Pulmonary extra-medullary hematopoiesis and pulmonary hypertension from underlying polycythemia vera: a case series

Hematopoietic stem cells and extramedullary hematopoiesis in the lungs

Hematopoietic stem cells are key players in hematopoiesis as the body maintains a physiologic steady state, and the signaling pathways and control mechanisms of these dynamic cells are implicated in processes from inflammation to cancer. Although the bone marrow is commonly regarded as the site of hematopoiesis and hematopoietic stem cell residence, these cells also circulate in the blood and reside in extramedullary tissues, including the lungs. Flow cytometry is an invaluable tool in evaluating hematopoietic stem cells, revealing their phenotypes and relative abundances in both healthy and diseased states. This review outlines current protocols and cell markers used in flow cytometric analysis of hematopoietic stem and progenitor cell populations. Specific niches within the bone marrow are discussed, as are metabolic processes that contribute to stem cell self-renewal and differentiation, as well as the role of hematopoietic stem cells outside of the bone marrow at physiologic steady state. Finally, pulmonary extramedullary hematopoiesis and its associated disease states are outlined. Hematopoiesis in the lungs is a new and emerging concept, and discovering ways in which the study of lung-resident hematopoietic stem cells can be translated from murine models to patients will impact clinical treatment.

Clinical Phenotype and Outcomes of Pulmonary Hypertension Associated with Myeloproliferative Neoplasms: A Population-based Study

Rationale: Precapillary pulmonary hypertension (PH) is a rare and largely unrecognized complication of myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF). Objectives: To describe characteristics and outcomes of MPN-associated PH. Methods: We report clinical, functional, and hemodynamic characteristics, classification, and outcomes of patients with PV, ET, or primary MF in the French PH registry. Measurements and Main Results: Ninety patients with MPN (42 PV, 35 ET, 13 primary MF) presented with precapillary PH with severe hemodynamic impairment, with a median mean pulmonary arterial pressure and pulmonary vascular resistance of 42 mm Hg and 6.7 Wood units, respectively, and impaired clinical conditions, with 71% in New York Heart Association functional classes III/IV and having a median 6-minute-walk distance of 310 m. Half of the patients were diagnosed with chronic thromboembolic PH (CTEPH); the other half were considered to have group 5 PH. MF was preferentially associated with group 5 PH, whereas PV and ET were generally related to CTEPH. Proximal lesions were diagnosed in half of the patients with CTEPH. Thromboendarterectomy was performed in 18 selected patients with high risk of complications (5 early deaths). Overall survival at 1, 3, and 5 years was 67%, 50%, and 34% in group 5 PH and 81%, 66%, and 42% in CTEPH, respectively. Conclusions: PH is a life-threatening condition potentially occurring in MPN. There are multiple mechanisms, with equal diagnoses of CTEPH and group 5 PH. Physicians should be aware that PH strongly affects the burden of patients with MPN, especially in group 5 PH, with unknown pathophysiological mechanisms.

Extramedullary Hematopoiesis: A Forgotten Diagnosis and a Great Mimicker of Malignancy

ABSTRACT

Radiology errors have been reported in up to 30% of cases when patients have abnormal imaging findings. Although more than half of errors are failures to detect critical findings, over 40% of errors are when findings are recognized but the correct diagnosis or interpretation is not made. One common source of error is when imaging findings from one process simulate imaging findings from another process but the correct diagnosis is not made. This can result in additional imaging studies, unnecessary biopsies, or surgery. Extramedullary hematopoiesis is one of those uncommon disease processes that can produce many imaging findings that may lead to misdiagnosis. The objective of this article is to review the common and uncommon imaging features of extramedullary hematopoiesis while presenting a series of interesting relevant illustrative cases with emphasis on CT.

