Hypersensitivity reactions (HSRs) to iodinated contrast media (ICM) can range from mild cutaneous symptoms to life-threatening anaphylaxis. In patients with a history of ICM hypersensitivity, avoidance of the culprit agent is generally recommended. This case report describes a successful desensitization in a 56-year-old man with recurrent HSRs to multiple agents including ioversol, iohexol, iobitridol, and iopamidol. Intradermal testing was performed to identify potentially safe alternatives; however, all tested agents, including iohexol, ioversol, iobitridol, iopamidol, iodixanol, iomeprol, and iopromide, yielded positive results. Given the clinical necessity of transcatheter arterial chemoembolization, a 13-step rapid desensitization protocol with iodixanol was implemented. The procedure was completed without any breakthrough reactions. This case highlights desensitization as a feasible and effective strategy for patients with hypersensitivity to multiple ICM agents.

Idiopathic inflammatory myopathies (IIMs) are heterogeneous immune-mediated muscle disorders with variable extramuscular manifestations and outcomes. Myositis-specific auto-antibodies (MSAs) have transformed the IIM field by enabling a serology-informed taxonomy based on distinct clinical phenotypes, prognostic trajectories, and therapeutic responses. Anti-Jo-1 and other antisynthetase antibodies characterize interstitial lung disease (ILD)-prone forms of disease; anti-MDA5 identifies patients at risk of rapidly progressive ILD and early mortality; anti-TIF1-γ and anti-NXP2 are indicative of cancer-associated myositis; anti-SRP and anti-HMGCR delineate necrotizing myopathies; and anti-cN1A supports the diagnosis of inclusion-body myositis. Beyond diagnosis, MSA profiles provide prognostic information, including about survival, relapse risk, and organ-specific complications, and they are increasingly being used to guide treatment decisions and predict biologic responsiveness. This review summarizes the diagnostic, prognostic, and therapeutic implications of MSAs across the IIM spectrum and highlight their growing importance in clinical practice for risk stratification and patient management.

Rectal cancer, which accounts for approximately 40% of colorectal cancers, remains a major clinical concern. Recent advances in diagnostic imaging, surgical techniques, radiotherapy, and systemic treatment have steadily improved rectal cancer outcomes. Considering this, the Korean Rectal Cancer Multidisciplinary (KRCM) Committee has aimed to provide clinicians and policymakers with up-to-date, evidence-based clinical practice guidelines to support optimal decision-making, reflecting current evidence, the Korean healthcare context, and patient values and preferences. The Clinical Practice Guidelines for Rectal Cancer version 2.0 were developed through multidisciplinary collaboration with related academic societies, building upon and updating the KRCM Clinical Practice Guidelines version 1.0 (titled “Multidisciplinary guidelines for the management of rectal cancer”). These consensus guidelines of the KRCM were established based on a comprehensive literature review, evidence synthesis, with recommendation development guided by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology, and consideration of applicability in real-world clinical practice under the national health insurance system. Each recommendation has been presented with its strength and level of evidence.

Sarcopenia is a major geriatric syndrome characterized by progressive loss of muscle mass and strength, resulting in disability and mortality. This narrative review synthesizes international consensus recommendations and Korean evidence to guide context-specific sarcopenia management strategies. PubMed, Embase, Cochrane Library, and KoreaMed (January 2000–November 2025) were searched, focusing on randomized trials, meta-analyses, systematic reviews, clinical practice guidelines, and large observational studies. Global diagnostic frameworks have evolved from muscle mass-based definitions toward multidimensional models that incorporate muscle strength and physical performance. Exercise and nutrition remain the mainstay treatments, with resistance-based training and adequate protein intake. Currently, pharmacologic options with proven clinical benefit are limited. In Korea, growing evidence supports the effectiveness of community-based sarcopenia interventions, underscoring the need for standardized, integrated delivery models that bridge the fragmented healthcare system and enable sustainable implementation.

