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Rosai-Dorfman Disease (RDD) is an uncommon histiocytic disorder that can affect lymph nodes and/or extranodal sites. It is marked by the accumulation of abnormal histiocytes that demonstrate emperipolesis—the active, non-destructive engulfment of other leukocytes. RDD exhibits considerable variability in clinical presentation, pathology, genetics, treatment response, and patient outcomes. In this report, we describe 2 rare cases of RDD that underwent sarcomatous transformation and harbored MAP2K1 mutations, both of which demonstrated poor responses to multiple lines of therapy. Additionally, we review 3 other similar cases from the literature.

Background/Objectives: Standard treatment of multiply relapsed Ewing sarcoma remains to be established. Recent studies evaluating tyrosine kinase inhibitors (TKIs) with anti-angiogenic properties have shown encouraging results. Therefore, we conducted a systematic review and meta-analysis to explore the efficacy and safety of TKIs in patients with Ewing sarcoma. Methods: We comprehensively searched PubMed, Embase, and Cochrane databases for clinical trials (CTs) and cohort studies assessing TKIs in the treatment of advanced Ewing sarcoma patients who received at least one prior line of therapy. The main outcome was objective response rate (ORR). All analyses were conducted using R software (v.4.2.2), employing random effects models with 95% confidence intervals (CIs). Results: We included 14 studies (seven phase II CT and seven retrospective cohorts), comprising 257 patients. The following TKIs were evaluated: cabozantinib, regorafenib, apatinib, anlotinib, sorafenib, lenvatinib, sunitinib, fruquintinib, and imatinib. In a pooled analysis of all Ewing sarcoma patients treated with TKIs, the ORR was 23% (95% CI, 11.2–37.1%) and the DCR was 61.1% (95% CI, 47.3–74.2%). Responses were numerically higher but statistically nonsignificant between clinical trials and real-world studies. The analysis including only single-agent TKIs showed better responses for anlotinib and apatinib, yet these drugs are not available in Western countries. Among the FDA-approved TKIs, superior outcomes were noted with single-agent cabozantinib. (ORR: 21.6%) and regorafenib (ORR: 11.3%). Several studies did not report toxicity data exclusively for Ewing sarcoma patients; thus, conclusions about toxicity are mostly based on the general population of studies and may not be fully representative of Ewing sarcoma patients. Conclusions: Anti-angiogenic TKIs have shown important anti-tumoral activity in patients with Ewing sarcoma. Efficacy was consistently seen in both clinical trials and real-world studies. Nonetheless, there are important differences in study design and population that may limit our interpretation of efficacy and toxicity findings.

Hypertension has been traditionally known to be highlighted by mean blood pressure; however, emerging evidence exhibits that blood pressure variability (BPV), including short-term, day-to-day, and visit-to-visit fluctuations can have an implication across multiple body systems. Elevated BPV reflects repetitive hemodynamic stress, affecting the physiologic hemostasis contributing to vascular injury and end organ damage. This narrative review is a compilation of recent evidence on the prognostic value of BPV, explained by pathophysiology, various devices with its measurement approaches, and, essentially, the clinical implication of BPV and the use of such devices utilizing artificial intelligence. A comprehensive literature search across PubMed, Cochrane Library, Scopus, and Web of Science were conducted, focusing on observational studies, cohorts, randomized trials, and meta-analyses. Higher BPV has been associated with an increased risk of cardiovascular mortality, stroke, coronary events, and heart failure, the progression of chronic kidney disease, cognitive decline, and preeclampsia, among other end organ damage, despite mean blood pressure. The various pathophysiologic mechanisms include autonomic dysregulation, arterial stiffness, endothelial dysfunction, circadian rhythm alteration, and systemic inflammation, which result in vascular remodeling and multisystem damage. Antihypertensive medications such as calcium channel blockers and renin–angiotensin–aldosterone system inhibitors seem to reduce BPV; randomized trials have not specifically investigated their BPV-reducing effects. The aim of this review is to highlight that BPV is a dynamic marker of multisystem risk, and question how various AI-based devices can aid continuous BPV monitoring and patient specific risk stratification.