Pulmonary hypertension is associated with poor cardiovascular and hematologic outcomes in patients with myeloproliferative neoplasms and cardiovascular disease

Cardiovascular events and hematologic progression to myelofibrosis or leukemia are leading causes of morbidity and mortality among patients with myeloproliferative neoplasms (MPN). Pulmonary hypertension (PH) is also associated with MPN and cardiovascular disease (CVD), though its prognostic significance in MPN is not well characterized. Our primary objective was to investigate the effect of PH, defined as right-ventricular systolic pressure (RVSP) ≥ 50 mmHg on echocardiogram or mean pulmonary artery pressure (mPAP) ≥ 20 on right heart catheterization, on cardiovascular and all-cause mortality and hematologic progression in patients with MPN and CVD (atrial fibrillation, heart failure hospitalization, and myocardial infarction after MPN diagnosis). Of the 197 patients included (86 ET, 80 PV, 31 PMF), 92 (47%) had PH and 98 (50%) were male. All-cause mortality (58 vs 37%, p = 0.004), cardiovascular death (35 vs 9%, p < 0.0001), and hematologic progression (23 vs 11%, p = 0.037) occurred more frequently in patients with PH. Multivariable competing-risk and proportional hazards regression showed that PH was associated with increased risk of all-cause death (adjusted hazard ratio [HR], 1.80, 95% CI 1.10-2.93), CV death (adjusted subdistribution HR 3.71, 95% CI 1.58-8.73), and hematologic progression (adjusted subdistribution HR 1.99, 95% CI 1.21-3.27).

Bilateral adrenal and pulmonary haemorrhages as an initial presentation of polycythaemia vera

We report a case of a man in his early 60s presenting with bilateral adrenal and pulmonary haemorrhages as an initial presentation of polycythaemia vera (PV). Symptomatology included severe compressive chest pain radiating to epigastrium, with unremarkable physical findings, parameters and ECG. Blood investigations showed an elevated haemoglobin (174 g/L, reference range (RR): 141-172g/L) and haematocrit (55.7%, RR: 40.4%-50.4%) levels.Cross-sectional imaging excluded aortic dissection, but imaging repeated 48 hours after his admission for acute dyspnoea and worsening abdominal pain showed bilateral alveolar and adrenal haemorrhages. Cortisol level was 27 nmol/L (RR: 145-619 nmol/L). Investigations confirming PV included the presence of a Janus kinase 2 (JAK2V617F) gene mutation, hypercellularity with erythroid hyperplasia on bone marrow microscopy and a low serum erythropoietin (2.6 mIU/mL, RR: 4.3-29.0 mIU/mL). Aspirin, hydroxyurea, venesection and cortisol replacement were initiated to get good treatment outcome.

Cardiovascular Disease in Myeloproliferative Neoplasms: JACC: CardioOncology State-of-the-Art Review

Myeloproliferative neoplasms are associated with increased risk for thrombotic complications. These conditions most commonly involve somatic mutations in genes that lead to constitutive activation of the Janus-associated kinase signaling pathway (eg, Janus kinase 2, calreticulin, myeloproliferative leukemia protein). Acquired gain-of-function mutations in these genes, particularly Janus kinase 2, can cause a spectrum of disorders, ranging from clonal hematopoiesis of indeterminate potential, a recently recognized age-related promoter of cardiovascular disease, to frank hematologic malignancy. Beyond thrombosis, patients with myeloproliferative neoplasms can develop other cardiovascular conditions, including heart failure and pulmonary hypertension. The authors review the pathophysiologic mechanisms of cardiovascular complications of myeloproliferative neoplasms, which involve inflammation, prothrombotic and profibrotic factors (including transforming growth factor-beta and lysyl oxidase), and abnormal function of circulating clones of mutated leukocytes and platelets from affected individuals. Anti-inflammatory therapies may provide cardiovascular benefit in patients with myeloproliferative neoplasms, a hypothesis that requires rigorous evaluation in clinical trials.

[Pulmonary Hypertension and Polycythemia vera]

INTRODUCTION

 Chronic myeloproliferative diseases are rare causes of PH class 5 according to Nice classification 2018. The present case reports show different courses, on the one hand with a primary manifestation of a PH and subsequently a PV, on the other hand with the development of a PH in the context of a PV.

