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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]

We measured plasma levels of high-sensitivity C-reactive protein (hs-CRP) in 526 subjects with primary myelofibrosis (PMF). Thirty-eight percent had an elevated hs-CRP level (≥ 0.3 mg/dL). Elevated hs-CRP levels were associated with a progressive disease phenotype, including anemia, high white blood cell count, low platelet count, increased splenomegaly, increased risk of blast transformation, and worse survival. Age ≥ 52 years, but no other demographic characteristics, was associated with an elevated hs-CRP level in multivariable logistic regression (odds ratio [OR], 4.29; 95% CI, 2.73-6.77; P < 0.001). Subjects with JAK2 V617F mutation and an allele burden ≥ 50% had an age-independent higher incidence of elevated hs-CRP level (OR = 1.97; 95% CI,1.21–3.22; P = 0.006) compared with a combined cohort of subjects with JAK2 V617F <50% allele burden, CALR, MPL mutations, or no detectable driver mutations. Neither ASXL1 or EZH2 sub-clonal mutations, nor JAK2 46/1 haplotype or the A3669G polymorphism of glucocorticoid receptor were significantly associated with increased hs-CRP levels. Subjects with age ≥ 52 years and JAK2 V617F with ≥ 50% allele burden had a phenotype of progressive disease. Our data indicate that older age and high JAK2 V617 allele burden are major determinants of inflammation in PMF, and are associated with disease progression. [ABSTRACT FROM AUTHOR]

Increased microvessel density contributes to abnormal BM and spleen microenvironment in myelofibrosis (MF). Taking advantage of the JAK2V617F mutation as a marker of malignancy, in the present study, we investigated whether splenic endothelial cells (ECs) obtained from capillaries by laser microdissection or from fresh spleen tissue by cell culture or cell sorting harbored such mutation in patients bearing the mutation in their granulocytes and undergoing splenectomy for therapeutical reasons. To extend the analysis to the ECs of large vessels, endothelial tissue from the splenic vein was also studied. We found JAK2V617F+ ECs in 12 of 18 patients also bearing the mutation in their granulocytes. In 3 patients, the mutation was found in at least 2 different EC samples obtained by laser microdissection, cell culture, or cell sorting. The mutation was detected in the splenic vein ECs of 1 of 6 patients investigated. In conclusion, we provide evidence that some ECs from the spleen and splenic veins of patients with MF bear the JAK2V617F mutation. We suggest that splenic ECs are involved in the process of malignant transformation in MF. [ABSTRACT FROM AUTHOR]

Background: MYH9-related disease (MYH9-RD) is a rare autosomal dominant genetic syndrome characterized by congenital thrombocytopenia associated with the risk of developing progressive nephropathy, sensorineural deafness, and presenile cataract. During the collection of a large case-series of patients with MYH9-RD we noticed several cases with unexplained elevation of liver enzymes. Our aim was to evaluate if the alteration of liver tests is a feature of the MYH9-RD and to define its clinical significance. Methods and Findings: Data concerning liver tests, prospectively recorded in the Italian Registry for MYH9-RD, were collected and compared with those of three control populations: patients with autoimmune thrombocytopenia, patients with inherited thrombocytopenias other than MYH9-RD, and the participants to a large epidemiologic survey in an Italian geographic isolate. Thirty-eight of 75 evaluable MYH9-RD patients (50.7%) showed an elevation of ALT and/or AST, and 17 of 63 (27.0%) an increase of GGT. The increases ranged from 1.9±0.7 to 2.7±1.6 fold the upper normal limit. The prevalence of liver test alterations was significantly higher in MYH9-RD patients than in each of the control populations, with odds ratios ranging from 8.2 (95% CIs 2.2-44.8) to 24.7 (14.8-40.8). Clinical follow-up and more detailed liver studies of a subset of patients, including ultrasound liver scan, liver elastography and liver biopsy in one case, did not show any significant structural damage or evolution towards liver insufficiency. Conclusions: Elevation of liver enzymes is a frequent and previously unrecognized feature of the MYH9-RD syndrome; however, this defect does not appear to have poor prognostic value. [ABSTRACT FROM AUTHOR]

