Background/Objectives: The loss of muscle mass is common in critically ill patients and is associated with poor prognosis, and efforts have been made to mitigate muscle loss through rehabilitation. This study aimed to evaluate changes in muscle mass in critically ill patients following rehabilitation. Methods: We enrolled 53 patients expected to stay in the ICU for more than 7 days, dividing them into rehabilitation (15 patients) and no rehabilitation groups (38 patients). Muscle mass was measured using ultrasound and bioelectrical impedance analysis (BIA). Results: Baseline characteristics and comorbidities showed no statistical differences between the two groups. Initial measurements of muscles showed no significant differences between the groups in rectus femoris thickness, total anterior thigh muscle thickness, cross-sectional area, echogenicity, or in-body skeletal muscle mass at baseline and 7 days. However, at 14 days, significant differences emerged. The rehabilitation group had greater rectus femoris thickness (1.42 cm vs. 0.81 cm, p = 0.007) and total anterior thigh muscle thickness (3.79 cm vs. 2.32 cm, p = 0.007) compared to the no rehabilitation group. Additionally, the rehabilitation group experienced a significantly smaller reduction in rectus femoris cross-sectional area (−4.6% vs. −22.8%, p = 0.021). Although survival rates were higher in the rehabilitation group (73.3% vs. 52.6%), this difference was not statistically significant (p = 0.096). Conclusions: Our findings suggest that rehabilitation in critically ill patients is associated with a slower rate of muscle loss, particularly in the cross-sectional area of the rectus femoris muscle, which may be beneficial for patient recovery.

Cancer‐associated dermatomyositis (CAD), a paraneoplastic syndrome characterized by dermatomyositis (DM), frequently presents in association with small cell lung cancer (SCLC). Although the advent of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, their efficacy and safety in patients with concurrent autoimmune diseases (AD) and malignancies remains uncertain. Several studies have suggested the safe administration of ICIs in patients with AD, indicating that successful cancer therapy can alleviate CAD symptoms. Conversely, other studies have raised concerns about the potential for ICIs to exacerbate AD flares or immune‐related adverse events (irAEs). A comparative analysis of two cases from our institution emphasizes the variability in ICI responses among SCLC patients with CAD. One patient, previously reported as a case study, exhibited significant clinical improvement in DM symptoms after ICI administration, whereas the other developed severe exfoliative skin changes and experienced an unfavorable prognosis. This variability emphasizes the need for careful patient selection and close monitoring during ICI treatment. We hypothesized that overweight or obese individuals and those with severe initial skin lesions and elevated lactate dehydrogenase levels are more susceptible to developing irAEs following ICI therapy. Therefore, caution is advised when considering immunotherapy in these patients.

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder frequently accompanied by multiple comorbidities, which can substantially influence prognosis and clinical management. Systemic inflammation and overlapping risk factors play significant roles in the pathogenesis of these comorbidities. Further, Preserved Ratio Impaired Spirometry (PRISm) has emerged as a condition indicating a high risk for COPD progression; nevertheless, the comorbidity burden of PRISm has not been adequately investigated. This review synthesizes major findings from clinically meaningful studies released in 2024, concentrating on cardiovascular diseases (CVD), pulmonary comorbidities, frailty, and obstructive sleep apnea (OSA) observed in both COPD and PRISm. CVD risk in COPD is modulated by disease phenotype, with severity and frequency of exacerbations being independent predictors of myocardial infarction and pulmonary embolism. Bronchiectasis may be present in as many as 69% of COPD patients and is linked to elevated rates of exacerbation and increased mortality. The newly proposed Radiological bronchiectasis, Obstruction, Symptoms, and Exposure (ROSE) criteria deliver an evidence-based approach to patient characterization in those with concurrent bronchiectasis and COPD. This approach has revealed that individuals fulfilling the ROSE criteria are at a higher risk for COPD exacerbations and exacerbation- related hospitalization. Additionally, recent evidence indicates a robust association between severe OSA and PRISm, with a notably higher prevalence in severe OSA cases (12.9%) versus mild/moderate OSA (6.2%). Both PRISm and COPD are associated with an accelerated progression of frailty, underlining the necessity for prompt recognition and multidisciplinary management of comorbidities. The collective evidence underscores the critical value of adopting a multidimensional assessment in COPD and PRISm, utilizing objective diagnostic criteria and the implementation of early therapeutic measures. It is recommended that future research emphasize longitudinal designs and precision-based interventions to optimize health outcomes within these groups.

