Cytogenetic studies in polycythemia vera

A group of 54 patients with the original diagnosis of polycythemia vera were subjected to cytogenetic examination. Six (17.6%) of the 34 cases examined in the period of the advanced phase of the polycythemia vera had a chromosomal change. Thirteen (65%) of the 20 patients undergoing the cytogenetic examination in the period when the polycythemia vera turned into another myeloproliferative disease showed chromosomal aberration. This suggests a relationship between the number of chromosomal changes and the transformation of the disease. No connection between the cytogenetic changes and myelosuppressive cures could be confirmed in our material. The chromosomal change 20q- considered to be the most frequent kind in the polycythemia vera was not discovered until in patients with the polycythemia vera transformed into a different myeloproliferative disease.     

Myelodysplastic syndrome with trisomy 11 associated with polycythemia vera

A 52-year-old male with myelodysplastic syndrome (MDS) who had a prior history of polycythemia vera is reported. Chromosome analysis revealed that the bone marrow and blood cells at the MDS phase contained trisomy of chromosome 11 as the sole cytogenetic change. Trisomy 11 is rarely found in hematologic neoplasia, and all of the reported cases with trisomy 11 were diagnosed as having nonlymphocytic neoplasia. In this report, a correlation between the chromosome change and leukemia/MDS developed in polycythemia vera is discussed.     

Leukemic transformation of polycythemia vera after treatment with hydroxyurea with abnormalities of chromosome 17

The leukemogenic risk attributed to therapy of polycythemia vera with radiophosphorus and alkylating drugs has led, over the last 20 years, to the increased use of myelosupressive nonmutagenic drugs, especially hydroxyurea. But there exist reports, which showed the development of polycythemia vera into acute leukemia not only in patients treated with alkylating agents and radiophosphorus but also with single hydroxyurea. In this article we present two cases of polycythemia vera, in which the development to acute myeloblastic leukemia occurred after long-term treatment with hydroxyurea. Significant is the fact, that in both presented cases cytogenetic and FISH analysis showed abnormalities of chromosome 17, in the one of case fullfilled criteria for "17p-syndrome". Due to the possibility of leukemogenic potential in the time of hydroxyurea treatment, it is necessary to be careful especially in young patients. The dynamic follow up of cytogenetic analysis is necessary, especially, in those, where long-term hydroxyurea therapy is supposed.     

Familial polycythemia vera with Budd-Chiari syndrome in childhood

Polycythemia vera is a myeloproliferative disorder that, in most cases, occurs sporadically with a median age at presentation of 60 years. Familial cases are very rare and usually manifest in elderly family members. The Budd-Chiari syndrome, characterized by the obstruction and occlusion of the suprahepatic veins, is a rare typical complication in polycythemia vera patients. To date, only two children or adolescents with polycythemia vera and Budd-Chiari syndrome have been described. Here, we report an 11-year-old girl with Budd-Chiari syndrome as the initial symptom of familial polycythemia vera, which was also found in the girl's grandmother. Details of the diagnostic procedures used and the clinical course are reported. The patient underwent orthotopic liver transplantation and is being treated with hydroxyurea. The available literature on familial polycythemia vera and polycythemia vera in childhood with and without Budd-Chiari syndrome is reviewed.     

Isolated cerebellar infarction as a presenting symptom of polycythemia vera.

Although polycythemia vera is one of the reported causes for cerebral infarction, isolated cerebellar infarction, a rare disorder, was never reported in combination with polycythemia vera. This is a report of a 72-year-old woman in whom isolated cerebellar infarction was the presenting manifestation of polycythemia vera. The patient was treated with recurrent phlebotomies until the hematocrit decreased to < 45%. This treatment was followed by marked neurological improvement. A better awareness of the possibility of cerebellar infarction in polycythemia vera may disclose additional cases.     

