Hypereosinophilia is a rare condition, defined as a persistent elevation of absolute eosinophil count greater than 1.5x109/L and/or tissue eosinophilia. This condition can be caused by numerous different etiologies, both hematological (clonal) and non-hematological (reactive). Reactive hypereosinophilia encompasses all disorders, including infections. Patients with hypereosinophilia may experience a spectrum of clinical consequences due to multiple organ damage, including neurologic and thrombotic complications, associated with organ dysfunction and potentially life-threatening sequelae. Cerebral venous thrombosis (CVT) is the term used to describe thrombotic occlusion of veins and/or venous sinuses in the brain. This condition can occur at all ages and CVT related to hypereosinophilia is a rare disease. Diagnosis of the disease must be done quickly because thrombosis causes blockage of cerebral drainage, venous congestion, disruption of cerebrospinal fluid reabsorption, ischemic neuronal damage, cerebral edema, and hemorrhage, leading to severe neurological complications. Management of intracranial hemorrhage from CVT due to hypereosinophilia is a challenging task for clinicians, based on anticoagulation therapy, systemic corticosteroid, management of elevated intracranial pressure, and potentially progressive hemorrhage due to anticoagulant. The outcome of the patient generally relies on early detection, prompt, and appropriate treatment. In this case report, we discuss a rare case of CVT with hypereosinophilia and positive dengue serology in a child, in the context of intracranial hemorrhage, enlightening the importance of considering a personalized strategy in the management of this complex scenario.

Hypereosinophilic syndrome (HES) encompasses a heterogeneous and complex group of different subtypes within the wider group of hypereosinophilic disorders. Despite increasing research interest, several unmet needs in terms of disease identification, pathobiology, phenotyping, and personalized treatment remain to be addressed. Also, the prospective burden of non-malignant HES and, more in general, HE disorders is currently unknown. On a practical note, shortening the diagnostic delay and the time to an appropriate treatment approach probably represents the most urgent issue, even in light of the great impact of HES on the quality of life of affected patients. The present document represents the first action that the Italian Society of Allergy, Asthma, and Clinical Immunology (SIAAIC) has finalized within a wider project aiming to establish a collaborative national network on HES (InHES-Italian Network on HES) for patients and physicians. The first step of the project could not but focus on defining a common language as well as sharing with all of the medical community an update on the most recent advances in the field. In fact, the existing literature has been carefully reviewed in order to critically integrate the different views on the topic and derive practical recommendations on disease identification and treatment approaches.

Here, we reviewed clinical-morphological data and investigated mutational profiles by NGS in a single-center series of 28 consecutive patients admitted to our hospital between September 2011 and November 2021 for idiopathic hypereosinophilia (HE).Bone marrow (BM) morphology was evaluated in 22 patients: while in six subjects BM was unremarkable, in the remaining cases an increase in BM eosinophils was observed, together with a slight increase in BM fibrosis (MF-1) in 5/22 patients.A total of 4/28 patients had at least one genetic lesion by targeted NGS. In particular, the genes involved were: two each of TET2 and DNMT3A; and one each of JAK2V617F, ASXL1, PPM1D, and ZBTB33. Notably, JAK2V617F and TET2 mutations co-occurred, with the JAK2V617F-mutated sample also carrying TET2 lesions. Median VAF was 21%, with the exception of the oncodriver JAK2V617F, which showed a VAF > 50% in the reported case. Of note, of the four cases bearing lesions, 2/4 had multiple hits in different genes.While in recent years mutational analysis using NGS has proven to be able to differentiate clonal hematopoietic neoplasms from reactive processes in diagnostically difficult cases, we found somatic mutations in only 14.3% of patients who acceded to our hospital for idiopathic HE. More importantly, excluding the JAK2V617F-mutated case with an underlying MPN-Eo diagnosis, NGS was able to identify somatic mutations in only three cases, all older than 70 years. Consequently, the detection of these mutations in idiopathic HE patients should be interpreted with caution and only in the context of other supportive clinical-pathological findings.