Background: Patients with cervical artery dissection (CAD) have a higher prevalence of cerebral aneurysms, likely due to underlying vasculopathies. Understanding risk factors and outcomes in this population may inform screening and management strategies. Methods: We conducted a post-hoc analysis of the STOP-CAD study, a multicenter international registry of patients with non-major trauma-related CAD across 63 centers. Cerebral aneurysms were identified based on medical history and intracranial vascular imaging obtained for dissection diagnosis. We compared demographic, clinical, laboratory, and imaging characteristics between patients with and without aneurysms. Variables with p<0.05 in univariate analysis were entered into a multivariable binary logistic regression to identify independent predictors. Clinical outcomes including ischemic stroke and symptomatic intracranial hemorrhage at follow-up were compared between both groups. Results: Out of 4023 patients included in the STOP-CAD study, 116 (2.9%) had at least one incidental cerebral aneurysm. In adjusted binary logistic regression, patients with cerebral aneurysm were more likely to have a history of migraine (aOR 1.78 95% CI 1.15-2.75, p=0.009), history of hypertension (aOR 1.65 95% CI 1.12-2.43, p = 0.010), known connective tissue disorder (aOR 3.47 95% CI 1.71-7.03), history of dissection (aOR 2.63 95% CI 1.31-5.28, p = 0.007), and a dissecting aneurysm at the site of the dissection (aOR 1.94 95% CI 1.25-3.01, p = 0.003). At follow-up, the presence of a cerebral aneurysm was not associated with ischemic stroke (7.8% vs. 5.6% p>0.1), but with a trend towards increased odds of symptomatic intracranial hemorrhage (3.4% vs. 1.2%, p = 0.062). Conclusions: Patients with CAD and concurrent incidental cerebral aneurysm were more likely to have a history of migraine headaches and markers of underlying vasculopathy and had a non-significantly increased risk of intracranial hemorrhage at follow-up. Further studies are needed to identify best practices for surveillance and risk stratification in this subgroup.

Background: The optimal role of advanced cardiac imaging in embolic stroke of undetermined source (ESUS) remains unclear. We hypothesized that advanced imaging would provide greater diagnostic utility than transthoracic echocardiography with bubble study (bTTE). Methods: We retrospectively analyzed adults ≥18 years admitted with ESUS/cryptogenic stroke or recurrent embolic stroke with known atrial fibrillation (Aug 2024–Aug 2025). Patients with incomplete workup or known stroke mechanism prior to advanced imaging were excluded. Transesophageal echocardiography (TEE), cardiac MRI (CMRI), or CT heart morphology (CTH) were considered diagnostic if thrombus, patent foramen ovale (PFO), aortic plaque, or valvular pathology was detected. Outcomes included (1) etiology determination, (2) management change, and (3) diagnostic yield comparison between bTTE and advanced imaging. Results: Of 588 ischemic strokes, 178 met inclusion criteria; 48 were excluded for incomplete workup. Among 130 eligible patients, 65 (50%) underwent advanced imaging (40 TEE, 19 CTH, 6 CMRI). Etiology was identified in 41.5% (95% CI 30–54%), and management was changed in 40.0% (95% CI 29–52%). Compared with bTTE alone (14.6% yield), advanced imaging identified additional etiologies in 42.9% (McNemar p<0.001). Advanced imaging was more frequently performed in younger patients (mean 59.6 vs 69.2 years, p<0.001), while posterior circulation strokes were associated with higher odds of positive findings (OR 5.25, 95% CI 1.01–27.2). Conclusions: Advanced cardiac imaging identified a potential etiology and changed management in ~40% of ESUS/cryptogenic strokes, significantly outperforming bTTE. Although younger patients more often underwent advanced imaging in this cohort, only posterior circulation strokes predicted clinically actionable findings. Routine incorporation of advanced cardiac imaging into ESUS evaluation may improve diagnostic accuracy and treatment decisions.

Background: Cervical artery dissection (CeAD) accounts for nearly 25% of all ischemic strokes in young adults. CeAD can lead to the development of dissecting aneurysms (DA). However, the incidence, risk factors and outcomes of CeAD patients with DA is not well established. This study aims to identify risk factors for developing DA, subsequent growth, and impact on patient outcomes. Methods: This is a secondary analysis of the Antithrombotics for Stroke Prevention in Cervical Artery Dissection (STOP-CAD), a multicenter cross-sectional international retrospective study. CeAD patients were stratified for the presence of DA. We used multivariable regression to identify factors associated with DA. Patients with DA were further analyzed for DA growth. The primary outcome was ischemic stroke after CeAD+DA diagnosis. Secondary outcomes included ischemic stroke after CeAD+DA with DA growth. Multivariable logistic regression analysis was used to assess the association between DA and risk factors. We also performed univariate Cox regression and generated Kaplan-Meier survival curves comparing study outcomes based on presence of DA and subsequent growth. Results: Of the 4023 patients included in the STOP-CAD study, 4008 were included in this analysis and 767 (19%) patients had DA (546 with DA on initial presentation). Patients with DA had a mean age of 46 [IQR 37-55] years and 50% (383) were women. In combined adjusted analyses, DA patients were more often non-Hispanic (aOR 0.63, 95% CI 0.41-0.94, p<0.02), more commonly had a history of migraine (aOR 1.27, 95% CI 1.01-1.59, p=0.037), connective tissue disorder (aOR 2.02, 95% CI 1.22-3.36, p=0.007), minor neck trauma (aOR 1.70, 95% CI 1.29-2.26, p<0.001) and were more likely to present with ischemic stroke (aOR 1.73, 95% CI 1.05-2.87, p=0.031). DA growth was noted in 55 out of 546 (10%) patients with DA on presentation. There was no significant difference in the risk of ischemic stroke by day 180 in patients with DA (hazard ratio [HR] 0.92 [95% CI, 0.65-1.30]; P =0.63) or DA growth (HR 2.40, [95% CI, 0.79-7.24]; P =0.12). Conclusion: In this subanalysis of STOP-CAD, nearly one in five patients with CeAD developed a DA. Factors associated with a higher likelihood of DA included non-Hispanic ethnicity, history of migraine, connective tissue disorder, minor neck trauma, and ischemic stroke at presentation. DA diagnosis and DA growth did not impact the risk of subsequent ischemic stroke at 6 months.

