Background: This study was performed to establish a rabbit model for esophageal surgery in the treatment of cervical esophageal diseases. The necessary steps for postoperative treatment and esophageal examination were detailed. Methods: This study aimed to confirm the feasibility of the surgical procedure in rabbits and develop a postoperative management protocol. Six New Zealand White rabbits underwent esophagectomy and end-to-end anastomosis of the cervical esophagus under general anesthesia. Postoperatively, the rabbits were fed a specially formulated therapeutic liquid diet for 3 to 7 days. Recovery was monitored for 8 weeks, after which the rabbits were euthanized. Esophagography and endoscopy were conducted during the first postoperative week to assess healing. Results: Of the six rabbits that underwent surgery, two died from nonsurgical complications within 7 days after the operation. Of the remaining rabbits, two were diagnosed with esophageal stricture via esophagography and underwent endoscopy after the first postoperative week. The final two rabbits completed the 8-week postoperative period without complications. Conclusions Esophageal surgery and postoperative treatment in rabbits require careful attention. We anticipate that this study will provide valuable and practical information for researchers conducting esophageal studies using rabbits.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Background and Objectives: Studies investigating the correlation between papillary thyroid carcinoma (PTC) tumor size and the prevalence of the B-type Raf kinase (BRAF) mutation have yielded conflicting results. Therefore, we evaluated the prevalence of BRAF mutation according to tumor size in a large cohort of PTC patients to clarify this association. Materials and Methods: We retrospectively analyzed 6,438 patients with surgically diagnosed classic PTC between January 2009 and December 2017 at Samsung Medical Center, Seoul, Republic of Korea.During the study period, BRAF mutation testing was attempted on all fine-needle aspiration specimens, except for a small number of inadequate specimens. All other histologic subtypes were excluded. The prevalence of BRAF mutation was assessed based on tumor size, and further analyzed by age group and sex according to tumor size. Results: The overall prevalence of BRAF mutation was 79.2%. When PTCs ≤1 cm were excluded, the prevalence was 77.2%. The prevalence significantly decreased with increasing tumor size (p for trend ＜0.001). It was significantly higher in men than in women (p=0.013), but did not differ by age. The inverse correlation between tumor size and prevalence was prominent in patients aged 20-49 years but was less distinct in those aged 50 years and older. Conclusion In this large cohort of patients with PTC, the prevalence of BRAF mutation significantly decreased with increasing tumor size. These findings suggest that BRAF mutation is enriched in smaller surgically treated classic PTCs and may provide a hypothesis-generating clue regarding its role in early PTC development, although selection bias cannot be excluded.

Hepatic angiomyolipoma is a rare benign tumor that often mimics hepatocellular carcinoma on imaging. Here, we report a rare case of hepatic angiomyolipoma with extensive hemorrhagic degeneration, resulting in a large hemorrhagic component that mimicked a complicated cystic neoplasm. A 43-year-old woman presented with mild abdominal distension, and imaging revealed a 16-cm multiloculated cystic mass in the left hepatic lobe. Computed tomography revealed a thick, enhancing wall and septa with hyperattenuating internal fluid. On gadoxetic acid-enhanced magnetic resonance imaging, arterial enhancement was observed along the thick wall, and a subtle opposedphase signal drop indicated a small fat component that was initially missed. Laparoscopic left lobectomy was performed under suspicion of a malignant cystic neoplasm. Histopathological examination revealed an angiomyolipoma composed of thick-walled vessels, spindle-shaped muscle bundles, and scant adipocytes, with human melanoma black 45 positivity and absence of an epithelial lining, consistent with hemorrhagic degeneration. This case highlights how hemorrhagic degeneration can pose a significant diagnostic challenge by masking the typical features of hepatic angiomyolipoma, leading to diagnostic confusion with complicated cystic tumors.

Background: Dual energy X-ray absorptiometry (DXA) measurements vary among instruments from different manufacturers. This study aimed to assess the correlation between bone mineral density (BMD) and body composition measured by the GE Lunar Prodigy and Hologic Horizon W DXA systems and to develop conversion equations. Methods: A total of 120 healthy volunteers (59 males, 61 females) aged 20 to 70 years were scanned on both DXA systems on the same day. BMD was measured at the lumbar spine (L1-L4) and bilateral femurs. Body composition parameters were measured for the whole body and regional sites. Bland-Altman analysis, Pearson correlation, and concordance correlation coefficient (CCC) were used to assess agreement. Linear regression was performed to derive conversion equations. Results: The Hologic system measured BMD values 14% to 20% lower at the lumbar spine and 8% to 17% lower at femoral sites compared to the GE Lunar system (all P<0.0001). Lean mass values were 4% to 10% lower on the Hologic system. Very strong correlations were observed for both BMD (r=0.944-0.980) and lean mass (r=0.963-0.984). Cross-calibration equations were developed for all measurement sites. Conclusions Despite significant systematic differences, there was very high correlation between the two DXA systems. The conversion equations can facilitate comparison of measurements between these systems in clinical practice and research.