OBJECTIVE: In this review, we aim to explore the optimal approach to patients presenting with eosinophilia, considering recent advances in diagnostic and therapeutic strategies. Specifically, we focus on the integration of novel therapies into clinical practice to improve patient outcomes.
RESULTS: Advanced insights into the clinical and genetic features of eosinophilic disorders have prompted revisions in diagnostic criteria by the World Health Organization classification (WHO-HAEM5) and the International Consensus Classification (ICC). These changes reflect a growing understanding of disease pathogenesis and the development of targeted treatment options. The therapeutic landscape now encompasses a range of established and novel therapies. For reactive conditions, drugs targeting the eosinophilopoiesis, such as those aimed at interleukin-5 or its receptor, have demonstrated significant potential in decreasing blood eosinophil levels and minimizing disease flare-ups and relapse. These therapies have the potential to mitigate the side effects commonly associated with prolonged use of oral corticosteroids or immunosuppressants. Myeloid and lymphoid neoplasms with eosinophilia and tyrosine kinase (TK) gene fusions are managed by various TK inhibitors with variable efficacy. Diagnosis and treatment rely on a multidisciplinary approach. By incorporating novel treatment options into clinical practice, physicians across different disciplines involved in the management of eosinophilic disorders can offer more personalized and effective care to patients. However, challenges remain in accurately diagnosing and risk-stratifying patients, as well as in navigating the complexities of treatment selection.

Left ventricular thrombus (LVT) has historically been reported as a complication of acute left ventricular (LV) myocardial infarction. It is most commonly observed in cases of LV systolic dysfunction attributed to ischemic or nonischemic etiologies. Conversely, the occurrence of LVT in normal LV systolic function is an exceptionally rare presentation and is predominantly associated with conditions such as hypereosinophilic syndrome (HES), cardiac amyloidosis, left ventricular noncompaction, hypertrophic cardiomyopathy (HCM), hypercoagulability states, immune-mediated disorders, and malignancies. Notably, hypereosinophilia (HE) has been linked with thrombotic events. Intracardiac thrombus is a well-known complication of eosinophilic myocarditis (EM) or Loeffler endomyocarditis, both of which are considered clinical manifestations of HES. We present a case of a 63-year-old male with normal LV systolic function, HE, and noncontributory hypercoagulability workup, who presented with thromboembolic complications arising from LVT. Interestingly, the diagnostic evaluation for EM and Loeffler endocarditis was nonconfirmatory. Additionally, we performed a literature review to delineate all similar cases. This article also outlines the pathophysiology, diagnosis, and treatment approaches for hypereosinophilic cardiac involvement with a specific focus on LVT.

Hypereosinophilia is a rare presentation in all age groups, particularly when it is severe, persistent, and progressive. We describe the clinical characteristics and course of severe hypereosinophilia in a full-term Saudi female neonate. A febrile respiratory illness evolved with a progressive increase in peripheral blood leukocyte and eosinophil counts, reaching 44.9% of leukocytes and an absolute value of 57,000 cells/µl. Different etiological examinations (for viral, bacterial, immunodeficiency, hyper IgE syndrome, gene mutations) revealed extremely high CMV antigenemia and a homozygous mutation in the STAT1 gene. Anhelation was relieved by oxygen and anti-viral treatment. Steroids brought a dramatic response in peripheral blood counts within 24 h. After a 6-week course of antiviral and steroid treatment at home, she had an excellent general condition. Conclusion: Although a rare pathology, it is important to consider genetic disorders when there is an atypical immune response to viral infections.

