Background: Enzyme immunoassays (EIAs), which detect glutamate dehydrogenase (GDH) and toxin A/B, are widely used to screen for Clostridioides difficile infection (CDI); however, their sensitivity is lower than that of molecular assays. This study aimed to evaluate the performance of two EIAs, C. Diff Quik Chek Complete (QCC) and RIDASCREEN (RIDA), and investigate the cycle threshold (Ct) values from two real-time polymerase chain reaction (PCR) assays (Allplex GI–Bacteria(I) and Xpert C. difficile) in EIA-discordant samples. Methods: A total of 180 clinical stool samples were tested using QCC, RIDA, and Allplex GI– Bacteria(I) PCR assays. The Xpert C. difficile assay was used to analyze discordant results. Results: QCC and RIDA showed high sensitivities for GDH detection, 100.0% and 94.4%, respectively. QCC was significantly more sensitive than RIDA for toxin detection (51.4% vs. 28.6%, p = 0.007). In 25 EIA-discordant, Xpert positive samples, the Ct values of the toxin B gene ranged from 31.5 to 44.8 (mean, 38.1) for Allplex PCR and from 23.7 to 36.3 (mean, 30.4) for Xpert PCR. The Ct values of the two PCR assays were not significantly correlated (r = 0.201, p = 0.324). Conclusion QCC is a suitable initial immunological test for diagnosing CDI. The lack of correlation in the Ct values between the two real-time PCR assays suggests that assay-specific validation is necessary for cutoff level interpretation.

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: 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: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs).Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in E.coli. CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant E. coli strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of E. coli bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance. Methods: We collected all non-duplicated isolates of E. coli and related clinical information from patients with BSIs at eight sentinel hospitals in the Korean Global Antimicrobial Resistance Surveillance System (Kor-GLASS) collection network during 2017–2021. Duplicate isolates were removed to ensure representativeness of the data. Antimicrobial susceptibility was tested using disk diffusion tests, and multilocus sequence typing and betalactamase genotyping were performed. Results: Among 9,232 E. coli blood isolates, resistance rates to cefotaxime and ceftazidime were 36.4% and 11.4%, respectively. Among the clinical factors, age > 65 yrs (adjusted odds ratio [aOR], 1.36), hospital-origin infection (aOR, 2.55), and admission type (intensive care unit [ICU] vs. general ward; aOR, 1.34) were significant cefotaxime resistance risk factors. ST131 was the most prevalent among cefotaxime-resistant E. coli (64.8%, 2,180/3,363), followed by ST1193 (5.3%, N = 177), and ST69 (5.1%, N = 170).ST131, ST648, ST405, and ST410 cefotaxime-resistant E. coli isolates frequently harbored blaCTX-M-15, whereas ST1193 and ST68 showed a high proportion of blaCTX-M-27 carriers, and most ST457 and ST5150 isolates carried blaCTX-M-55. Conclusions Continuous monitoring of ESBL-producing E. coli is required to prevent further dissemination, guide empirical therapy, inform infection control policies, and ensure early detection of multidrug-resistant clones with the potential for widespread transmission.

Some viral infections display distinct seasonal patterns influenced by factors such as climate, human behavior, and viral characteristics. In this review, we investigated the seasonality of 15 viral infections in Korea. We analyzed viruses for which national surveillance data are available from the Korea Disease Control and Prevention Agency, including influenza virus, respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus, metapneumovirus, human bocavirus, seasonal coronaviruses, enterovirus, adenovirus, norovirus, rotavirus, Japanese encephalitis virus, Hantaan virus, varicella–zoster virus, and mumps virus. In temperate climates, such as that in Korea, winter peaks are commonly observed for influenza, RSV, and norovirus infections, whereas enteroviruses are more prevalent in summer and early autumn. Parainfluenza viruses exhibit type-specific seasonality (circulating in warmer months from spring to autumn). During the coronavirus disease 2019 pandemic (2020– 2021), the incidence of most respiratory and gastrointestinal viral infections analyzed in this study declined substantially owing to non-pharmaceutical interventions, such as social distancing and mask-wearing. After the preventive measures were relaxed, many viruses initially exhibited delayed or atypical seasonal peaks. However, by 2024, the seasonality of most, but not all, viral infections had largely returned to their pre-pandemic patterns. We also reviewed factors influencing viral seasonality, including climatic conditions, vector activity, human behavior, immunity, and viral genetic variation. These findings highlight the dynamic nature of viral seasonality and reinforce the importance of timely surveillance and flexible public health responses tailored to each country’s epidemiological landscape.

