Citations

Abstract Autoinflammatory syndromes are increasingly recognized as heterogeneous disorders of innate immune dysregulation, often overlapping in clinical and genetic features. Although pulmonary manifestations are uncommon, several autoinflammatory conditions such as VEXAS syndrome, juvenile rheumatoid arthritis, adult-onset Still’s disease, and Familial Mediterranean Fever can produce inflammatory pulmonary nodules that mimic metastatic malignancy. Recognition of these presentations is critical, as they can respond dramatically to immunosuppressive therapy once the correct diagnosis is established. We describe a diagnostically challenging case of a young adult male initially suspected to have metastatic lung cancer, whose evaluation ultimately suggested a previously uncharacterized autoinflammatory process. We present a 26-year-old previously healthy male with progressive dry cough, exertional dyspnea, diffuse myalgias, small joint arthritis involving the fingers, wrists, and ankles, tendonitis, a Gottron-like rash on the hands and lower extremities, low-grade fevers, and occasional bloody stools. Initial external workup revealed a right infrahilar mass, right lower lobe pleural thickening, small pleural effusion, and mediastinal and hilar lymphadenopathy on CT chest, with corresponding PET activity. Initially suspected to have metastatic lung cancer, he was informed his prognosis was poor. However, transbronchial, EBUS, and mediastinal lymph node biopsies showed only active inflammation without malignancy. On presentation to our facility, a broad differential was pursued, with suspicion for an autoinflammatory or autoimmune etiology. Pulmonary function testing was normal. Laboratory evaluation revealed ESR >100, elevated CRP, positive ANA (1:160), negative HLA-B27, normal ferritin, and negative S100 staining. Cytokine analysis showed elevated TNF, IL-6, MCP-1, IL-2, and IL-18. Targeted variant testing identified a UBA1 gene variant, c.123G>T p.(M41L), with low-level mosaicism (0.004%), and a heterozygous MEFV mutation. Although his ethnicity made Familial Mediterranean Fever unlikely, these findings raised the possibility of overlapping somatic and germline contributions to innate immune activation. He was treated empirically with immunosuppression for a presumed multisystem inflammatory disorder, resulting in resolution of symptoms and marked radiologic improvement. This case highlights the expanding spectrum of adult-onset autoinflammatory diseases that may present with pulmonary findings mimicking malignancy. The coexistence of low-level UBA1 mosaicism and MEFV mutation suggests a potential interaction between somatic and inherited variants in triggering inflammation. Similar to the recent discovery of VEXAS syndrome, this case may represent a novel subtype of autoinflammatory disease. Continued genomic and immunologic investigation is warranted, as timely recognition and immunosuppressive therapy can lead to dramatic recovery. This abstract is funded by: None

e23419 Background: Current risk assessment for cancer-associated thrombosis remain suboptimal in NSCLC, likely due to unaccounted tumor-specific biology. Although ALK and ROS1-positive NSCLC share closely related structure and elevated thrombotic risk, real-world data on thromboembolic outcomes remain limited. Methods: This multicenter retrospective study was conducted using TriNetX, a global federated health research network;14 of 113 healthcare organizations contributed to analysis. Adults (≥18 years) with NSCLC ROS1 or ALK from 2012-2025 were included. Index event was defined as the first documented NSCLC diagnosis. Outcomes included cumulative incidence, Kaplan–Meier survival analysis (KMS), and event recurrence for arterial thromboembolism (ATE), deep vein thrombosis (DVT), and pulmonary embolism (PE). Analyses were conducted pre and post-propensity score matching (PSM) adjusted for age and sex. Subgroup analyses evaluated outcomes at 1, 3, 6, and ≥12 months. Results: 3,310 NSCLC patients were identified (ALK n=3,155; ROS1 n=155). Mean age was 73 years, with 52.8% female and 46.2% male; 72.5% White, 12.7% Black, 9.5% Asian; South (49%), Northeast (29%). ALK NSCLC were older than those with ROS1 (mean 68.9 vs 64.6 years, p<0.0001), with similar sex distribution. ROS1 had higher proportion of White (85% vs 72%), while ALK included more Asian and Black. Median follow-up prior to matching was 482 days for ROS1 (post-PSM:482) and 546 days for ALK (post-PSM:601) Incidence proportions in ROS1 NSCLC were 12.3% for ATE, 9.7% for DVT, and 12.9% for PE (vs. ALK: 22.6% for ATE, 12.5% for DVT, 11.8% for PE) For ATE, prior to PSM, ROS1 NSCLC demonstrated a significantly lower risk compared with ALK (16.6% vs 25.0%), with an absolute risk difference of −8.4% (95% CI −14.7 to −2.2; p=0.02) and relative risk of 0.66 (95% CI 0.46–0.96). KMS showed longer ATE-free survival in ROS1 compared to ALK (48.2% vs 44.5%, p=0.01; HR 0.60, 95% CI 0.40–0.91, p=0.04). After PSM, overall ATE risk difference did not reach statistical significance, although ROS1 continued to demonstrate lower risk (16.6% vs 25.8%; risk difference −9.2%, p=0.06). Notably, in the subgroup analyses, this significant risk difference emerged ≥12 months, with improved late ATE-free survival in ROS1(91.1% vs 80.3%, p=0.01). For VTE and PE, no significant differences in risk, survival analyses or recurrence, were observed between ROS1 and ALK before or after PSM (DVT risk: 9.2% vs 9.7% pre-PSM; 9.2% vs 10.1% post-PSM; PE: 11.2% vs 9.9% pre-PSM; 11.2% vs 8.6% post-PSM; all p>0.05). Conclusions: Arterial thromboembolism differed by oncogenic subtype, with higher ATE risk in ALK compared with ROS1-positive NSCLC, particularly ≥12-months. In contrast, no significant difference in venous thromboembolism and pulmonary embolism were observed; further validation in prospective studies is warranted.

