Essential thrombocythemia: a review of diagnostic and pathologic features

Digital gangrene: can be the first manifestation of essential thrombocythemia? a case report

Introduction and importance

Essential thrombocythemia (ET) is a rare chronic myeloproliferative hematologic disorder, leading to an elevated platelet count. Two-thirds of patients are asymptomatic during their lifetime, while others may experience symptoms like redness, congestion, and erythromelalgia after long symptom-free intervals.

Case presentation

The authors present a rare instance of a 55-year-old female who, despite receiving aspirin and losartan treatment, eventually developed digital gangrene. In further work-ups, she had an elevated platelet count and a positive JAK 2 mutation. Her platelet count was reduced throughout treatment with aspirin, hydroxyurea, and heparin, which was followed by the necrotic tip of her index finger being surgically debrided.

Clinical discussion

Significant symptoms, such as severe acrocyanosis and even peripheral gangrene, can be treated with a single dose of aspirin. Daily aspirin consumption withstanding, this case developed the severe form of ET. In addition, while thrombocytosis predisposes patients to thrombotic complications in theory, there is little evidence to support a correlation between absolute platelet count and thrombosis.

Conclusion

The initial symptom of ET could be such severe and uncommon that may develop arterial acral thrombosis despite previous daily low-dose aspirin consumption.

Essential thrombocythemia: a hemostatic view of thrombogenic risk factors and prognosis

Essential thrombocythemia (ET) is a classical myeloproliferative neoplasm that is susceptible to hypercoagulable state due to impaired hemostatic system, so that thrombotic complications are the leading cause of mortality in ET patients. The content used in this article has been obtained by the PubMed database and Google Scholar search engine from English-language articles (2000-2019) using the following keywords: "Essential thrombocythemia," "Thrombosis," "Risk factors" and "Hemostasis. In this neoplasm, the count and activity of cells such as platelets, leukocytes, endothelial cells, as well as erythrocytes are increased, which can increase the risk of thrombosis through rising intercellular interactions, expression of surface markers, and stimulation of platelet aggregation. In addition to these factors, genetic polymorphisms in hematopoietic stem cells (HSCs), including mutations in JAK2, CALR, MPL, or genetic abnormalities in other genes associated with the hemostatic system may be associated with increased risk of thrombotic events. Moreover, disruption of coagulant factors can pave the way for thrombogeneration. Therefore, the identification of markers related to cell activation, genetic abnormalities, or alternation in the coagulant system can be used together as diagnostic and prognostic markers for the occurrence of thrombosis among ET patients. Thus, because thrombotic complications are the main factors of mortality in ET patients, a hemostatic viewpoint and risk assessment of cellular, genetic, and coagulation factors can have prognostic value and contribute to the choice of effective treatment and prevention of thrombosis.

Rare presentation of iron deficiency anaemia with cerebral venous sinus thrombosis in a middle-aged woman

This is a case of a female patient presented with a mild headache associated with recurrent episodes of nausea and vomiting, confusion and right-sided hemiparesis, diagnosed of haemorrhagic venous infarction from the thrombosis of left transverse and sigmoid sinus and probably the left vein of Labbe. She had severe microcytic hypochromic anaemia due to iron deficiency, without any other risk factors for cerebral venous thrombosis such as trauma history, infections, coagulation disorders or autoimmune diseases. She had a good prognosis after iron supplementation and anticoagulation therapy.

A cross-sectional retrospective study to analyze the underlying causes and clinical characteristics of children with reactive thrombocytosis at a Korean tertiary medical center

Background

Reactive thrombocytosis (RT) is a common condition among children, although no studies have examined the etiology or clinical characteristics of RT among Korean children.

Methods

This retrospective study evaluated children with RT at a single Korean tertiary center during a 10-year period.