Introduction: Optimizing patient selection and time-to-intervention will be crucial to the success of future clinical trials seeking to implement therapies and improve intracerebral hemorrhage (ICH) patient outcomes. Automated and accurate ICH and perihematomal edema (PHE) volumetry carries significant potential to strengthen trials targeting ICH and PHE expansion. Aims: The Quantification of Hematoma and Perihematomal Edema Volumes in Intracerebral Hemorrhage (QUANTUM) trial was designed with aims of (1) validating a fully automated artificial intelligence (AI) method for supratentorial, spontaneous ICH and PHE volumetry against the manual and semiautomated quantification methods and (2) establishing a model framework for the translation of AI technology through conduct of a clinical trial under the equivalence hypothesis paradigm. Methods: This trial was a prospective, randomized, clinical study with blinded outcome assessment. Six independent raters were randomized in a 1:1 ratio to ICH and PHE volumetry from non-contrast CT scans in the Virtual International Stroke Trials Archive with either the semiautomated or manual quantification method. The primary outcomes were equivalence between (1)ICH volume measurements on admission (<24h from symptom onset) for the manual versus the fully automated or the sem-automated quantification methods, and (2)PHE volume measurements on day 3 (72±12h from symptom onset) for the manual versus the fully automated or the semiautomated quantification methods. The required sample size was 126 ICH and 126 PHE measurements, based upon a significance level of 0.025 to account for the two equivalence tests. Results: The geometric mean relative discrepancies between the fully automated and the manual ICH and PHE volume measurements did not cross the pre-specified 10% equivalence margin. The geometric mean relative discrepancies between the semiautomated and the manual ICH and PHE volume measurements did cross the pre-specified 10% equivalence margin. The fully automated method (mean 10.0±2.7s/scan) was significantly faster than the manual (mean 189±199 s/scan; P <0.001) and semiautomated (mean 79±68s/scan; P <0.001) methods. Conclusions: ICH and PHE volumes quantified by AI could replace clinician measurements within a 10% error margin and with substantially greater efficiency. The semiautomated method could not replace manual measurements. This trial demonstrated feasibility of the equivalence hypothesis framework for AI validation studies.

Background: The clinical characteristics and complications associated with de novo pseudoaneurysm formation beyond the acute phase of cervical artery dissection remain poorly defined. In this study, we examined the incidence, risk factors, and related ischemic and hemorrhagic events of post-acute de novo pseudoaneurysm formation. Methods: We analyzed data from the STOP-CAD study (Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection). A de novo pseudoaneurysm was defined as a new (not present on initial imaging) focal enlargement in the diameter of the artery, greater than the native lumen. The incidence of de novo pseudoaneurysm was assessed at 90 days, 180 days, and beyond 180 days of follow-up. Univariate and multivariate regression analyses were conducted to identify risk factors for post-acute de novo pseudoaneurysm formation. Kaplan-Meier survival estimates were used to compare ischemic and hemorrhagic events between patients with and without de novo pseudoaneurysms. Results: Among 4008 patients, 546 were excluded as they had dissecting pseudoaneursyms on initial presentation. Therefore, 3,462 patients were included in this analysis of whom 220 patients (6.35%) developed a de novo pseudoaneurysm over a maximum follow-up of 4.4 years. Of these, 127 (57.72%) were detected within the first 90 days, and 172 (78.18%) within the first 180 days. In multivariate regression analyses, in addition to hypertension, active smoking and Hispanic ethnicity, fibromuscular dysplasia (FMD) was an independent risk factor for post-acute de novo pseudoaneurysm formation (adjusted OR: 2.160; 95% CI: 1.408–3.315; p < 0.001). Notably, the presence of a de novo pseudoaneurysm was not associated with a significant increase in ischemic (hazard ratio [HR] 1.43 [95% CI, 0.89–2.30]; P=0.14) or hemorrhagic events (hazard ratio [HR] 1.42 [95% CI, 0.43–4.69]; P=0.57). Conclusion: De novo pseudoaneurysm formation following a diagnosis of a cervical artery dissection is not uncommon and most frequently occurs within the first 180 days. FMD was independently associated with this complication. The development of a de novo pseudoaneurysm did not significantly increase the risk of subsequent ischemic or hemorrhagic events.