Background: Mycoplasma pneumoniae is a major cause of community-acquired pneumonia (CAP) in children, with a rising incidence of macrolide resistance. Early diagnosis is crucial for reducing the disease burden; however, current diagnostic tools have limitations.We evaluated the diagnostic accuracy of serological assays and their performance based on symptom onset in children with CAP. Methods: From September 2023 to September 2024, we prospectively enrolled children with CAP, classified as M. pneumoniae pneumonia (MPP) or non-MPP, from 16 hospitals in Korea. Serological testing included chemiluminescence immunoassay (CLIA) and ELISA for detecting IgM and IgG, along with particle agglutination (PA) for total antibody measurements. Serological responses were analyzed at different times after symptom onset (0–4, 5–9, and 10–21 days). Results: Among 472 children with CAP (362 MPP, 110 non-MPP), 138 (29.2%) underwent PA testing, and 334 (70.8%) underwent IgM testing. PA at a 1:640 cutoff showed 48.0% sensitivity and 100% specificity. CLIA and ELISA showed comparable sensitivities (69.1% vs. 69.2%) and specificities (76.9% vs. 66.7%) for IgM testing. Seropositivity increased significantly with time since symptom onset (P for trend < 0.001), reaching 97.9% for IgM, 62.5% for IgG, and 94.7% for PA at 10–21 days. Conclusions The time post-symptom onset significantly influenced the diagnostic utility of serological tests for pediatric MPP, which showed limited value during the early stage of illness. These findings emphasize the importance of symptom onset-based interpretation of serological test results and their utility in complementing PCR when optimizing MPP diagnosis in children.

Purpose: This study aimed to estimate the mortality rate in adult intensive care units (ICUs) using the Charlson comorbidity index (CCI)-adjusted Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) III models, and to identify factors influencing mortality. Methods: This retrospective cohort study included adult patients admitted to the ICU at a tertiary hospital between June 1 and August 31, 2022. Among the 1,098 screened patients, those younger than 18 years, those discharged within 48 hours, and those with missing medical records were excluded. In total, 482 patients were analyzed using the chi-square test, independent t-test, and multivariate logistic regression. Model performance was evaluated using the c-statistic and the Hosmer-Lemeshow goodness-of-fit test. Results: The predictive accuracy of the mortality models was shown by c-statistic values of 0.817 for APACHE II, 0.857 for SAPS III, 0.697 for CCI, and 0.834 for CCI-adjusted APACHE II (0.834). Mechanical ventilation, cardiopulmonary cerebral resuscitation, continuous renal replacement therapy, and the presence of leukemia or lymphoma were significant predictors of mortality in adult ICU patients. Among the evaluated models, SAPS III and CCI-adjusted APACHE II demonstrated the highest predictive power. Conclusion The findings indicate that incorporating comorbidity indices such as the CCI with acute physiological parameters improves the accuracy of mortality prediction in ICU patients. Understanding mortality prediction models is essential for nurses to provide individualized, evidence-based, and high-quality care in adult ICUs.

Background/Aims: Patients with postural tachycardia syndrome (POTS) commonly experience gastrointestinal (GI) symptoms. We aim to assess the feasibility and preliminary efficacy data for DA-9701, a prokinetic agent targeting 5-hy-droxytryptamine 1A, 5-hydroxytryptamine 4, and dopamine D 2 receptors, in patients with POTS. Methods: In a randomized, double-blind, placebo-controlled, single-center crossover trial, patients with POTS were given either 30 mg of DA-9701 or a placebo 3 times daily for eight weeks in a 1:1 ratio. After a 4-week washout, patients received the alternate treatment for another 8 weeks. The primary endpoint focused on assessing the change in GI symptoms (total Nepean Dyspepsia Index-Korean version [NDI-K] symptom score) from baseline over the 8 week-treatment period. Endpoints were assessed in all enrolled and randomized patients (intention-to-treat), and in those who completed the trial (per-protocol analysis). Results: Between January 2022 and August 2023, 24 patients were randomized (n = 12 per group), with 3 discontinuing after randomization. DA-9701 did not significantly improve primary endpoints for total NDI-K symptom scores in either the intention-to-treat (least-squares means, –13.9 vs. –9.5, P = 0.326) or per-protocol analyses (–17.2 vs –12.0, P = 0.242).Notably, a trend toward improvement in specific GI symptoms, such as upper abdominal pain, was observed in both intention-to-treat (–0.6 vs 0.7; P = 0.066) and per-protocol analyses (–0.9 vs 0.6; P = 0.045). No serious adverse events were observed. Conclusion DA-9701 did not improve GI symptoms in this crossover trial; however, its potential effect on specific GI symptoms merits further investigation.