Karyotype and molecular cytogenetic studies in polycythemia vera

A minority of patients with newly diagnosed polycythemia vera (PV) have an abnormal karyotype in their myeloid cells but no invariant chromosomal aberration has been found. The most frequent visible alteration is a 20q deletion, also characterized in other myeloproliferative diseases (MPD) and myeloid malignancies; among other chromosomal changes, trisomy 9 appears more common in PV than in other MPDs. When a myelofibrosis complicates the course of the disease, cytogenetic anomalies become quite common with a striking frequency of partial duplication 1q; an evolution towards myelodysplasia or acute leukemia is almost always associated with nonspecific chromosomal aberrations. Modern cytogenetic methods have disclosed cryptic anomalies and pointed out the high frequency of 9p alterations affecting a restricted region, thus stimulating an active search for candidate genes or specific mutations.     

Leukemic transformation of polycythemia vera after treatment with hydroxyurea and chromosome 17 abnormalities

The authors present two patients with polycythemia vera where they recorded after several years' treatment with hydroxyurea development of acute myeloblastic leukaemia. In both instances they found, associated with leukaemia, abnormalities of chromosome no.17, in one case meeting criteria of the so-called 17p-syndrome. Progression of polycythemia vera into acute leukaemia is explained by the possible association with the long-term use of the drug and loss of chromosomal material (short arm of chromosome 17), the part where genes important in the process of leukaemogenesis are located. The authors draw attention to contemplated long-term administration of hydroxyurea to young patients with polycythemia vera. As cytogenetic analysis is a suitable method for evidence of progressing polycythemia vera into acute leukaemia, dynamic follow up of chromosomal changes is necessary, in particular in patients where long-term treatment with hydroxyurea is assumed.     

Trends in the incidence of polycythemia vera among olmsted county,Minnesota residents, 1935–1989

To investigate the suggestion that the incidence of polycythemia vera has increased in recent decades, we ascertained secular trends in the incidence of polycythemia vera in Olmsted County, Minnesota, over the 55-year period, 1935–1989. The inpatient and outpatient medical records of all potential cases of polycythemia vera in Olmsted County residents were reviewed and the diagnostic criteria of the Polycythemia Vera Study Group were applied. We found no indication of an increase in the age- and sex-adjusted incidence of polycythemia vera, which averaged 1.9 per 100,000 person-years (95% C.I., 1.4–2.5) over the study period. Incidence rates increased with age, and age-adjusted incidence rates were greater for men (2.8 per 100,000 person-years; 95% C.I., 1.8–3.9) than for women (1.3 per 100,000 person-years; 95% C.I., 0.7–1.9), with the highest incidence rate (23.5 per 100,000 person-years) among men aged 70–79 years. Survival was reduced in this inception cohort of 50 cases, compared to that expected for individuals of like age and sex (P < 0.0001); median survival following diagnosis was 7.2 years. © 1994 Wiley-Liss, Inc.     

Polycythemia vera in identical twins

The occurrence of polycythemia vera in family members has been a rare event, with little or no documentation in the literature to suggest a common genetic defect. We report here on the first case of polycythemia vera documented in identical twins. No chromosomal abnormalities have yet been detected in these patients. The criteria for the diagnosis of polycythemia vera are reviewed, and the possible implications of our findings are discussed.     

A case of Budd-Chiari syndrome secondary to multiple thrombogenic conditions: a case report and review of literature.

This report describes a case of Budd-Chiari syndrome caused by latent polycythemia vera and factor V Leiden mutation. This syndrome usually occurs due to thrombosis of hepatic veins or membranous obstruction of inferior vena cava. The most common reasons for thrombosis are manifest polycythemia vera and the other prothrombotic conditions. Recently, latent polycythemia vera and factor V Leiden mutation have been reported in increasing frequency. In this report, we aimed to emphasize that all prothrombotic conditions must be evaluated while investigating the etiology of Budd-Chiari syndrome, including latent polycythemia vera and factor V Leiden mutation, and appropriate antithrombotic and surgical therapies must be performed without delay.     

