correlated with MVD. In summary, this study indicates that assessment of BM angiogenesis, as measured by MVD, may be a useful additional tool in the histopathological definition of CMD.

Introduction: About 15% of people with a myeloproliferative neoplasm (MPN) are identified as MPN, unclassifiable using the 2016 WHO classification. Methods: We tested whether persons with platelet concentration ≥450 × 10E+9/L, bone marrow megakaryocyte morphology typical of prefibrotic/early myelofibrosis (pre-MF), and no minor criteria of pre-MF should be classified as a distinct MPN subtype, clonal megakaryocyte dysplasia with isolated thrombocytosis (CMD-IT). Results: 139 subjects meet these criteria who we compared with primary myelofibrosis (PMF) including 402 with pre-MF and 521 with overt myelofibrosis. CMD-IT subjects were more likely female and younger. They had lower frequencies of JAK2V617F compared with persons with PMF (55% vs. 70%; p < 0.001) and higher frequencies of CALR mutations (37% vs. 17%; p < 0.001). They also had lower frequency of variations associated with JAK2V617F susceptibility, JAK2 46/1 (35% vs. 47%; p = 0.021), and VEGFA rs3025039 (12% vs. 17%; p = 0.030). Subjects with CMD-IT had lower incidences of thrombotic events compared with those with pre-MF (9.7% vs. 26%; p < 0.001) and longer survival (median, not reached vs. 23 years; HR = 0.34 (0.10, 0.30); p < 0.001). Conclusion: Our data indicate CMD-IT is a distinct MPN subtype and should be included in the classification of myeloid neoplasms. [ABSTRACT FROM AUTHOR]

Introduction: In 1991, we reported 18 persons with a clinical-pathologic entity and termed atypical myeloproliferative disorder because they did not meet the contemporary diagnostic criteria for a myeloproliferative neoplasm. We sought to gain further knowledge on this disease entity. Methods: This retrospective cohort study included consecutive subjects registered in the database of the Center for the Study of Myelofibrosis in Pavia, Italy, from 1998 to 2020 (June), and diagnosed with atypical myeloproliferative disorder according to our adjudicated criteria. We studied clinical, histological, cytogenetic, and molecular covariates and risks of thrombosis, disease progression, and death. Data were compared with those of concurrent subjects with prefibrotic myelofibrosis. Results: Fifteen new subjects with atypical myeloproliferative disorder were identified. Seven were male. Median age was 50 years (IQR, 41–54 years). Thirteen were diagnosed with a synchronous symptomatic or incidentally detected thrombotic event. The bone marrow showed megakaryocyte hyperplasia with dysplasia. JAK2V617F was present in 10 subjects and CALR mutation in one. No other somatic mutations were identified in next generation sequencing. After a median follow-up of 101 months (IQR, 40–160 months), no subject had disease progression or blast transformation. Incidence of post-diagnosis or recurrent thrombosis was 3.9 events (95% confidence interval, 3.5–4.0) and 5.0 events (4.6–5.6) per 100 person-years. Features of subjects with atypical myeloproliferative disorder differed markedly from those of 546 subjects with prefibrotic myelofibrosis. Conclusion: Our data indicate that these 15 persons have a distinct myeloproliferative neoplasm. We propose naming this new disorder clonal megakaryocyte dysplasia with normal blood values. [ABSTRACT FROM AUTHOR]