Results

RT accounted for 13.5% of children who were admitted to the pediatric ward (4,113/30,355): mild RT, 82.7%; moderate RT, 14.1%; severe RT, 1.1%; and extreme RT, 2.1%. There was a negative correlation between platelet count and Hb level (P=0.008). There were positive correlations between platelet count and WBC (P=0.001), erythrocyte sedimentation rate (ESR) (P=0.007), and admission duration (P=0.006). The most common cause of RT was infection and the second most common was Kawasaki disease (KD). The highest proportion of lower respiratory tract infection was observed in extreme RT (P<0.001). The proportion of KD was highest in extreme RT (P<0.001) and in children aged 1–7.9 years (P<0.001). The proportion of refractory KD was highest in extreme RT (P=0.005). In cases of KD, there was a positive correlation between platelet count and fever duration (P=0.006). Non-KD autoimmune inflammation was only observed in mild/moderate RT, and its proportion was highest in children aged 8–18 years (P<0.001).

Conclusion

In children, more severe RT was associated with lower Hb, increased WBC, ESR, and prolonged admission. With respiratory infection or KD, extreme RT was associated with more severe disease course.

miR-203 and miR-221 regulate SOCS1 and SOCS3 in essential thrombocythemia

The biological basis of essential thrombocythemia (ET) patients lacking known mutations is still unknown. MicroRNAs (miRNA) regulate hematopoietic differentiation and are deregulated in several hematopoietic malignancies. However, miRNA expression in ET patients has been poorly explored. We performed miRNA profiling in platelets from 19 ET patients and 10 healthy controls. Hierarchical cluster analysis showed two well-separated clusters between patients and controls, indicating that ET platelets had a characteristic 70-miRNA signature (P<0.0001), 68 of which were downregulated. According to the mutational status, three differentially expressed miRNAs, miR-15a (P=0.045), miR-150 (P=0.001) and miR-519a (P=0.036), were identified. A 40-miRNA signature was identified characterizing JAK2V617F-positive ET patients. Eight genes, whose interaction with the miRNAs could activate the JAK/STAT pathway were identified. An inverse correlation was observed between miRNAs expression and their target genes for SOCS1 and miR-221, SOCS3 and miR-221, SOCS3 and miR-203, and PTPN11 and miR-23a. All three miRNAs were upregulated in JAK2V617F-negative ET patients. SOCS1 and SOCS3 were validated as targets of miR-221 and miR-203, respectively. In summary, our study shows that platelets from JAK2V617F-negative ET patients harbor a specific miRNA signature that can participate in the modulation of the JAK/STAT pathway through regulation of key genes as SOCS1 and SOCS3.

Producing megakaryocytes from a human peripheral blood source

BACKGROUND

Cultured megakaryocytes could prove useful in the study of human diseases, but it is difficult to produce sufficient numbers for study. We describe and evaluate the use of an expansion process to develop mature megakaryocytes from peripheral blood-derived human hematopoietic stem and progenitor cells (HSPCs).

STUDY DESIGN AND METHODS

HSPCs (CD34+) were isolated from peripheral blood by positive selection and expanded using an optimal CD34+ expansion supplement. We evaluated megakaryocyte growth, maturation, and morphology in response to thrombopoietin (TPO) stimulation using flow cytometry and electron microscopy. TPO demonstrated a dose-dependent stimulatory effect on both megakaryocyte number and maturation.

RESULTS

From 90 to 120 mL of unmanipulated peripheral blood, we isolated a mean of 1.5 × 10(5) HSPCs (1.5 × 10(3) cells/mL of whole blood). HSPCs expanded nine-fold after a 4-day culture using an expansion supplement. Expanded cells were cultured for an additional 8 days with TPO (20 ng/mL), which resulted in a 2.9-fold increase in megakaryocytic cells where 83% of live cells expressed CD41a+, a marker of megakaryocyte commitment, and 50% expressed CD42b+, a marker for megakaryocyte maturation. The expanded HSPCs responded to TPO stimulation to yield more than 1.0 × 10(6) megakaryocytes. This cell number was sufficient for morphologic studies that demonstrated these expanded HSPCs produced mature polyploid megakaryocytes capable of forming proplatelet extensions.