Polycythemia vera in childhood: Case report and review of the literature

A patient presented at 5 years of age with polycythemia vera. He subsequently developed splenic infarctions and died at 20 years of age following cerebral hemorrhage and infarctions. Two months before his death, he developed hypertension and had biochemical evidence of primary hyperparathyroidism and possibly pheochromocytoma. Only nine reported childhood cases of polycythemia vera fulfill the criteria of the Polycythemia Vera Study Group. These cases are summarized and the complications discussed. Although none have progressed to myeloid metaplasia or acute leukemia, these patients are at risk of developing thrombo-hemorrhagic complications; available evidence indicates that they should be managed to keep the hematocrit between 40 and 45%.     

Anticoagulant-resistant thrombophilia in a patient with polycythemia vera: a case report

Mechanical valve thrombosis is a rare condition in an adequately anticoagulated patient in the absence of underlying thrombophilia. We report a case of a 76-year-old male with mechanical prosthetic mitral valve thrombosis as the presenting feature of polycythemia vera. The patient was treated with thrombolysis at the time of acute presentation and subsequently maintained on low molecular weight heparin, low-dose aspirin, phlebotomy and hydroxyurea. Hemoglobin, leucocytosis and platelet count were controlled for almost 4 years after which the patient suffered a second, fatal episode in the setting of therapeutic anti-Xa level. This case report highlights the thrombotic risks associated with polycythemia vera. The proposed mechanisms of hypercoagulability in polycythemia vera are reviewed. To the best of our knowledge, mechanical valve thromboses as the presenting feature of polycythemia vera has not been reported previously.     

Megakaryoblastic transformation of polycythemia vera associated with hypercalcemia

Leukemic transformation is not uncommon in polycythemia vera, particularly after treatment with chemotherapeutic agents. The leukemias that supervene are mostly of myeloid type but megakaryoblastic transformation is distinctly uncommon. We report a case of polycythemia vera terminating in megakaryoblastic leukemia with associated hypercalcemia.     

Polycythemia vera--a case report and discussion on pathogenic mechanisms of increased thrombosis

Polycythemia vera is a myeloproliferative disorder characterized by increased red cell mass and frequently complicated by venous and arterial thrombosis. The mechanism underlying the increased incidence of thrombotic events remains illusive. Presented in this report are a case of a 77-year-old man diagnosed with polycythemia vera and a review of the current literature on the mechanisms underlying the increased incidence of thrombotic events in polycythemia vera.     

Pulmonary hypertension in polycythemia vera

Thromboembolic events occur in about 27% of the patients with polycythemia vera and account for 31% of the deaths. These include cerebrovascular accidents, myocardial infarction, peripheral vascular occlusions, pulmonary infarctions, and venous thrombosis. We report two cases with polycythemia vera who presented with pulmonary hypertension in the absence of previous thromboembolic complications of any kind. One patient died suddenly, with evidence of extensive bilateral thrombosis of prelobular pulmonary arteries at autopsy. In the second patient, local thrombosis in the pulmonary vasculature or recurrent silent pulmonary emboli appear to be responsible for the development of pulmonary hypertension. After institution of anticoagulant therapy, he is able to maintain his functional status. The purpose of this report is to alert clinicians to the development of this insidious, but potentially fatal complication in patients with polycythemia vera. © 1994 Wiley-Liss, Inc.     

Genetic studies in the evaluation of myeloproliferative neoplasms

Myeloproliferative neoplasms that include the specific entities of chronic myeloid leukemia, chronic neutrophilic leukemia, polycythemia vera, essential thrombocythemia, and primary myelofibrosis are characterized by the clonal expansion of hematopoietic precursor cells and consequent neoplastic production of mature cells of myeloid, erythroid, and/or megakaryocytic lineage. Genetic studies, encompassing both cytogenetic and molecular testing, play a central and ever increasing role in the assessment of these neoplasms and are the focus of this review.     