Abstract Rationale Chronic thromboembolic disease (CTED), which is the result of persistent pulmonary vascular obstruction despite 3 months of anticoagulation, can present with significant functional limitations and exercise intolerance despite normal resting hemodynamics. These patients may experience functional impairment due to exercise-induced pulmonary hypertension, impaired stroke volume augmentation with exercise, ventilatory inefficiency, and/or preload insufficiency. Such exercise-induced pathophysiological abnormalities can significantly impair quality of life and contribute to poor long-term outcomes. Although balloon pulmonary angioplasty (BPA) has shown benefit in patients with chronic thromboembolic pulmonary hypertension (CTEPH), its role in CTED patients with normal resting hemodynamics remains uncertain. This systematic review and meta-analysis evaluated the efficacy of BPA in this population. Methods A systematic search of PubMed, Cochrane, Embase, and Scopus was performed from inception through March 1, 2025. A total of 763 studies were screened, of which 42 full-text articles were assessed: six met the inclusion criteria (four retrospective, two prospective), comprising 98 patients. Results Across the included studies, baseline mean values were 20.81 +/- 3.62 mmHg for mean pulmonary arterial pressure (mPAP), 3.49 +/- 1.42 Wood units for pulmonary vascular resistance (PVR), and 405.72 +/- 108.40 m for the 6-minute walk distance (6MWD). Balloon Pulmonary Angioplasty (BPA) was consistently associated with significant improvements in hemodynamic and functional outcomes; BPA reduced mPAP by 3.40 mmHg and PVR by 0.90 WU, while increasing 6MWD by 31.90 m. These changes were also statistically robust across studies, with pooled standardized mean changes (SMC) of -0.88 for mPAP (95% CI, -1.10 to -0.67; P &lt; .05), -0.68 for PVR (95% CI, -0.87 to -0.49; P &lt; .05), and 0.29 for 6MWD (95% CI, 0.13 to 0.45; P &lt; .05). Study-level effect sizes for 6MWD ranged from 0.19 to 0.54 (Figure 1A). Functional improvements were further demonstrated by shifts in NYHA class distribution (Figure 1B). Conclusion BPA was associated with meaningful reductions in mPAP and PVR and significant improvements in functional capacity among patients with CTED. These results indicate that BPA could be an effective treatment for certain patients with CTED, though more research is necessary. This abstract is funded by: None