CONCLUSIONS

Peripheral blood HSPCs can be expanded and differentiated into functional, mature megakaryocytes, a finding that supports the use of this process to study inherent platelet (PLT) production disorders as well as study factors that impair normal PLT production.

Retinal Vessel Caliber, Choroidal Thickness and Ocular Pulse Amplitude Measurements in Essential Thrombocythemia

PURPOSE

The choroid and retina receive most of the blood that enter to the eye, and this uptake may be affected by essential thrombocythemia (ET) in which thrombosis and hemorrhage is common. This study compares choroidal thickness, retinal vascular caliber, and ocular pulse amplitude (OPA) measurements between patients with ET and healthy adults.

MATERIALS AND METHODS

Thirty-seven patients with ET and 37 age-sex-matched healthy adults were recruited in this cross-sectional and comparative study. Spectral-domain optical coherence tomography was used to measure the subfoveal choroidal thickness (SFCT) and retinal vascular caliber measurements. The Pascal dynamic contour tonometer was used for OPA and intraocular pressure (IOP) measurements. The independent samples t-test was used for comparison of measurements between the groups. Pearson's correlation coefficient analysis was used to detect correlations between the variables. A P < 0.05 was statistically significant.

RESULTS

SFCT, OPA, and IOP measurements were not statistically significant differences between the study group and the control group (P > 0.05, all comparisons). Blood platelet counts were not associated with choroidal thickness, OPA, and IOP (P > 0.05). Retinal arteriolar and venular calibers were statistically, significantly thicker in healthy controls when compared to the study group (P < 0.05).

CONCLUSIONS

Our results indicate that choroidal thickness and pulsatile blood flow are not significantly affected in ET and under high blood platelet counts. Retinal arteriolar and venular calibers are thinner in ET when compared to age-sex matched healthy controls.

Acute ST-segment elevation myocardial infarction as the first manifestation of essential thrombocytosis successfully treated with thrombectomy alone

A patient with no conventional cardiovascular risk factors presented with inferior ST-elevation myocardial infarction which was finally diagnosed as a case of essential thrombocytosis. This case demonstrated that thrombectomy alone was sufficient for the treatment of his coronary occlusion. Furthermore, this case report highlights the importance of evaluating rare causes of myocardial infarction other than atherosclerosis and that internists and cardiologists should be aware of essential thrombocytosis as a known cause of myocardial infarction, particularly in patients with no underlying cardiovascular risk factors.

The contribution of cyclooxygenase-1 and -2 to persistent thromboxane biosynthesis in aspirin-treated essential thrombocythemia: implications for antiplatelet therapy

We tested whether cyclooxygenase 2 (COX-2) expression and unacetylated COX-1 in newly formed platelets might contribute to persistent thromboxane (TX) biosynthesis in aspirin-treated essential thrombocythemia (ET). Forty-one patients on chronic aspirin (100 mg/day) and 24 healthy subjects were studied. Platelet COX-2 expression was significantly increased in patients and correlated with thiazole orange–positive platelets (r = 0.71, P < .001). The rate of TXA2 biosynthesis in vivo, as reflected by urinary 11-dehydro-TXB2 (TXM) excretion, and the maximal biosynthetic capacity of platelets, as reflected by serum TXB2, were higher in patients compared with aspirin-treated healthy volunteers. Serum TXB2 was significantly reduced by the selective COX-2 inhibitor NS-398 added in vitro. Patients were randomized to adding the selective COX-2 inhibitor, etoricoxib, or continuing aspirin for 7 days. Etoricoxib significantly reduced by approximately 25% TXM excretion and serum TXB2. Fourteen of the 41 patients were studied again 21 (± 7) months after the first visit. Serum TXB2 was consistently reduced by approximately 30% by adding NS398 in vitro, while it was completely suppressed with 50μM aspirin. Accelerated platelet regeneration in most aspirin-treated ET patients may explain aspirin-persistent TXA2 biosynthesis through enhanced COX-2 activity and faster renewal of unacetylated COX-1. These findings may help in reassessing the optimal antiplatelet strategy in ET.