Purpose: Based on the KEYNOTE-522 study, neoadjuvant pembrolizumab plus chemotherapy has become the standard treatment for early-stage triple-negative breast cancer (TNBC).This study evaluated the real-world efficacy, safety, and predictors of pathologic complete response (pCR) in Korean patients. Methods: We conducted a retrospective cohort study of 174 patients with early-stage TNBC who received the KEYNOTE-522 regimen (neoadjuvant pembrolizumab plus paclitaxel and carboplatin, followed by doxorubicin and cyclophosphamide) at a tertiary cancer center between August 2022 and July 2024. We assessed the primary endpoints, including pCR rate and event-free survival (EFS). We performed univariable and multivariable logistic regression analyses to identify independent predictors of pCR. Results: The median patient age was 50 years (range, 24–74 years). The clinical stages were II and III in 79.3% and 20.1% of patients, respectively, and 10.9% had clinical N3 disease. The overall pCR rate was 62.1%, and the N3 subgroup had a pCR rate of 47.4%. On multivariable analysis, high baseline Ki-67 expression (≥ median, 75%) was significantly associated with pCR (odds ratio, 2.84; 95% confidence interval, 1.45 to 5.66; p = 0.002). At a median followup of 18.4 months, the 12-month EFS rate was 97.4%, with significantly superior outcomes observed in patients who achieved pCR compared with those who did not achieve pCR (100% vs. 93.1%, p = 0.007). The treatment completion rate was 92.0%, and immune-related adverse events occurred in 13.8% of patients. Conclusion In this real-world analysis of one of the largest Asian cohorts of patients with earlystage TNBC treated with neoadjuvant pembrolizumab, the KEYNOTE-522 regimen demonstrated substantial efficacy and manageable toxicity, consistent with the original trial findings.

Purpose: This study compared the efficacy of different irrigation methods for the removal of Ca(OH)2 paste from the root canal. Materials and Methods: The root canals of 75 human mandibular premolars with standardized 15-mm canal lengths were prepared using nickel-titanium rotary files. After drying, the canals were filled with Ca(OH)2 paste. The teeth were divided into five groups: Control group (Group C), conventional irrigation; Group EA, sonic activation (EndoActivator); Groups EQA and EQB, sonic activation (EQ-S with metal tips A and B, respectively); and Group EU, ultrasonic activation (EndoUltra).The Ca(OH)2 paste volume before and after irrigation was measured using micro-computed tomography (CT) images. One specimen from each group was bisected along the long axis, and the canal walls were evaluated at 100× magnification using a scanning electron microscope. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. Results: Overall, Ca(OH)2 paste removal was higher in Group EQA than in Group C. In the coronal third, removal rate was higher in Group EQA than in Group C. In the middle third, Groups EQB and EU outperformed Group C. Removal from the apical third was higher in Group EQA than in Group C. All groups showed greater removal from the coronal and middle thirds than from the apical third. Conclusion Sonic and ultrasonic irrigation methods demonstrated higher efficacy than conventional irrigation method for the removal of Ca(OH)2 paste from the root canal. All groups demonstrated better effectiveness in removal from the coronal and middle thirds than from the apical third.

Vaccines are highly effective, but rare or delayed adverse events following immunization (AEFIs) require post-licensure surveillance beyond clinical trials. Korea lacks a comprehensive, active, database-based framework, yet key assets exist: nationwide claims databases (National Health Insurance Service/Health Insurance Review and Assessment Service), the national immunization registry (Korea Disease Control and Prevention Agency’s Immunization Registry Information System) for National Immunization Program (NIP) and non-NIP vaccines, and increasingly standardized hospital electronic health records.We propose a federated, code to data architecture with data linkages between these data.Implementation should adopt a common data model (CDM), standardized case definitions, latency accounting, and transparent public reporting under strong privacy governance. Major challenges include multi step administrative approvals for data linkage, incomplete capture of adult non-NIP vaccinations, heterogeneous hospital data structures, and strict data protection constraints. Strategic priorities are to streamline statutory and administrative processes for public health use, mandate or enable claims-based capture of adult vaccinations, enhance CDM based interoperability, and develop secure hubs for aggregated outputs. With these measures, Korea will be well positioned to establish a scalable active surveillance system capable of detecting rare AEFIs, supporting transparent and evidence-based communication, and ensuring equitable injury compensation grounded in domestic data.

Objectives: Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research. Methods: Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes. Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes. Results: Data from 5460 ESD cases from 5250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days. Conclusions This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.