Abstract Rationale Chronic thromboembolic disease (CTED) is characterized by persistent pulmonary vascular obstruction due to unresolved thromboemboli despite at least three months of anticoagulation. Although resting hemodynamics often remain normal, affected patients frequently develop functional limitation due to exercise-induced pulmonary hypertension, ventilatory inefficiency, limited stroke volume augmentation, or preload insufficiency. Such exercise-induced pathophysiological dysregulation can significantly impair quality of life and contribute to poor long-term outcomes. Pulmonary endarterectomy (PEA) is an established treatment for Chronic Thromboembolic Pulmonary Hypertension (CTEPH), offering significant improvements in hemodynamics and survival. Its role in CTED, however, remains unclear. While CTED has traditionally been managed with anticoagulation and supportive therapy, emerging evidence suggests PEA may provide symptomatic and functional benefit in selected CTED patients. Given the ongoing uncertainty regarding the role of PEA in CTED, we performed a systematic review and meta-analysis to define its safety profile and clinical efficacy in this patient subset. Methods A systematic search of PubMed, Cochrane, Embase, Scopus, Web of Science, ClinicalTrials.gov, and Google Scholar was conducted from database inception to March 1, 2025. Of 2,244 records screened, 34 full-text articles were assessed, and seven met the inclusion criteria. Results Across the included studies, the pooled baseline mean values were 20.48 ± 3.03 mm Hg for mean pulmonary arterial pressure (mPAP), 2.83 ± 1.11 Wood units for pulmonary vascular resistance (PVR), and 397 ± 100.08 m for the 6-minute walk distance (6MWD). Pulmonary Endarterectomy (PEA) was consistently associated with significant improvements in hemodynamic and functional outcomes; PEA reduced mPAP by 3.58 mmHg (pooled Standardized Mean Change (SMC)=-1.03; 95% CI, -1.23 to -0.83; P &lt; .05), PVR by 0.86 Woods units (pooled SMC=-0.86; 95% CI, -1.05 to -0.67; P &lt; .05), while, conversely, increased 6MWD by 37.49 m (pooled SMC, 0.49; 95% CI, 0.32 to 0.67; P &lt; .05). Study-level effect sizes for 6MWD ranged from 0.21 to 1.47 (Figure 1A). This clinical improvement is further reflected in the enhancement of the NYHA functional class, as illustrated in Figure 1B. Conclusion PEA was associated with significant reductions in mPAP and PVR, as well as a considerable improvement in functional capacity in patients with CTED, with robust results across multiple tests for bias, influence, and sensitivity analyses. These findings support PEA as a viable therapeutic option for selected patients with CTED, although further research is warranted. This abstract is funded by: None

Abstract Background Sulfhemoglobinemia is a rare but potentially life-threatening dyshemoglobinemia resulting from the irreversible incorporation of sulfur into the heme moiety, producing hemoglobin species incapable of oxygen transport. Its clinical presentation often mimics methemoglobinemia, with cyanosis and oxygen saturation (SpO2) readings discordant from arterial partial pressure of oxygen (PaO2). Phenazopyridine, an over-the-counter urinary analgesic, has been implicated as a rare cause, in 3 previously documented cases. Prompt recognition is essential to avoid inappropriate therapy, particularly methylene blue, which can precipitate hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Case Presentation A 71-year-old man with Parkinson’s disease, Crohn’s disease, and chronic anemia presented with unexplained cyanosis and SpO2 readings in the 70-80% range, despite a normal PaO2 of 180 mmHg and absence of respiratory symptoms. He had self-initiated phenazopyridine for dysuria three days prior. CT angiography of the chest and echocardiography with bubble study were unremarkable. Attempts to quantify methemoglobin and carboxyhemoglobin were unsuccessful due to analyzer errors. Laboratory evaluation revealed acute anemia (hemoglobin 5.7 g/dL), indirect hyperbilirubinemia, and low haptoglobin consistent with hemolysis. He was managed supportively with high-flow oxygen, and transfusion of two packed red blood cell units. Although initial G6PD levels were normal, testing during hemolysis can yield false negatives. Given this and the risk of methylene blue-induced oxidative stress, conservative management with ascorbic acid was chosen. The patient’s SpO2 improved gradually, and he was discharged on hospital day three. Send-out tests later confirmed sulfhemoglobinemia (1.1%), elevated cytochrome b5 reductase activity, and normal methemoglobin. Discussion This case underscores the diagnostic and therapeutic challenge of differentiating sulfhemoglobinemia from methemoglobinemia. Both disorders produce functional hypoxia with SpO2-PaO2 dissociation, but sulfhemoglobin cannot revert to hemoglobin and requires erythrocyte turnover for resolution. While methylene blue is the standard therapy for methemoglobinemia, it is ineffective for sulfhemoglobinemia and contraindicated in G6PD deficiency. In our patient, supportive care and transfusion facilitated recovery. Using the Naranjo Adverse Drug Reaction Probability Scale, the causality score was 7, indicating a highly probable relationship between phenazopyridine exposure and sulfhemoglobinemia. A high index of suspicion for G6PD deficiency as well as dyshemoglobinemia with a multidisciplinary collaboration are essential for diagnosis and management of unexplained cyanosis. This abstract is funded by: None