Introduction: Embolic stroke of undetermined source (ESUS) is a clinical construct encompassing heterogenous possible mechanisms of incident stroke, potentially with variable responsiveness to anticoagulation and antiplatelet treatment. This study aims to identify differences in recurrent stroke risk based on phenotypic clusters in an ESUS population, and whether some clusters may benefit relatively more from anticoagulation over antiplatelet therapy. Methods: We identified patient phenotypes from a multicenter, retrospective cohort study of 1909 ESUS patients by dividing them into groups using Partitioning Around Medoids (PAM) with correlation-weighted Gower distance over 23 baseline demographic, clinical, laboratory, radiographic, and cardiac features. We confirmed optimal clustering at 3 groups. We assessed cluster associations with time to recurrent stroke using Kaplan-Meier survival analysis. We then employed a causal survival forest to estimate conditional average treatment effects (CATE) of anticoagulation versus antiplatelet therapy using the same baseline features as predictors with a 365-day horizon for restricted mean survival time differences. Finally, we used best linear projection to identify baseline features predictive of treatment effect and assessed whether effects differed significantly by cluster. Results: Cluster 1 (n=542) identified a low-risk, younger sample with minimal baseline disability and comorbidity burden. Cluster 2 (n=743) comprised a moderate-risk phenotype with intermediate comorbidity. Cluster 3 (n=626) represented the oldest and highest-risk phenotype. Kaplan-Meier analysis demonstrated significant differences in stroke-free survival across patient clusters (p < 0.001), where Cluster 1 experienced the lowest recurrent stroke rate and Cluster 3 had the highest. The clustering algorithm successfully identified clinically meaningful phenotypes with distinct risk profiles. While CATE varied across clusters, the differences were not statistically significant. Conclusion: In a multicenter ESUS population, we identified 3 distinct phenotypic clusters, each comprising nearly one-third of the sample and with a differential risk of recurrent stroke. Although cluster was not a significant effect modifier, substantial CATE variability by cluster was observed. Future clinical trials may consider evaluating secondary stroke prevention therapies among phenotypically similar patients who may respond differentially to novel therapies.

Background: Interfacility transfers, especially in rural settings, present challenges including limited ambulance availability, bed capacity, image sharing and disparities in access. Regional transfer minimizes time to definitive stroke center care, relies less on costly helicopter transport, supports local healthcare economies, and preserves comprehensive stroke center (CSC) resources for those most likely to benefit. Although these advantages are well-established and reflected in the guidelines, transfers within our connected care rural network were not previously accepted at hospitals outside of our central comprehensive stroke center (CSC). Methods: We identified a local primary stroke center to serve as the regional stroke transfer center (rSTC) within our larger telestroke network. Over one year, (2023-2024), stakeholder meetings with representatives from the rSTC, surrounding smaller hospitals and the CSC were conducted to pinpoint potential roadblocks and create workflows that facilitated regional transfer. Regionally appropriate transfers were defined as patients without LVO, low likelihood for any neurosurgical decompression, or critical illness requiring dedicated neuro-intensive care. Education surrounding these criteria occurred quarterly and case logs were maintained and reviewed by the rSTC stroke coordinator. Retrospective chart review one year following the intervention period (2024-2025) was performed. Results: Of the 99 total transferred patients, 73 (73.7%) patients were transferred regionally. Their average LOS was 2.1 days, with 0% mortality rate and 0% requiring a secondary transfer to the CSC. 26 (26.3%) patients went to the CSC; LOS was 10.6 days and mortality 23.1%. Transfer times were shorter for rSTC patients (60 min vs 188 min). Six CSC patients met regional criteria (26.3% overtriage rate). Conclusion: Establishing an effective regional transfer model is possible with broad stakeholder engagement and regular network maintenance. Following our intervention, most eligible patients remained local and were treated appropriately. Although there was a significant reduction of the patients transferred to the CSC, the majority of CSC transfers were also appropriately triaged. This rSTC model facilitates the care of all stroke patients by providing the right level of care for the right patient, avoiding futile transfers with costly admissions far from home while opening beds and reducing transfer times to CSCs.