Autoimmunity and the risk of myeloproliferative neoplasms

The causes of myeloproliferative neoplasm (MPN) are unknown. We conducted a large population-based study including 11,039 myeloproliferative neoplasm patients and 43,550 matched controls with the aim of assessing the associations between a personal history of a broad span of autoimmune diseases and subsequent risk of myeloproliferative neoplasm. We found a prior history of any autoimmune disease to be associated with a significantly increased risk of myeloproliferative neoplasms (odds ratio (OR)=1.2; 95% confidence interval (CI) 1.0-1.3; P=0.021). Specifically, we found an increased risk of MPNs associated with a prior immune thrombocytopenic purpura (2.9; 1.7-7.2), Crohn's disease (1.8; 1.1-3.0), polymyalgia rheumatica (1.7; 1.2-2.5), giant cell arteritis (5.9; 2.4-14.4), Reiter's syndrome (15.9; 1.8-142) and aplastic anemia (7.8; 3.7-16.7). The risk of myeloproliferative neoplasms associated with prior autoimmune diseases is modest but statistically significant. Future studies are needed to unravel the effects of these autoimmune diseases themselves, their treatment, or common genetic susceptibility.

Germline and somatic JAK2 mutations and susceptibility to chronic myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are a group of closely related stem-cell-derived clonal proliferative diseases. Most cases are sporadic but first-degree relatives of MPN patients have a five- to seven-fold increased risk for developing an MPN. The tumors of most patients carry a mutation in the Janus kinase 2 gene (JAK2(V617F)). Recently, three groups have described a strong association of JAK2 germline polymorphisms with MPN in patients positive for JAK2(V617F). The somatic mutation occurs primarily on one particular germline JAK2 haplotype, which may account for as much as 50% of the risk to first-degree relatives. This finding provides new directions for unraveling the pathogenesis of MPN.

Essential thrombocythemia: a case of acute ST-segment elevation myocardial infarction in a young female

Essential thrombocythemia (ET) is a clonal disorder of the myeloid stem cell that causes abnormal proliferation of the megakaryocytes. The main feature of the disease is arterial and venous thrombosis caused by platelet dysfunction. Coronary artery involvement leading to acute coronary syndromes is a rare complication of the ET. We report a coronary angioplasty and stenting in a 30-year-old female patient with acute ST-segment elevation myocardial infarction (MI) as the first clinical sign of essential thrombocythemia. Facilitated percutaneous coronary intervention with GPIIb/IIIa and/or thrombolytic therapy may be considered as the first treatment modality for this patient group.

The implication of identifying JAK2 ( V617F ) in myeloproliferative neoplasms and myelodysplastic syndromes with bone marrow fibrosis

The myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS) occasionally demonstrate overlapping morphological features including hypercellularity, mild/nonspecific dysplastic changes and variable bone marrow fibrosis. Thus, when the associated bone marrow fibrosis results in a suboptimal specimen for morphological evaluation, the descriptive diagnosis "fibrotic marrow with features indeterminate for MDS versus MPN" is often applied. The JAK2 ( V617F ) mutation was recently shown to be frequently identified in MPN, but it is rarely present in other myeloid disorders. However, the diagnostic utility of JAK2 ( V617F ) screening in hypercellular bone marrow specimens with fibrosis has not been previously investigated. Using a real-time polymerase chain reaction melting-curve assay capable of detecting JAK2 ( V617F ) in archived fixed materials, we retrospectively studied JAK2 ( V617F ) in 45 cases with fibrotic hypercellular bone marrow at initial presentation, including 19 cases initially described as "with features indeterminate for MDS versus MPN". These 19 cases were reclassified into more specific categories of MDS (n = 14) or MPN (n = 5) based on the availability of subsequent clinical data and/or bone marrow examinations. The JAK2 ( V617F ) allele was identified in 17 out of 18 BCR/ABL gene-negative MPN cases with marrow fibrosis, whereas only wild-type alleles were identified in the remaining non-MPN cases. Importantly, JAK2 ( V617F ) alleles were seen in all five cases of "with features indeterminate for MDS versus MPN" at initial presentation that were later determined to be MPN, but they were absent in the 14 cases later determined to be MDS. Our results suggest that JAK2 ( V617F ) allele evaluation can be a useful ancillary test for discriminating MDS from MPN in specimens with bone marrow fibrosis.