Abstract Introduction Drug-induced pneumonitis is an important mimic of disseminated infection in immunocompromised hosts. Lenalidomide, an immunomodulatory agent widely used in multiple myeloma, has been associated with organizing and eosinophilic pneumonitis, and occasionally sarcoid-like granulomatous inflammation. The coexistence of acute fibrinous injury and granulomatous inflammation is exceptionally rare. We present a case of lenalidomide-associated acute fibrinous and granulomatous pneumonitis presenting with a miliary pattern following autologous stem cell transplant. Case Presentation A 44-year-old woman with kappa light-chain multiple myeloma, chronic kidney disease stage V, presented with 10 days of fever (to 105 °F), dry cough, hemoptysis, dyspnea and hypoxia requiring high flow oxygen. She had been on maintenance therapy with lenalidomide, daratumumab, and weekly dexamethasone after undergoing an autologous stem cell transplant for multiple myeloma, last administered one week before symptom onset.. CT chest (Figure 1-1) showed innumerable randomly distributed micronodules with ground-glass opacities and septal thickening, suggesting disseminated infection. Laboratory results revealed eosinophilia (950/µL), neutropenia, and profound hypogammaglobulinemia. Empiric piperacillin-tazobactam, doxycycline, and fluconazole were started for possible bacterial and/or fungal infection (history of positive Coccidioides IgM). Two bronchoscopies demonstrated multifocal hypervascular airway lesions. BAL differential showed 15 % eosinophils and &gt; 30 % lymphocytes; cultures, Fungitell, and comprehensive testing for bacterial, fungal, mycobacterial, viral, and parasitic pathogens were negative. Cryobiopsy revealed acute fibrinous and granulomatous pneumonitis with negative GMS and acid-fast stains. Following withdrawal of lenalidomide and daratumumab, the patient’s symptoms and CT findings improved without further antimicrobial therapy within the same hospitalization (Figure 1-2). She received an 8-week prednisone taper with inhaled pentamidine prophylaxis. Follow-up CT showed complete clinical and radiographic resolution (Figure 1-3), confirming a grade 3 drug-induced pneumonitis. A bronchoscopy will be repeated to assess the endobronchial vascular lesions. Discussion Lenalidomide related lung injury typically manifests as organizing or eosinophilic pneumonitis. The presence of both fibrinous and granulomatous inflammation suggests a mixed hypersensitivity and immune-complex reaction possibly potentiated by immune reconstitution after autologous transplant. The miliary pattern and BAL eosinophilia closely mimic disseminated fungal or mycobacterial infection. A Naranjo Adverse Drug Reaction Probability Scale score of 7 supported a highly probable causal relationship. Awareness of this pattern is essential, as prompt drug cessation and corticosteroid therapy are curative and prevent progression to fibrotic lung injury. This abstract is funded by: None

Background: Several special tests for detecting medial ulnar collateral ligament (MUCL) injuries of the elbow have been described, but data on the clinical utility of these tests are limited. Purpose: To determine the clinical utility of selected elbow special tests to detect MUCL injuries in an athletic population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 84 consecutive patients with sports-related elbow pain underwent a standardized clinical examination. Overall, 6 special tests (moving valgus stress test, static valgus stress test, modified valgus stress test, milking maneuver, pronation flexion resistance test, and temple/cheek press test) were performed. Sensitivity, specificity, accuracy, positive/negative predictive value, and positive/negative likelihood ratio (LR+ and LR–, respectively) were calculated for individual tests and combinations of tests to detect MUCL injuries. Higher values for the LR+ and lower values for the LR– represent stronger clinical utility. Results: For detecting MUCL injuries, the moving valgus stress test resulted in the highest sensitivity (98%) and accuracy (93%) with the lowest LR– (2%). The milking maneuver had the highest LR+ (5.1) with the second highest sensitivity (77%) and accuracy (79%). The pronation flexion resistance test and the temple/cheek press test had the lowest LR+ (1.5 and 1.8, respectively) and highest LR– (94% and 95%, respectively) in addition to the lowest sensitivity (16% and 9%, respectively) and accuracy (33% and 30%, respectively). No combination of tests resulted in increased clinical utility. Conclusion: The moving valgus stress test and milking maneuver demonstrated acceptable clinical utility in which the moving valgus stress test was better for ruling out MUCL injuries and the milking maneuver was better at ruling in MUCL injuries. There was no added value when combining the 2 tests together or with other maneuvers.

