Background/Aims: This study investigated the clinical efficacy of low-dose mepolizumab (100 mg) in controlling severe eosinophilic asthma, aiming to induce eosinophilic granulomatosis with polyangiitis (EGPA) remission and reduce systemic steroid usage. Additionally, we constructed a basic frame for our longitudinal EGPA cohort by collecting serial blood samples before, during, and after mepolizumab treatment in EGPA patients. Methods: We conducted a 2-year prospective observational cohort study in patients with uncontrolled severe eosinophilic asthma and refractory EGPA who used systemic steroids (≥ 7.5 mg/day of prednisolone) or other immunosuppressant drugs for at least 6 months. All patients were treated with 100 mg of mepolizumab every 4 weeks for 1 year to control severe eosinophilic asthma and then were followed for an additional 1 year to monitor their disease course. We analyzed total systemic steroid use and EGPA remission/relapse during the study period. Results: Three EGPA patients were included in this study and completed 16 study visits over a 2-year period. After 1 year of treatment with mepolizumab (100 mg monthly), all 3 patients were able to reduce their maintenance dose of systemic steroids, with 2 patients completely discontinuing use. These 2 patients achieved EGPA remission during mepolizumab treatment, and their remission status remained stable for 1 year after they stopped receiving the medication. Conclusions Low-dose mepolizumab treatment demonstrated clinical efficacy in reducing the maintenance dose of systemic steroids required for severe refractory EGPA. While not all patients achieved EGPA remission with low-dose mepolizumab, some did, and their remission persisted even after treatment discontinuation.

Background/Aims: Gastric antral vascular ectasia (GAVE) is a rare but important cause of gastrointestinal (GI) bleeding. The clinical course of GAVE is not well-known, and recurrent bleeding from GAVE is a therapeutic challenge. Therefore, we investigated the clinical course of GAVE and identified the risk factors for bleeding from it. Methods: We retrospectively reviewed the records of patients diagnosed with GAVE using upper GI endoscopy at Asan Medical Center between January 2004 and December 2019 and evaluated the clinical course and risk factors for bleeding from GAVE. Results: Of the 348 patients (mean age, 62.3 ± 10.7 years; male, 62%), bleeding from GAVE occurred in 123 (35%) patients during follow-up (median, 17.3 months; interquartile range [IQR], 4.2–46.6). GI bleeding from GAVE was significantly associated with Child–Pugh class B or C liver cirrhosis (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.57–4.16), chronic kidney disease (CKD) (OR, 2.77; 95% CI, 1.52–5.07), use of antithrombotic agents (OR, 2.34; 95% CI, 1.13–4.82), and involvement of the duodenal bulb (OR, 3.21; 95% CI, 1.76–5.86). Rebleeding occurred in 39 of 123 patients (32%), in whom CKD (OR, 2.55; 95% CI, 1.12–5.81) was significantly associated with rebleeding. Endoscopic hemostasis was most commonly performed using argon plasma coagulation, and the median number of endoscopic hemostasis performed was 2 (IQR, 1–3). Conclusions A careful follow-up for bleeding is needed in GAVE patients with liver cirrhosis, CKD, use of antithrombotic agents, and duodenal bulb involvement.

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.

Background: Laser procedures are integral to dermatologic practice, yet safety measures- particularly regarding ocular protection and plume control- are poorly studied in real-world settings. Objective: To evaluate current practices in eye protection, infection control, and occupational risk awareness among Korean dermatologists performing laser treatments. Methods: A cross-sectional survey was conducted among board-certified dermatologists at the 2024 Korean Society for Dermatologic Laser Surgery meeting. The questionnaire covered demographics, laser frequency, use of goggles and masks, infection control strategies, ophthalmologic monitoring, and history of warts or cancer. Results: Seventy-nine respondents completed the survey. All reported using protective goggles, but only 26.6% and 22.8% did so for CO 2 and erbium-doped yttrium aluminium garnet lasers, respectively. Only 24.1% underwent regular eye exams, and 13.9% reported eye conditions after starting laser practice. While 89.9% used masks, 40.8% used dental masks, which are inadequate for plume protection. Suction devices were used by 94.9%, though performance specifications were unclear. Warts were reported by 46.8% of respondents; two reported cancer diagnoses after initiating laser work. Conclusion Despite high overall adherence to basic safety practices, critical gaps remain. Our findings highlight the need for standardized guidelines and long-term occupational health monitoring to ensure safe laser practice.