Severe thrombocytosis and anemia associated with celiac disease in a young female patient: a case report

INTRODUCTION

Platelet counts exceeding 1.000 x 103/microl are usually considered secondary to another cause, particularly to chronic myeloproliferative disease (CMPD). Reactive thrombocytosis due to iron deficiency rarely exceeds platelet counts of 700 x 103/microl.

CASE PRESENTATION

Here we report the case of a young woman presenting with clinical signs of severe anemia. Laboratory findings confirmed an iron-deficiency anemia associated with severe thrombocytosis of 1703 x 103/microl. Macroscopic gastrointestinal and genitourinary tract bleeding was excluded. The excessive elevation of platelets, slightly elevated lactate dehydrogenase and slightly elevated leukocytes along with the absence of other inflammation parameters raised the suspicion of an underlying hematological disease. However, bone marrow evaluation could not prove the suspected diagnosis of a CMPD, especially essential thrombocythemia (ET). In the further clinical course the platelet count returned to normal after raising the hemoglobin to a level close to normal range with erythrocyte transfusion, and normalization of serum iron and decline of erythropoietin. Finally, following small bowel biopsy, despite the absence of typical clinical signs, celiac disease was diagnosed. After discharge from hospital the patient was commenced on a gluten-free diet and her hemoglobin almost completely normalized in the further follow-up period.

CONCLUSION

This case illustrates the rare constellation of an extreme thrombocytosis most likely secondary to iron deficiency due to celiac disease. This represents, to the best of the authors' knowledge, the highest reported platelet count coincident with iron deficiency. A potential mechanism for the association of iron-deficiency anemia and thrombocytosis is discussed. Even in the presence of 'atypically' high platelets one should consider the possibility of reactive thrombocytosis. Extreme thrombocytosis could emerge in the case of iron deficiency secondary to celiac disease.

Pulmonary hypertension in patients with essential thrombocythemia and reactive thrombocytosis

Increased incidence of pulmonary hypertension (PH) has been reported in patients with chronic myeloproliferative disorders. The exact incidence of PH in essential thrombocythemia (ET) is unknown. Most of the reported literature consists of case reports or small studies. We designed this study to asses the incidence of PH in patients with ET and reactive thrombocytosis. Previously or newly diagnosed 46 patients with ET, and 40 patients with reactive thrombocytosis secondary to iron deficiency anemia were found to be eligible for this study. Diagnosis of PH was established via transthoracic echocardiography. PH was found in 22 (47.8%) out of 46 patients with ET. Seven patients with PH were newly diagnosed ET, 5 patients with PH were in low, and the other patients with PH were in intermediate or high risk category. We found statistically significant difference in terms of platelet counts between ET patients with PH and without PH (p = 0.027). None of the patients with reactive thrombocytosis had PH. In conclusion, PH appears to be common in patients with ET. Therefore, all patients with ET should be evaluated for PH. Larger and prospective studies are required to clarify the long-term impact of PH on the survival of these patients. Future studies are also needed to determine whether cytoreductive treatment and aspirin prevent the development of PH, and to determine the effects of cytoreductive treatments and aspirin on the prognosis of PH. The effect of PH on ET prognosis should also be determined in low risk ET patients.

Digital ischemia due to essential thrombocythemia: a case report

This report describes the case of a 34-year-old patient with essential thrombocythemia who presented with Raynaud's syndrome, was refractory to medical treatment, and developed progressive digital gangrene.