Purpose: In the WHO diagnostic classification, prefibrotic myelofibrosis (pre-MF) is included in the category of primary myelofibrosis (PMF). However, strong evidence for this position is lacking. Patients and Methods: We investigated whether pre-MF may be aligned along a clinical and biological continuum in 683 consecutive patients who received a WHO diagnosis of PMF. Results: As compared with PMF-fibrotic type, pre-MF (132 cases) showed female dominance, younger age, higher hemoglobin, higher platelet count, lower white blood cell count, smaller spleen index and higher incidence of splanchnic vein thrombosis. Female to male ratio and hemoglobin steadily decreased, while age increased from pre-MF to PMF- fibrotic type with early and to advanced bone marrow (BM) fibrosis. Likely, circulating CD34+ cells, LDH levels, and frequency of chromosomal abnormalities increased, while CXCR4 expression on CD34+ cells and serum cholesterol decreased along the continuum of BM fibrosis. Median survival of the entire cohort of PMF cases was 21 years. Ninety-eight, eighty-one and fiftysix percent of patients with pre-MF, PMF-fibrotic type with early and with advanced BM fibrosis, respectively, were alive at 10 years from diagnosis. Conclusion: Pre-MF is a presentation mode of PMF with a very indolent phenotype. The major consequences of this contention is a new clinical vision of PMF, and the need to improve prognosis prediction of the disease. [ABSTRACT FROM AUTHOR]

Increased mobilization of circulating endothelial progenitor cells may represent a new biological hallmark of myeloproliferative neoplasms. We measured circulating endothelial colony forming cells (ECFCs) in 106 patients with primary myelofibrosis, fibrotic stage, 49 with prefibrotic myelofibrosis, 59 with essential thrombocythemia or polycythemia vera, and 43 normal controls. Levels of ECFC frequency for patient's characteristics were estimated by using logistic regression in univariate and multivariate setting. The sensitivity, specificity, likelihood ratios, and positive predictive value of increased ECFC frequency were calculated for the significantly associated characteristics. Increased frequency of ECFCs resulted independently associated with history of splanchnic vein thrombosis (adjusted odds ratio = 6.61, 95% CI = 2.54-17.16), and a summary measure of non-active disease, i.e. hemoglobin of 13.8 g/dL or lower, white blood cells count of 7.8x109/L or lower, and platelet count of 4006109/L or lower (adjusted odds ratio = 4.43, 95% CI = 1.45-13.49) Thirteen patients with splanchnic vein thrombosis non associated with myeloproliferative neoplasms were recruited as controls. We excluded a causal role of splanchnic vein thrombosis in ECFCs increase, since no control had elevated ECFCs. We concluded that increased frequency of ECFCs represents the biological hallmark of a non-active myeloproliferative neoplasm with high risk of splanchnic vein thrombosis. The recognition of this disease category copes with the phenotypic mimicry of myeloproliferative neoplasms. Due to inherent performance limitations of ECFCs assay, there is an urgent need to arrive to an acceptable standardization of ECFC assessment. [ABSTRACT FROM AUTHOR]

Reported herein is an unusual vascular tumor primary arising in the liver and exhibiting unique histopathological features. A 47-year-old woman underwent left hepatectomy because of a large hepatic mass. On histology the tumor had a composite pattern, consisting of angiomatous, retiform and solid areas, formed by oval to cuboidal to spindle cells, that expressed only endothelial markers (CD31 and factor VIII-related antigen). These findings led to the diagnosis of a low-grade vascular neoplasm with morphological features consistent with so-called polymorphous hemangioendothelioma. The tumor was completely resected. At 24 month follow up the patient was alive, without evidence of disease. Polymorphous hemangioendothelioma is a rare vascular neoplasm, with borderline malignant potential, which usually occurs in lymph nodes and, rarely, at extranodal sites. Its classification as an entity has been questioned recently. The unusual morphological features of the present case, which do not fit neatly with any other recognized hemangioendothelioma subtype, indicate that the family of vascular tumors is broader than currently accepted. In addition the present case widens the spectrum of primary vascular tumors arising in the liver. [ABSTRACT FROM AUTHOR]