UNASSIGNED: Hypereosinophilic Syndrome (HES) is a rare disorder characterized by persistent elevation of eosinophils, leading to multi-organ infiltration and damage. Eosinophilic Myocarditis (EM) is one of its severe complications contributing significantly to morbidity and mortality. Herein, we describe the diagnostic and therapeutic challenges of EM, emphasizing the significance of early recognition and multidisciplinary management.
UNASSIGNED: A 51-year-old female with a history of EM, heart failure, and peripheral eosinophilia presented with NYHA class 3b symptoms. Laboratory findings revealed elevated peripheral eosinophil count, NT-Pro BNP, and characteristic electrocardiogram abnormalities. Imaging studies confirmed biventricular thrombi and myocardial abnormalities consistent with EM. Treatment involved Solu-Medrol for HES and heparin for ventricular thrombi, leading to initial clinical improvement. However, refractory heart failure necessitated urgent heart transplantation.
UNASSIGNED: EM, an under-recognized complication of HES, poses diagnostic and management challenges. Management includes standard heart failure treatments, steroids, and emerging therapies like Mepolizumab. Early diagnosis and aggressive management are pivotal for improving outcomes in this rare and potentially fatal condition.
UNASSIGNED: Advancements in the detection of complications, surgical management, and therapeutic options have improved outcomes in HES. Ongoing research is essential to further understand and address the diagnostic and therapeutic challenges of HES and EM.

Hypereosinophilic syndrome (HES) is a rare condition characterized by elevated eosinophil counts (>1.5 x 109 on two consecutive measurements), which are of myeloid clonal in origin or are driven by excess cytokines. One subtype of HES exhibits the Fip1-like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) fusion gene, a gain-of-function mutation resulting in a hyperactive tyrosine kinase. HES, especially the FIP1L1-PDGFRA variant, exhibits an excellent response to chemotherapy with imatinib. In this report, we present a 38-year-old patient with no contributory past medical history who experienced sudden-onset fatigue, ataxia, visual changes, and headaches. He was found to have multiple small acute infarcts in his cerebrum and cerebellum. A stroke work-up, including transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), and computed tomography angiography (CTA), did not yield insight into the origin of his infarcts. On CBC, he was consistently hypereosinophilic, and a bone marrow biopsy revealed hypercellularity and the FIP1L1-PDGFRA fusion gene, confirming the diagnosis of HES. The patient was treated first with methylprednisolone and then imatinib with excellent response. It appears that, in our patient, strokes were not of a thromboembolic nature but rather due to hypercoagulability. In this report, we advocate for considering HES and emphasize the importance of revisiting basic laboratory studies such as a CBC if the standard stroke workup fails to elucidate the mechanism behind ischemic strokes with an embolic pattern.

The report explores a case of cerebral sinus venous thrombosis associated with hypereosinophilia, presenting a unique clinical scenario. A 22-year-old male presented with persistent headache for eight days, escalating in intensity, along with projectile vomiting and blurred vision. Despite the absence of typical indicators such as fever or respiratory symptoms, comprehensive evaluations revealed hypereosinophilia in the complete blood count. Imaging studies, including magnetic resonance angiography and venography, confirmed cerebral sinus venous thrombosis. The patient was successfully treated with a multidimensional approach, including anticoagulation therapy, corticosteroids, and supportive measures. This report highlights the concealed nature of hypereosinophilia in the context of cerebral sinus venous thrombosis and underscores the importance of a vigilant diagnostic approach in unravelling this silent association.

Type 2 inflammation is a heterogeneous condition due to the complex activation of different immunological pathways. Rapid progress in research to evaluate the efficacy of biologics for chronic rhinosinusitis with nasal polyps and asthma has led to the availability of effective therapeutic options. These drugs are safe, but temporary iatrogenic hypereosinophilia may sometimes be associated with clinical symptoms or organ damage. Here, we describe a case of severe hypereosinophilia in a patient with chronic rhinosinusitis with nasal polyps and asthma treated with dupilumab and a subsequent therapeutic shift to mepolizumab that led to maintenance of symptom control and concomitant normalization of blood eosinophil count.