Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Purpose: Current clinical practices favor less or no thyroid-stimulating hormone (TSH) suppression for low- to intermediate-risk thyroid cancer patients who receive thyroid lobectomy. The association of TSH suppression on healthrelated quality of life (HR-QoL) in patients after thyroid lobectomy is not well studied. This study aimed to evaluate the effect of TSH suppression on patient HR-QoL after thyroid lobectomy. Methods: This study included patients enrolled in an ongoing, multicenter, randomized controlled study investigating the effects of TSH suppression. Patients were randomized to either the low-TSH group (TSH target range, 0.3–1.99 μIU/ mL) or the high-TSH group (TSH target range, 2.0–7.99 μIU/mL). The HR-QoL, hyperthyroidism symptom, and depression symptom questionnaires performed preoperatively and 2 weeks and 3 months postoperatively were evaluated. Results: Total of 669 patients (low-TSH group, 340; high-TSH group, 329) were included. Although total HR-QoL score changes were not different between the 2 groups, the high-TSH group had a significantly higher score in the physical domain at postoperative 3 months (P = 0.046). The 2 groups did not have significant differences in hyperthyroidism and depression scores. Conclusion In the short-term postoperative period, the physical HR-QoL scores in thyroid lobectomy patients were better when they did not receive TSH suppression. This study suggests the importance of considering HR-QoL when setting TSH suppression targets in thyroid lobectomy patients.

Background/Aims: To overcome the technical limitations of classic endoscopic resection for gastric gastrointestinal stromal tumors (GISTs), various methods have been developed. In this study, we examined the role and feasibility of clip-and-cut procedures (clip-and-cut endoscopic full-thickness resection [cc-EFTR]) for gastric GISTs. Methods: Medical records of 83 patients diagnosed with GISTs after endoscopic resection between 2005 and 2021 were retrospectively reviewed. Moreover, clinical characteristics and outcomes were analyzed. Results: Endoscopic submucosal dissection (ESD) and cc-EFTR were performed in 51 and 32 patients, respectively. The GISTs were detected in the upper third of the stomach for ESD (52.9%) and cc-EFTR (90.6%). Within the cc-EFTR group, a majority of GISTs were located in the deep muscularis propria or serosal layer, accounting for 96.9%, as opposed to those in the ESD group (45.1%). The R0 resection rates were 51.0% and 84.4% in the ESD and cc-EFTR groups, respectively. Seven (8.4%) patients required surgical treatment (six patients underwent ESD and one underwent cc-EFTR,) due to residual tumor (n=5) and post-procedure adverse events (n=2). Patients undergoing R0 or R1 resection did not experience recurrence during a median 14-month follow-up period, except for one patient in the ESD group. Conclusions cc-EFTR displayed a high R0 resection rate; therefore, it is a safe and effective therapeutic option for small gastric GISTs.

Background/Aims: There is limited knowledge regarding the management of duodenal subepithelial lesions (SELs) owing to a lack of understanding of their natural course. This study aimed to assess the natural course of asymptomatic duodenal SELs and provide management recommendations. Methods: Patients diagnosed with duodenal SELs and followed up for a minimum of 6 months were retrospectively investigated. Results: Among the 443,533 patients who underwent esophagogastroduodenoscopy between 2008 and 2020, duodenal SELs were identified in 0.39% (1,713 patients). Among them, 396 duodenal SELs were monitored for a median period of 72.5 months (interquartile range, 37.7–111.3 mo). Of them, 16 SELs (4.0%) showed substantial changes in size or morphology at a median follow-up of 35.1 months (interquartile range, 21.7–51.4 mo). Of these SELs with substantial changes, tissues of two SELs were acquired using endoscopic ultrasound-guided fine needle aspiration biopsy: one was a lipoma and the other was non-diagnostic. Three SELs were surgically or endoscopically removed; two were diagnosed as gastrointestinal stromal tumors, and one was a lipoma. An initial size of 20 mm or larger was associated with substantial changes during follow-up (p = 0.016). Conclusions While the majority of duodenal SELs may not exhibit substantial interval changes, regular follow-up with endoscopy may be necessary for cases with an initial size of 20 mm or larger, considering a possibility of malignancy.