Deposition of amyloid in the buttock is a rare complication of dialysis related amyloidosis (DRA), but this localization is even rarer in other types of amyloidoses. We report here the clinical, radiological, and biochemical features of a patient who incurred into this complication after 27 years of hemodialysis. Imaging of the amyloid deposition by magnetic resonance imaging (MRI) documents the amyloid infiltration in the muscles of the buttock region and highlights a peculiar feature of amyloid fibrils deposition in the subcutaneous fat. The amyloid deposition is confirmed by biochemical and microscopic analysis of fibrils extracted from a biopsy specimen. Review of literature and the features of this case lead to speculation that the peculiar involvement of the buttock region including muscles and subcutaneous fat in DRA might derive from the propagation of amyloid initially deposited in the hip joint. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Novel N-glycosylation sites are introduced by somatic mutation into the V genes of the majority of follicular lymphomas. Sites are positively selected and rare in normal memory B cells, indicating a potential role in tumour survival in the germinal centre (GC). The incidence of c. 40% in diffuse large B-cell lymphomas (DLBCL) parallels the known heterogenity of the disease. Immunodeficiency-related non-Hodgkin's lymphomas (NHL) include post-transplant lymphoproliferative disorders (PTLD) and acquired immunodeficiency syndrome-related NHL (AIDS-NHL). Most PTLD derive from B cells that carry mutated VH genes and that have completed the GC reaction. All AIDS-NHL carry mutated VH genes and variable features of GC or post-GC cells. To determine if N-glycosylation is a feature of immunodeficiency-related lymphomas, we analysed the VH genes of 19 PTLD and 36 AIDS-NHL. Novel sites were rare in PTLD (4/19), similar to memory B cells ( P = 0·15). AIDS-NHL, including DLBCL and Burkitt's lymphomas (BL), showed heterogeneity with 16 of 36 (44%) having novel sites. The findings indicate no selection of N-glycosylation sites in PTLD, consistent with post-GC features. The variable incidence of N-glycosylation sites in AIDS-NHL mirrors that in DLBCL and sporadic BL of immunocompetent hosts, supporting the known heterogeneity of these disorders, and possibly pointing to distinct routes of tumour development. [ABSTRACT FROM AUTHOR]

Purpose: May-Hegglin anomaly is a rare hereditary condition characterized by the triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes. Clinical features and the pathogenesis of bleeding in this disease are poorly defined.Patients and Methods: From 1988 to 1996 we studied 15 new May-Hegglin anomaly patients from 7 unrelated Italian families. In addition to clinical examination and routine laboratory testing, we measured bleeding time, platelet aggregation and release reaction, and platelet staining for tubulin, and performed ultrastructural study of polymorphonuclear leukocytes.Results: Although the mean age of our patients was 33 years, May-Hegglin anomaly had not been previously recognized in any of them. Bleeding diatheses ranged from severe to absent, and platelet count from 26 to 178 x 10(9)/L. No correlation was found between bleeding tendency and platelet count. Previous therapy with corticosteroids, high-dose immunoglobulins, and splenectomy had no effect on platelet count or bleeding diathesis. Desmopressin infusion greatly shortened the bleeding time in the most severely affected patient. The in vitro function of platelets was normal except for the absence of shape change in all subjects and defective response to epinephrine in 8 of 15 patients. Platelet tubulin was distributed unevenly instead of being organized in a circumferential band at the cell periphery.Conclusion: The diagnosis of May-Hegglin is easily missed, and its frequency is probably underestimated. A qualitative defect of platelets may be responsible for mild bleeding diathesis even in the absence of thrombocytopenia, while severe bleeding results from both qualitative and quantitative platelet defects. May-Hegglin anomaly should be suspected whenever a patient has a low platelet count or a bleeding diathesis of unknown origin. [ABSTRACT FROM AUTHOR]