CASE REPORTS

 1) At first contact, a 75-year-old female patient who complained progressive dyspnea and had evidence of stress-PH in the right heart catheter. During the course she developed a resting PH of up to 70 mmHg systolic despite initial monotherapy and subsequent dual therapy for PH. After 5 years she had the diagnosis of polycythemia vera, treated with hydroxycarbamide and subsequent phlebotomies. In the further course increasing cardiac decompensation and death. 2) 74-year-old female patient at the time of diagnosis of chronic megakaryocytic-granulocytic myelosis. After 7 years, evidence of polycythemia vera (V617F mutation in the JAK2 gene), a monoclonal gammopathy. In the case of splenomegaly, irradiation of the spleen was carried out and, after 1 year, therapy with ruxolitinib was started. After another 2 years, with increasing dyspnea, pulmonary hypertension (CTEPH) with a PA-mean of 43 mmHg and a PVR of 4.5 WE were detected. With anticoagulation and riociguat therapy exercise capacity and PA pressures were only temporarily improved. Within 1 year restrictive ventilation, hypoxemia, heart failure (EF 45 %) with leading right heart decompensation and cardiorenal syndrome developed. Dialysis showed only short-term recompensation, and the patient died.

DISCUSSION

 The case reports are characterized by a combination of PV and PH, with different temporal sequence, as well as only a low influence of PH-specific therapy, with subsequent progressive cardiac decompensation. Thus, they reflect the different etiologies, clinical manifestations, and the low therapeutic influence of PH in myeloproliferative disorders. The value of PH-specific therapy remains unclear, especially in view of different pathomechanisms in the genesis of PH.

CONCLUSION

 Patients with myeloproliferative diseases require screening for PH. In the course of PH, myeloproliferative disease can unmask or develop. The therapeutic influence on PH is limited.

Case of Pulmonary Extramedullary Hematopoiesis Responding to Ruxolitinib

We report a case of 43-year-old woman diagnosed with essential thrombocythemia in 1992. She was diagnosed with secondary myelofibrosis in 2011. Later, she suffered mild dyspnea, which gradually worsened. She was admitted to our hospital to evaluate the cause in 2014. Chest computed tomography showed ground-glass opacity (GGO) in the lungs. A lung biopsy revealed various hematopoietic cells, including abnormal megakaryocytes, infiltrating the alveolar septum, suggesting pulmonary extramedullary hematopoiesis. She was successfully treated by ruxolitinib and her disease is well controlled for more than 7 years. To keep this phenomenon in mind when see the patients with dyspnea is important.

Extramedullary hematopoiesis in myeloproliferative neoplasms: Pathophysiology and treatment strategies

Extramedullary hematopoiesis (EMH) is often a physiologic response to ineffective marrow production of hematologic cells. While this can be found incidentally in various physiologic and pathophysiologic states, the myeloproliferative neoplasms (MPNs) are some of the most common underlying conditions found in patients with EMH. Although this process can assist with hematologic production in defective states, the burden of EMH can lead to symptomatic discomfort and mechanical obstructive complications, most commonly in the spleen and liver. Here we describe the pathophysiology of EMH, treatment options, including medical, surgical and radiation-based approaches.

Evaluation of hemodynamic parameters among patients with myeloproliferative neoplasms and suspected pulmonary hypertension

Myeloproliferative neoplasms (MPNs) are associated with pulmonary hypertension (PH). We studied MPN patients who underwent right-heart-catheterization (RHC) to identify hemodynamic differences between MPN-subtypes. Per RHC, hemodynamics were classified as pre, post or combined pre and post-capillary PH. One-way analysis-of-variance (ANOVA) was used to compare hemodynamic differences among MPN-subtypes. Correlation of RVSP between trans-thoracic echocardiography (TTE) and RHC was evaluated. We included 68 patients. Median age was 63. Fifty-nine percent were male and 87% Caucasian. Polycythemia vera and essential thrombocythemia were the most common subtypes. On TTE, 91.5% had PH. On RHC, only 29% met criteria for pre-capillary PH. No MPN-subtype was more likely than others to have pre-capillary PH. Bland-Altman analysis showed significant intra-person variability between TTE and RHC-derived right ventricular systolic pressures. Post-capillary involvement is more common than precapillary PH in MPN. Type of PH does not appear to differ by MPN-subtype.