ABSTRACT Patients with chronic thromboembolic pulmonary disease (CTEPD) without resting pulmonary hypertension (PH) frequently experience dyspnea which is not explained by stationary assessment and therefore requires cardiopulmonary exercise testing for further diagnostic insight. Ventilatory inefficiency in CTEPD is commonly identified; however, consensus definitions are lacking. Upright iCPET and careful definition of ventilatory inefficiency (i.e., lack of reduction in VD/VT with exercise) may allow optimal characterization of patients with chronic thromboembolic disease and specifically helps correctly identify patients with preload insufficiency who may otherwise be misclassified or undiagnosed.

Abstract Introduction: Ewing sarcoma (EwS) is a FET::ETS family member-driven primary bone cancer demonstrating vast heterogeneity. Between a patient’s primary diagnosis and disease progression, tumor cell state adaptation, microenvironment changes, and the landscape of evolving therapeutic vulnerabilities remain poorly understood. To address these gaps, the Sean Karl Cohort was established in 2025 to conduct the largest single-cell transcriptomic analysis of retrospective paired tumor samples from patients with EwS. Here, we present data from the five analytic teams, and through shared SOPs now expand this cohort to Europe. Methods: Common sample processing SOPs were established to isolate cells from FFPE material from paired patient EwS samples. Single-cell (sc) RNAseq was generated using the GEM-X Flex Gene Expression protocol (10x Genomics). Alex’s Lemonade Stand Foundation (ALSF) Data Lab established a common data processing and integration pipeline with an EwS-specific cell annotation workflow to create a harmonized dataset for downstream analyses. Analytic teams were created to define tumor cell subpopulations and their therapeutic vulnerabilities and to characterize the tumor microenvironment. Data: We demonstrate the feasibility of generating high-quality scRNAseq profiles from retrospective FFPE-preserved EwS tumors. To date, 116 samples have yielded ∼800,000 cells. Integrated analysis reveals reproducible EwS tumor cell states shared across patients with regulatory network analyses nominating candidate therapeutic vulnerabilities. The scale of this international cohort enables saturation analysis for rare cell populations. Paired and longitudinal samples further allow correlation of emergent cell states with therapy resistance and metastatic progression. For example, immune-focused analyses show increases in T cell and macrophage populations in post-therapy samples. A novel, standardized EwS-specific cell annotation workflow has been developed to harmonize analyses and findings. These data will be openly shared with the community through the ALSF Single-cell Pediatric Cancer Atlas Portal. Conclusion: Large-scale international collaborative sample sharing, standardized processing pipelines, and harmonized EwS-specific annotations now enable deep single-cell analyses to characterize tumor heterogeneity in this rare pediatric and adolescent cancer. An in vivo expansion of the Sean Karl Cohort is underway to assess conservation of EwS tumor cell states and regulatory vulnerabilities identified in human tumors pre- and post-therapy in preclinical models, further supporting translation of these findings toward therapeutic strategies. Citation Format: Abbe Pannucci, Elina Mukherjee, Jessica D. Daley, Shireen Sita Ganapathi, Elissa Boguslawski, Lea Surrey, Lauren Gutstein, Patrick Azar, Emily Stockfisch, Azfar Neyaz, Ivy John, Jennifer Picarsic, Yutaro Tanaka, Byron Butaney, Riaz Gillani, Brian D. Crompton, Katherine A. Janeway, Jaclyln Taroni, Jessica Davis, Damon Reed, Adam Shlien, Theodore W. Laetsch, Rajen Mody, Clémence Henon, Thomas G. Grünewald, Elizabeth R. Lawlor, Filemon Dela Cruz, Patrick J. Grohar, Jovana Pavisic, Ally Hawkins, Anthony R. Cillo, Kelly M. Bailey. The Sean Karl Cohort: An international single-cell RNAseq study of paired patient Ewing sarcoma specimens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 643.