Objective: Although most gallbladder polyps are benign, some neoplastic polyps may be malignant or may serve as precursors to malignancy. Distinguishing neoplastic and non-neoplastic polyps using imaging examinations remains a major challenge.This meta-analysis aimed to identify the ultrasound (US) features that are significantly associated with neoplastic polyps. Materials and Methods: The MEDLINE, EMBASE, Cochrane, and KoreaMed databases were searched for articles published up to August 31, 2025. Bivariate random-effects models were used to calculate the meta-analytic pooled diagnostic odds ratios (DORs), sensitivities, and specificities, along with their 95% confidence intervals (CIs), for each US imaging feature in the diagnosis of neoplastic polyps. Results: Thirty studies evaluating 8,953 patients, including 1,216 (13.6%) patients with neoplastic polyps, were included.Among the nine evaluated US imaging features, namely, size ≥10 mm, sessile morphology, single polyp, coexisting gallstones, hypoechogenicity, heterogeneous echogenicity, gallbladder wall thickening (GBWT), absence of hyperechoic spot, and vascularity, eight were significantly associated with neoplastic polyps: size ≥10 mm (DOR: 6.23 [95% CI: 1.86– 20.90]), sessile morphology (DOR: 3.54 [1.93–5.97]), single polyp (DOR: 2.21 [1.76–2.74]), coexisting gallstones (DOR:1.86 [1.29–2.60]), hypoechogenicity (DOR: 3.55 [1.47–7.30]), GBWT (DOR: 9.38 [1.47–32.20]), absence of hyperechoic spots (DOR: 4.23 [2.46–6.83]), and vascularity (DOR: 9.72 [5.81–15.30]). Of these, size ≥10 mm demonstrated the highest pooled sensitivity (0.79 [95% CI: 0.68–0.87]), whereas hypoechogenicity showed the highest pooled specificity (0.93 [95% CI: 0.82–0.98]). Conclusion Eight US imaging features (size ≥10 mm, sessile morphology, single polyp, coexisting gallstones, hypoechogenicity, GBWT, absence of hyperechoic spots, and vascularity) were significantly associated with the presence of neoplastic polyps.These features may facilitate the management of gallbladder polyps.

Objective: Evidence remains limited regarding whether Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) or modified RECIST (mRECIST) more reliably assesses treatment response in patients with hepatocellular carcinoma (HCC) receiving atezolizumab plus bevacizumab (Atezo/Bev). This study aimed to evaluate response patterns based on RECIST 1.1 and mRECIST, analyze inter-reader agreement, and assess their prognostic value for overall survival (OS) in patients with HCC receiving first-line Atezo/Bev. Materials and Methods: This retrospective study included patients with HCC treated with first-line Atezo/Bev between June 2020 and December 2022 at a tertiary center. Patients with at least one hypervascular hepatic target lesion were eligible. Two radiologists independently assessed treatment responses using RECIST 1.1 and mRECIST. Inter-reader agreement was evaluated using Cohen’s kappa coefficient. Time-dependent Cox regression analysis was performed, with radiologic response and progression treated as time-varying covariates. Prognostic discrimination was evaluated using Harrell’s concordance index (C-index). Results: A total of 207 patients were included (171 men; median age, 63 years; median follow-up, 10.7 months [range, 0.8– 46.4 months]; median OS, 10.7 months [95% confidence interval, 9.2–12.8 months]). mRECIST identified more responders than RECIST 1.1 (54.6% vs. 16.9%). RECIST 1.1 demonstrated excellent inter-reader agreement, whereas mRECIST showed substantial agreement (weighted kappa, 0.89 vs. 0.79). A significantly higher rate of dissociated responses was observed with mRECIST than with RECIST 1.1 (14.0% vs. 4.3%, P < 0.001). Both RECIST 1.1- and mRECIST-based responses and progression were independently associated with OS. Models incorporating RECIST 1.1 demonstrated slightly higher C-index values than those incorporating mRECIST (RECIST 1.1: 0.68 for response and 0.75 for progression; mRECIST: 0.65 and 0.70, respectively). Conclusion RECIST 1.1 is more reproducible and prognostically valuable for guiding treatment decisions in patients with HCC receiving first-line Atezo/Bev. However, this does not invalidate the use of mRECIST as a biological tumor response marker.