Background: Rosacea is a chronic inflammatory skin disorder characterized by erythema, papules, ocular symptoms, and heightened sensitivity. Patients with neurogenic symptoms such as burning or stinging remain particularly difficult to manage. Current guidelines often underrepresent energy-based devices (EBDs), pigmentary sequelae, psychosocial burden, and ocular comorbidities. Objective: To examine Korean dermatologists’ expert perspectives on rosacea management, focusing on skin sensitivity, neurogenic symptoms, pigmentary changes, psychosocial impact, ocular involvement, and EBD use. Methods: A web-based, 29-item survey was administered to 25 board-certified Korean dermatologists (May–June 2025). Quantitative and qualitative responses were analyzed. Results: Erythematotelangiectatic and papulopustular phenotypes with sensitivity skin predominated. EBDs (pulsed dye laser, intense pulsed light) were frequently used but limited by cost and sensitivity issues. Neurogenic symptoms were recognized but rarely treated with neuromodulators. Post-inflammatory hyperpigmentation was infrequent, yet monitoring was inconsistent.Psychosocial and ocular aspects were acknowledged but seldomly systematically addressed.Respondents expressed interest in emerging adjunctive treatments such as cold plasma, skin boosters, and holistic care approaches. Conclusion Korean dermatologists adopt individualized strategies for rosacea, yet practice gaps remain regarding neurogenic symptoms, pigmentary complications, and psychosocial and ocular comorbidities. Findings support the need for updated multidisciplinary, phenotype-driven guidelines aligned with real-world practice.

Background: Older patients aged ≥75 years are underrepresented in major statin trials, leaving the optimal statin intensity after acute ischemic stroke (AIS) undefined. We aimed to compare functional outcomes and short-term safety between high-intensity statin therapy (HIST) and moderate-intensity statin therapy (MIST) in patients aged ≥75 years with AIS or transient ischemic attack. Methods: Using a prospective stroke registry at a single tertiary center (2019–2022), we retrospectively analyzed 337 patients aged ≥75 years with AIS or transient ischemic attack who maintained statin therapy for 3 months (HIST n=117; MIST n=220). The primary outcome was a favorable 3-month functional outcome (modified Rankin Scale score 0–2). Secondary outcomes included stroke recurrence, adverse effects, and statin discontinuation. Multivariable logistic regression with pre-specified sensitivity analyses was performed. Results: Favorable outcomes at 3 months were more frequent with HIST (70.9% vs. 55.9%; p=0.010). After multivariable adjustment, HIST was independently associated with a favorable outcome (adjusted odds ratio [aOR]=2.03, 95% confidence interval [CI] 1.17–3.53), consistent across sensitivity analyses: per-protocol (aOR=3.48, 95% CI 1.97–6.17) and atrial fibrillation-adjusted (aOR=2.21, 95% CI 1.26–3.89). No significant differences were observed in statin discontinuation, stroke recurrence, or adverse effects. Conclusion In older patients with AIS, HIST was independently associated with better functional outcomes without evidence of increased harm, broadly consistent with current guideline recommendations for HIST when tolerated. Prospective studies are needed to confirm a causal relationship.