Clonal cytogenetic abnormalities in patients with otherwise typical aplastic anemia

Between June 1981 and August 1986, 183 patients with the referring diagnosis of aplastic anemia were evaluated with cytogenetic studies and marrow biopsies. Seven patients (4%) on biopsy were found to have myelodysplasia. Seven of the 176 patients (4%) with marrow biopsies that confirmed the pathologic diagnosis of severe aplastic anemia were found to have clonal cytogenetic abnormalities in unstimulated marrow samples. Among the 169 patients with typical aplastic anemia and no cytogenetic abnormalities, 5 (3%) subsequently developed either myelodysplasia or leukemia. Two of three patients with pathologically confirmed aplastic anemia and clonal cytogenetic abnormalities, who were not transplanted, developed myelodysplasia. These results demonstrate that approximately 4% of patients with aplastic anemia have clonal cytogenetic abnormalities of marrow cells, and that while all patients with aplastic anemia may have some risk of developing leukemia, those with a cytogenetic abnormality have an especially high risk.     

Re-emergence in remission of primary clone in acute myelogenous leukaemias with multiple chromosomal aberrations at diagnosis

We describe the clinical, haematological and cytogenetic features of three patients who had acute myelogenous leukaemia (AML) with complex bone marrow karyotypes when first cytogenetically examined. Induction chemotherapy led to remission from the acute leukaemia. However, neither clinically nor morphologically did this remission mean a return to normal haematopoiesis. The two patients who displayed myelodysplastic features before and when AML was diagnosed, again developed myelodysplasia, and the third patient, who had a long history of polycythaemia vera, returned to this myeloproliferative condition. Nor was cytogenetic normalization achieved; instead, abnormal cell clones were found in which all but one of the karyotypic aberrations present at acute leukaemia diagnosis had disappeared. The solitary anomalies that were detected in these reemerging clones must correspond to the primary cytogenetic aberrations of the patients pre-leukaemic diseases. They were del(5) (q11q33) and del(17) (p11) in the two myelodysplastic cases, and der(18)t(9;18) (p11;p11) in the patient with long-standing polycythaemia vera. The other, secondary, aberrations were probably the leukaemogenic changes, and with the eradication or reduction of the subclones containing them, the leukaemic phenotype disappeared. The three cases add cytogenetic evidence to the growing understanding that the remission obtained in some AMLs is actually a return to a preleukaemic, myeloproliferative or myelodysplastic, syndrome.     

Frequent reduction or absence of detection of the JAK2-mutated clone in JAK2V617F-positive patients within the first years of hydroxyurea therapy

We analyzed the effect of hydroxyurea on the JAK2V617F allelic ratio (%JAK2V617F), measured in purified blood granulocytes, of patients with polycythemia vera and essential thrombocythemia. Thirty-six patients were examined sequentially prior to and after start of hydroxy-urea therapy (8 polycythemia vera, 17 essential thrombocythemia), or while remaining untreated (2 polycythemia vera, 9 essential thrombocythemia). Hydroxyurea therapy (median duration: 15 months) reduced the %JAK2V617F by >30% in 13/25 patients (4 polycythemia vera, 9 essential thrombocythemia). For 3 patients, JAK2V617F remained undetectable for 3-27 months. In addition, a single time point study of two large cohorts of patients, examined either at the time of diagnosis (99 polycythemia vera, 178 essential thrombocythemia) or while receiving hydroxyurea (36 polycythemia vera, 98 essential thrombocythemia; median length of therapy: 32 months), confirmed reduction of %JAK2V617F in the hydroxyurea-treated group (24% vs. 33% JAK2V617F at diagnosis, p<0.01). Prospective studies are needed to determine the prognostic value of reduced JAK2V617F allele burden under cytoreductive therapy.