Background: The existing clinical subtype classification of basal cell carcinoma (BCC) does not adequately reflect tumor invasiveness or its relationship with histologic patterns. Objective: To suggest the upgrading classification of clinical subtype of BCC and evaluate its correlation with histologic subtypes and tumor invasiveness. Methods: This study enrolled 422 patients with 425 biopsy-proven BCC lesions. All of the patients were treated by Mohs micrographic surgery (MMS) at our hospital from January 2018 to October 2021. All BCCs were categorized according to upgrading clinical subtype classification we suggest: Basic subtypes (including nodular [N], papular [P], superficial-elevated [SE]/-flat [SF]/-depressed [SD] and infiltrative [I] subtype) and combined subtype. We conducted a retrospective study through medical record, clinical photographs, pathologic slide and MMS sheets. Results: The most common in basic subtypes was SE (23.1%), followed by N (22.1%) and I (12.0%) subtype. Nodulo-infiltrative (N-I) (8.7%) was the most common in combined subtype.In N, P, SE and SF subtype (non-aggressive group), the rate of tumor with pigmentation (63.1%) was high, non-aggressive pattern (91.4%) in histologic subtype was observed much more. In SD, I and combined subtype (aggressive group), pigmentation (24.0%) was relatively rare, aggressive and mixed pattern (74.4%) in histologic subtype was observed more. More wider surgical margin and more MMS stage number were required in aggressive group than non-aggressive group. Conclusion The upgrading classification of BCC clinical subtype can be not only described briefly and concretely for clinical appearance of BCCs but also highly correlated with histologic subtypes and tumor invasiveness.

Purpose: Due to its rarity, treatment guidelines for appendiceal cancer have traditionally followed those established for colorectal cancer, despite showing distinct histologic and clinical features. This study aimed to compare the clinicopathologic characteristics and long-term oncologic outcomes of appendiceal cancer with those of right-sided colon cancers. Methods: We retrospectively reviewed the records of patients with stage I–III appendiceal, cecal, or ascending colon cancer who underwent curative resection between 2010 and 2020 at our center. A 1:3:3 exact matching for age, sex, TNM stage, and adjuvant chemotherapy was performed. Survival outcomes were analyzed using the Kaplan-Meier and Cox regression methods. Results: Overall, 245 patients with appendiceal cancer (n = 35), ascending colon cancer (n = 105), and cecal cancer (n = 105) were analyzed. Appendiceal cancer exhibited a higher proportion of T4 tumors and fewer harvested lymph nodes compared with ascending or cecal cancers. The mean follow-up duration was 9.5 years. The 5- and 10-year overall survival rates were lower in appendiceal cancer (66.2% and 52.9%) than in ascending (91.2% and 78.4%) or cecal cancer (88.5% and 78.3%). Similarly, the 10-year disease-free survival rate was lower in appendiceal cancer (59.2%) compared with ascending (83.1%) and cecal cancers (78.4%). Cox regression analysis identified age (≥65 years), perforation, nodal metastasis, and lymphovascular invasion as independent predictors of poor prognosis. Conclusion Appendiceal cancer exhibited significantly worse long-term survival compared to cecal or ascending colon cancer. Tumor perforation, nodal metastasis, and lymphovascular invasion were adverse prognostic factors for overall and disease-free survival.