Case Report Metachronous development of L858R and T790M EGFR mutations following ALK inhibitor therapy in stage IV lung adenocarcinoma: a case report So-Yun Kim, Jisoo Lee, Dongil Park, Jeong Eun Lee, Joo-Eun Lee, Hyun-Yi Kim, Da Hyun Kang, Chaeuk Chung

Background/Objectives: Pulmonary mass-like lesions may mimic malignancy, infection, or inflammatory disease, complicating diagnosis when radiologic, histopathologic, and microbiologic findings overlap. This case illustrates the importance of diagnostic reassessment when the clinical course and treatment response are not fully consistent with the initial diagnosis. Methods: A 69-year-old man with diabetes mellitus and mild emphysema presented with chronic cough, purulent sputum, and a recurrent left upper lobe mass. Computed tomography-guided biopsy revealed dense lymphoplasmacytic infiltration with eosinophils, fibrosis, and increased IgG4-positive plasma cells, leading to a presumptive diagnosis of IgG4-related lung disease. Limited improvement with steroid therapy and recurrent hemoptysis prompted multidisciplinary reassessment, including tissue metagenomic next-generation sequencing (mNGS). Results: Imaging findings were compatible with subacute invasive aspergillosis, although conventional fungal staining, culture, antigen testing, serologic studies, and bronchial washing analyses were negative. Tissue mNGS detected 348 low-abundance Aspergillus-derived reads, accounting for 0.03% of non-host reads. Following initiation of voriconazole, the lesion decreased from 47 mm to 32 mm within six weeks and regressed further thereafter. Symptoms resolved, and hemoptysis did not recur. Conclusions: This case highlights the importance of diagnostic reassessment when findings and treatment response do not fully support the initial diagnosis. Tissue mNGS may provide complementary evidence for probable subacute invasive aspergillosis when interpreted alongside radiologic findings, exclusion of alternative diagnoses, and treatment response.

Introduction: Home-based spirometry has emerged as a potential component of decentralized clinical trials (DCTs) in respiratory medicine, but its real-world feasibility in patients with chronic obstructive pulmonary disease (COPD) and other respiratory diseases remains insufficiently characterized. This study evaluated the feasibility of remote pulmonary function monitoring using a portable spirometer and mobile application in adults with COPD or other respiratory diseases. Methods: This exploratory single-arm study enrolled adults aged 19 years or older with COPD or other respiratory diseases. Participants were asked to perform home-based spirometry at six prespecified time points (Days 15, 29, 43, 57, 71, and 85). Feasibility was assessed using visit-level and participant-level adherence, spirometry quality grades, and patient-reported usability and satisfaction. Participants completing at least 5 of 6 scheduled measurements were classified as the high-adherence group; this cut-off was an operational, study-specific definition. Results: A total of 30 participants were enrolled (19 with chronic obstructive pulmonary disease, 5 with asthma, 2 with asthma–COPD overlap, and 4 with other respiratory conditions), and 23 completed the study. Visit-level completion rates declined over time, from 88.5% on Day 15 to 47.8% on Day 71 and 56.5% on Day 85. Nine participants completed all six measurements, while 13 completed at least five. Portable spirometry quality showed variability across visits, with both high-quality and low-quality measurements observed. Compared with the low-adherence group, the high-adherence group reported significantly higher scores for convenience, communication with the research team, overall satisfaction, willingness to participate in future telemedicine-based trials, device training adequacy, ease of device use, and application usability. Conclusions: Home-based spirometry may be a useful decentralized trial component in patients with COPD and other respiratory diseases; however, the decline in adherence over time and the variability in measurement quality indicate that substantial operational refinement is needed before broader implementation. Because no feasibility threshold was prespecified, no concurrent laboratory spirometry comparison was performed, and the study population was diagnostically heterogeneous, these findings are exploratory and address operational feasibility rather than measurement validity.