Purpose: This article was to collect data on the safety of coronavirus disease 2019 (COVID-19) vaccines in children with underlying medical conditions. Methods: We constructed a prospective cohort of children and adolescents aged 5 to 19 years who had received at least one dose of COVID-19 vaccine. Patients diagnosed with and treated for chronic kidney disease, autoimmune disease, or other chronic conditions at the Seoul National University Children’s Hospital were recruited from June to December 2022. A mobile survey questionnaire was sent to their guardians. The presence of adverse events on the day (day 0), 3 weeks (day 21), and 6 months (day 180) after the 1st dose of COVID-19 vaccine was recorded by the guardians. Results: A total of 73 children participated. The median age was 14 years, and 64.4% of the patients were male. On the day of immunization, 65.8% of the patients reported at least one adverse event. Pain at the injection site, fatigue, headache, arthralgia, and myalgia were the most common symptoms. The prevalence of adverse events decreased over time (65.8% on day 0, 27.4% between days 0 and 21, and 24.6% between days 21 and 180). Severe acute respiratory syndrome coronavirus 2 infection after the 1st dose occurred in 17 patients (23.3%) and one of the patients (5.88%) was hospitalized due to infection. Conclusions Adverse events after COVID-19 vaccination were generally mild in children and adolescents with underlying medical conditions. Our findings provide evidence for the safety of COVID-19 vaccination in the vulnerable pediatric population.

Colonic interposition is the main procedure used in esophageal reconstruction. We report a rare case of simultaneous treatment of an anastomotic site stricture and a neoplasm in the interpositioned colon. A 69-year-old female visited our outpatient clinic with symptoms of progressive dysphagia for 1 year. At the age of 30 years, the patient underwent esophagectomy with retrosternal colonic interposition because of severe esophageal burns after chemical ingestion. Upper gastrointestinal endoscopy revealed stricture at the anastomosis site and a 10-mm flat elevated high-grade dysplasia in the interpositioned colon. First, through-the-scope balloon dilatation was performed for strictures. However, stenosis was observed during the second upper gastrointestinal endoscopy session.Therefore, a second session of through-the-scope balloon dilatation was performed, and simultaneously, endoscopic submucosal dissection was also successfully performed. After 2 months of follow-up, stenosis persisted; consequently, balloon dilatation was performed. No recurrence of neoplasm was confirmed endoscopically. Through-the-scope balloon dilatation of the stricture site and simultaneous endoscopic submucosal dissection of the neoplasm in the interpositioned colon were successfully performed.

Purpose: No standard salvage regimen is available for relapsed or refractory sarcoma. We investigated the efficacy and toxicity of the vincristine, irinotecan, and temozolomide combination (VIT) for relapsed or refractory sarcomas of variable histology in children and young adults. Materials and Methods: We retrospectively reviewed data from the relapsed or refractory sarcoma patients who were treated with VIT. The VIT protocol was given every 3 weeks as follows: vincristine, 1.5 mg/m2 intravenously on day 1, irinotecan, 50 mg/m2/day intravenously on days 1-5, and temozolomide, 100 mg/m2/day orally on days 1-5. Results: A total of 26 patients (12 males) with various sarcoma histology were included in the study. Most common diagnosis was rhabdomyosarcoma (n=8) followed by osteosarcoma (n=7). Median age at the start of VIT was 18.5 years (range, 2.0 to 39.9). VIT was delivered as 2nd to 7th line of treatment, with 4th line most common (9/26, 34.6%). Median number of VIT courses given was 3 (range, 1 to 18). Of the 25 evaluable patients, there was two partial response (PR) and 11 stable disease (SD) with an overall control rate (complete remission+PR+SD) of 52%. PR was seen in one (50%) of the two evaluable patients with Ewing sarcoma and one (14.3%) of the seven patients with osteosarcoma. Overall survival and progression-free survival rates were 79.3% and 33.9% at 1 year, and 45.5% and 25.4% at 2 years, respectively. There was no treatment-related mortality. Conclusion The VIT regimen was effective and relatively safe in our cohort of sarcoma patients.