Background: We compared the immunoglobulin (IG) heavy chain (IGH) leader and FR1 primer sets to measure clone sizes and detect immunoglobulin heavy chain variable (IGHV) region somatic hypermutations (SHMs) in Korean patients with chronic lymphocytic leukemia (CLL). We also analyzed IGH and immunoglobulin kappa (IGK) to identify Korean-specific IGs in CLL. Methods: Next-generation sequencing (NGS)–based gene rearrangements and IGHV SHMs were assessed in 40 patients using IGH leader, IGH FR1, and IGK primers. Flow cytometry, karyotyping, interphase FISH, and NGS-based variant analyses were performed for 165 genes. Results: Clonal IGH and IGK rearrangements were detected in 100.0% and 97.5% of patients, respectively. Clonal size was generally smaller per NGS than per flow cytometry, particularly when using the IGH leader (median: 52.5%) versus the IGH FR1 primer set (73.2%). IGHV SHMs occurred in approximately 70% of patients; 10% showed primer set discrepancies. The incidence of IGHV SHMs was low in patients at high risk (i.e., with TP53 abnormalities; complex karyotypes; and ATM, NOTCH1, SF3B1, or BIRC3 variants). IGHV3 was the most common IGHV (58.3%), and IGHV4-34 was most frequently identified (14.6%). IGHV1 and IGHV1-69 usage differed significantly between Koreans and westerners. IGHJ4 was the most common IGHJ (56.3%). A single IGKV–IGKJ gene rearrangement was most frequently observed (18.9%), whereas intron-KDE was the most common rearrangement (30.6%). Conclusions NGS may underestimate CLL clonal size, particularly when using the IGH leader primer set. IGHV SHMs were inversely associated with negative prognostic factors.Our data suggest ethnic differences in CLL pathogenesis.

Background: Recent advancements in large language models (LLMs) have accelerated their integration into clinical domains, including laboratory medicine. The performance of LLMs in answering board-level laboratory medicine questions has not been comprehensively evaluated. Given the importance of diagnostic accuracy in this field, rigorous and objective evaluations of LLM capabilities are essential. Methods: We assessed 12 LLMs from OpenAI, Anthropic, and Google using 320 Korean Residency Examination questions (2021–2024) spanning six laboratory medicine subspecialties. Standardized prompts were provided via their application programming interfaces under deterministic settings (temperature = 0). Questions were administered thrice to assess response reproducibility. Outputs were compared with validated answers and analyzed for accuracy, reasoning quality, and error typology. Results: Google’s Gemini 2.0 Pro achieved the highest accuracy (80.0%), followed by OpenAI’s GPT-4.5 (77.2%) and Anthropic’s Claude 3.7 Sonnet (74.1%). Accuracy decreased as the difficulty of questions increased (78.0% for easy vs. 45.1% for challenging). Subspecialty performance varied. Al models underperformed on questions on transfusion medicine (mean accuracy: 38.8%), primarily because of limitations in domain-specific and regional knowledge representations. Incorrect answers primarily resulted from reasoning errors. Reproducibility exceeded 95% for most models; however, some residual non-determinism appeared even with greedy decoding (temperature = 0). Conclusions LLMs demonstrated substantial potential for integration into laboratory medicine, particularly in clinical chemistry and immunology. Performance inconsistencies (particularly for high-difficulty questions) and knowledge gaps (notably for transfusion medicine) highlight the necessity for further development—potentially including domain-specific fine-tuning and retrieval-augmented generation integration—and robust expert oversight before clinical application.

Purpose: We aimed to compare the final adult height (FAH) of male patients with central precocious puberty (CPP) after treatment with a gonadotropin-releasing hormone agonist (GnRHa). Specifically, we compared FAH with the target height (TH) and the predicted adult height (PAH) before and after GnRHa treatment to quantify height gain and identify predictive factors. Methods: We retrospectively reviewed the medical records of 92 male patients with CPP and known FAH after GnRHa treatment at the Department of Pediatrics of Severance Children’s Hospital between January 2000 and June 2024. Results: The mean duration of GnRHa treatment was 2.7±1.3 years. A significant 1.1±0.9 years narrowing was observed in the difference between bone age (BA) and chronological age (CA) during treatment (P<0.001). TH was 172.4±3.4 cm. FAH was 173.6±6.4 cm. FAH was greater than TH by 1.2±5.9 cm (P=0.047). PAH before and after treatment was 179.9±8.1 and 181.2±7.4 cm, respectively. PAH was increased by 1.3±4.9 cm (P=0.012) after treatment. As the PAH standard deviation score (SDS) before GnRHa treatment increased, FAH tended to exceed TH. In contrast, higher testosterone levels before treatment are associated with FAH falling below TH. A longer duration of treatment and taller TH are associated with an FAH SDS greater than height SDS before treatment. Conversely, a greater weight SDS, BA–CA difference, and testis size before treatment are associated with FAH SDS being less than height SDS before GnRHa treatment. Conclusion GnRHa treatment improved FAH and inhibited bone maturation in male patients with CPP.