Pulmonary hypertension in patients with Philadelphia-negative myeloproliferative neoplasms: a single-center retrospective analysis of 225 patients

Background

The prevalence of pulmonary hypertension (PH) in myeloproliferative neoplasms (MPNs) varies among studies. We analyzed the prevalence of PH in Korean patients with Philadelphia-negative (Ph^-) MPNs.

Methods

Medical records of patients with Ph^- MPNs [essential thrombocythemia (ET), polycythemia vera (PV), or primary myelofibrosis (PMF)] visiting a single hospital between 1993 and 2019 were reviewed retrospectively. Transthoracic echocardiographic examination (TTE) results were reviewed and PH was diagnosed according to established guidelines.

Results

Of the 320 MPN (179 ET, 107 PV, and 34 PMF) patients, 225 (121 ET, 83 PV, and 21 PMF) underwent TTE. Of these 225 MPN patients, 19 of 121 (15.7%) ET, 9 of 83 (10.8%) PV, and 6 of 21 (28.6%) PMF patients had PH. PV patients with PH were older [71 (42‒85) vs. 61.5 (26‒91) yr, respectively; P=0.049], predominantly female (male:female ratio, 0.29 vs. 1.96, respectively; P=0.010), had lower hemoglobin levels (15.9±2.6 g/dL vs. 18.4±2.6 g/dL, respectively; P=0.010), and higher platelet counts (616.6±284.2×10⁹/L vs. 437.7±191.7×10⁹/L, respectively; P=0.020) than PV patients without PH. PMF patients with PH had higher monocyte counts (1.3±0.5×10⁹/L vs. 0.8±0.4×10⁹/L, respectively; P=0.031) than those without PH. PH was a risk factor for poor survival in PV (HR, 12.4; 95% CI, 1.8‒86.6).

Conclusion

PH is common in patients with Ph^- MPNs and hence, careful screening for PH is warranted.

A comparison of computed tomography with magnetic resonance imaging for the diagnosis of thoracic extramedullary hemopoiesis in patients with leukemia: A non-inferiority retrospective diagnostic study

At present, MRI is the primary choice of examination for the diagnosis of thoracic extramedullary hemopoiesis. When thoracic extramedullary hemopoiesis presents as posterior mediastinum masses in specific clinical contexts, the diagnosis is not challenging. Other radiological presentations may be more difficult for diagnosis and require biopsy. Needle biopsy is typically preferred for the diagnosis of extramedullary hemopoiesis however, the high vascularization of tissues is one of the complications of this method thus, it is avoided. The aim of the present study was to compare the diagnostic parameters of CT with MRI for the diagnosis of thoracic extramedullary hemopoiesis in patients with leukemia, with an open lung biopsy as a reference standard. Chest CT, chest MRI and open lung biopsy data from a total of 912 patients with leukemia with a sign(s) and symptoms of suspected paravertebral and/or pulmonary extramedullary hemopoiesis were reviewed. In the present study, thoracic extramedullary hemopoiesis was defined as diffusivity of both lung fields being increased compared with the blood pool and no other abnormal focal of lungs being increased compared with the blood pool. The beneficial score was calculated for CT and MRI and plotted for the decision making of irradiation. With respect to open lung biopsy, MRI had a higher sensitivity compared with CT (0.865 vs. 0.809; P<0.0001; q=1691) however, CT had a higher accuracy compared with MRI (0.833 vs. 0.733; P<0.0001; q=3020). The low rate of overdiagnosis was observed for both methods for the detection of thoracic extramedullary hemopoiesis however, the working area for detecting thoracic extramedullary hemopoiesis at least once in images was higher for MRI compared with CT. CT and MRI both have diagnostic importance in the detection of thoracic extramedullary hemopoiesis in patients with leukemia however, chest MRI misdiagnoses the condition while CT can confirm it (level of evidence, 3).