This study aimed to determine the prevalence of human epidermal growth factor receptor 2 (HER2)–ultralow breast cancer among cases initially classified as HER2 immunohistochemistry (IHC) 0 and assess interobserver variability in interpreting low-level HER2 expression. Methods: In this multicenter retrospective study, all invasive breast cancer cases diagnosed between January and December 2022 across 10 Korean institutions were retrieved. Institutional pathologists reexamined HER2 IHC slides originally reported as IHC 0 according to the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines and reclassified them as HER2-null (0), HER2-ultralow (0+), or HER2-low (1+). Slides from 10% of HER2-null and HER2-ultralow cases were digitized for central review and independently assessed by two pathologists, with discrepancies resolved by consensus. Results: Among 8,026 cases, 2,836 cases (35.5%) were initially reported as IHC 0. Upon re-review, 1,673 (59.0%), 1,139 (40.2%), and 24 (0.8%) cases were reclassified as HER2-null, HER2-ultralow, and HER2-low, respectively. The prevalence of HER2-ultralow breast cancer varied considerably across institutions (23.7%–78.1%). Central review of 268 digitized cases showed concordance in 193 cases (72.0%). Among the 75 discordant cases, 54 tumors (72.0%) were upgraded from HER2-null to HER2-ultralow, and 18 (24.0%) tumors were upgraded from HER2-ultralow to HER2-low. Furthermore, two tumors (2.7%) were downgraded from HER2-ultralow to HER2-null. Conclusions: Approximately 40% of cases initially categorized as IHC 0 were reclassified as HER2-ultralow. The substantial inter-institutional variability observed in interpreting low-level HER2 expression highlights the need for standardized training and quality assurance to ensure accurate identification of patients eligible for HER2-targeted antibody–drug conjugates.

Objective: To evaluate the performance of supplemental automated breast ultrasound (ABUS) added to mammography-based breast cancer screening for women with nondense breasts. Materials and Methods: A retrospective search of radiology databases at two tertiary institutions identified asymptomatic women with nondense breasts who underwent breast cancer screening using both digital mammography (DM) and supplemental ABUS between January 2020 and December 2023. We excluded women without sufficient follow-up data or those without an established final diagnosis, including histopathologic results. The performance measures of DM alone and ABUS combined with DM (ABUS plus DM) were compared. The primary outcome was the cancer detection rate (CDR), and the secondary outcomes were sensitivity and specificity. Subgroup analyses were performed for women with scattered fibroglandular density and almost entirely fatty breasts. Results: A total of 2,904 pairs of screening examinations were performed in 1,683 women (59 ± 10 years), detecting 26 cancers. In comparison with DM alone, ABUS plus DM showed higher CDR (9.0 vs. 7.9 per 1,000 examinations, P < 0.001), higher sensitivity (100% [26/26] vs. 88.5% [23/26], P < 0.001), and lower specificity (95.0% [2,735/2,878] vs. 97.9% [2,817/2,878], P < 0.001). In women with scattered fibroglandular density, ABUS increased the CDR from 7.4 to 8.5 per 1,000 examinations and improved the sensitivity from 87.0% [20/23] to 100% [23/23] (P < 0.001). In women with almost entirely fatty breasts, ABUS plus DM showed the same CDR (16.4 per 1,000 examinations) and sensitivity (100% [3/3]) as DM alone. Three cancers (11.5% [3/26]), all of which were stage T1N0, were detected only by supplemental ABUS. Conclusion Supplemental ABUS improved cancer detection and sensitivity in women with nondense breasts, with the benefits primarily observed in those with scattered fibroglandular density.