Marrow outside marrow: imaging of extramedullary haematopoiesis

Extramedullary haematopoiesis (EMH) refers to the formation of non-neoplastic blood cell lines outside the bone marrow and is a common incidental finding when patients with haematological disorders are imaged. EMH presenting as mass (tumefactive EMH) has long been a radiological conundrum as it resembles neoplasms. Several imaging findings have been described in EMH, and these vary depending on the activity of the underlying haematopoiesis. The older lesions are easier to diagnose as they often demonstrate characteristic findings such as haemosiderin and fat deposition. In comparison, the newer, actively haematopoietic lesions often mimic neoplasms. Molecular imaging, particularly ^99mTc labelled sulphur colloid scintigraphy, may be helpful in such cases. Although imaging is extremely useful in detecting and characterising EMH, imaging alone is often non-diagnostic as no single mass shows all the typical findings. Hence, a judgement based on the clinical background, combination of imaging findings, and slow interval growth may be more appropriate and practical in making the correct diagnosis. In every case, an effort has to be made in providing an imaging-based diagnosis as it may prevent a potentially risky biopsy. When confident differentiation is not possible, biopsy has to be resorted to. This article describes the causes, pathophysiology, and theories underlying the genesis of EMH, followed by the general and location-specific imaging findings. The purpose is to provide a thorough understanding of the condition as well as enable the clinical radiologist in making an imaging-based diagnosis whenever possible and identify the situations where biopsy has to be performed.

Pulmonary hypertension is associated with increased nonrelapse mortality after allogeneic hematopoietic cell transplantation for myelofibrosis

Allogeneic hematopoietic cell transplantation (alloHCT) is the only curative therapy for primary myelofibrosis (MF) as well as myelofibrosis secondary to other myeloproliferative neoplasms (MPN). Pulmonary hypertension (PH) is a known complication of MF and may occur in up to 50% of such patients. PH (defined as a mean pulmonary artery pressure ≥25 mmHg at rest) can eventually lead to right heart failure and may be associated with complications after alloHCT. We examined the association of PH with alloHCT outcome in patients with MF associated with MPN. Pre- and post-HCT echocardiograms were reviewed to estimate the peak pulmonary artery systolic pressure (PASP). Median PASP was 37.0 mmHg (range: 16.0-57.9) prior to HCT with 37 of 65 patients (57%) studied. With median follow-up of 35.0 months (range: 3.3-119.4) PH was significantly associated with inferior OS (58.9% vs. 88.8%, P = 0.025), primarily due to increased NRM (21.6% vs. 7.1%, P = 0.007). The majority of the deaths (8 of 14) in patients with PH occurred within 100 days after HCT. In patients with an available post-HCT echocardiogram (n = 33), the median PASP was 30 mmHg (range: 5.0-56.2); eight patients (24%) had persistent PH. Compared with pre-HCT values, PASP was significantly reduced after HCT (p < 0.001). We conclude that PH is associated with inferior survival due to the increased NRM in patients with MF undergoing alloHCT. PH appears at least partially reversible after successful alloHCT. PH should be considered a risk factor for early mortality after alloHCT and surveillance of pulmonary artery pressure in MF patients being considered for alloHCT may be useful.

Medical Management of Pulmonary Hypertension with Unclear and/or Multifactorial Mechanisms (Group 5): Is There a Role for Pulmonary Arterial Hypertension Medications?

PURPOSE OF REVIEW

The purpose of this review was to outline the mechanisms and to review recent literature on pulmonary arterial hypertension (PAH) medications in group 5 pulmonary hypertension (PH).

RECENT FINDINGS

The first steps in management are to understand the mechanisms and hemodynamic profile and to exclude chronic thromboembolic disease. Recent studies in the past 5 years have found that PAH medications may improve hemodynamics in patients with pre-capillary pulmonary hypertension due to sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, and myeloproliferative disorders with dasatinib-induced PH. Improvements in exercise capacity are uncommon, and no survival benefit has been demonstrated. There is a risk of pulmonary edema in patients with pulmonary venous involvement or fibrosing mediastinitis when treated with PAH therapies. There is limited evidence supporting the use of PAH medications in group 5 patients, and they may be harmful in certain cases. In most patients with group 5 PH, treatment should be directed to the underlying disease with PAH therapies reserved for patients with severe pre-capillary PH.