Background: Although coronavirus disease 2019 (COVID-19) vaccines have been distributed worldwide under emergency use authorization, the real-world safety profiles of mRNA vaccines still need to be clearly defined. We aimed to identify the overall incidence and factors associated with adverse events (AEs) following mRNA COVID-19 vaccination. Methods: We conducted web-based survey from December 2 to 10 in 2021 with a 2,849 nationwide sampled panel. Study participants were individuals who had elapsed at least twoweeks after completing two dosing schedules of COVID-19 vaccination aged between 18–49 years. We weighted the participants to represent the Korean population. The outcome was the overall incidence of AEs following mRNA COVID-19 vaccination and associated factors.We estimated the weighted odds ratios (ORs) using multivariable logistic regression models to identify the factors associated with AEs. Results: Of the 2,849 participants (median [interquartile range] age, 35 [27–42] years; 51.6% male), 90.8% (n = 2,582) for the first dose and 88.7% (n = 2,849) for the second dose reported AEs, and 3.3% and 4.3% reported severe AEs, respectively. Occurrence of AEs was more prevalent in mRNA-1273 (OR, 2.06; 95% confidence interval [CI], 1.59–2.67 vs. BNT162b2), female sex (1.88; 1.52–2.32), and those with dermatologic diseases (2.51; 1.32–4.77). History of serious allergic reactions (1.96; 1.06–3.64) and anticoagulant medication use (4.72; 1.92–11.6) were associated with severe AEs. Conclusion Approximately 90% of participants reported AEs following mRNA COVID-19 vaccination. Substantial factors, including vaccine type (mRNA-1273), female sex, and dermatologic diseases were associated with AEs. Our findings could aid policymakers in establishing vaccination strategies tailored to those potentially susceptible to AEs.

Purpose: Implant-based breast reconstruction is the most common reconstruction method used after mastectomy in breast cancer patients. Many studies have compared the smooth round implants and textured anatomical implants. This study aimed to compare the complications, including capsular contracture, between these two implants used in direct-toimplant (DTI) breast reconstruction. Methods: This retrospective chart review was performed using a prospectively maintained database from a single center. We identified patients who underwent mastectomy with DTI single-stage breast reconstruction at our hospital between August 2011 and June 2021. The overall complications, including capsular contracture, postoperative infection, seroma, hematoma, implant rupture, implant exposure, rippling, implant malposition, and nipple necrosis, were analyzed. Results: In total, 340 breasts of 323 patients were reconstructed by the DTI approach using either textured anatomical (n = 203) or smooth round (n = 137) implants. The incidence of overall complications and capsular contracture was significantly lower with smooth round implants than with textured anatomical implants. Multivariate analysis showed that smooth round implants were associated with a reduced risk of overall complications (odds ratio [OR], 0.465; 95% confidence interval [CI], 0.265–0.813) and capsular contracture (OR, 0.475; 95% CI, 0.235–0.962). Particularly, smooth round implants were associated with a decreased risk of overall complications in patients not receiving adjuvant chemotherapy and a decreased risk of capsular contracture in patients with body mass index < 25 kg/m2 and in those not receiving adjuvant radiotherapy. Conclusion Smooth round implants demonstrated a decreased risk of overall complications and capsular contracture when compared with textured anatomical implants. These results may be utilized in counseling patients regarding the advantages and disadvantages of smooth round implants in DTI breast reconstruction.

Kikuchi-Fujimoto disease (KFD) is an acute febrile disease that mainly involves histiocytic necrotizing lymphadenitis in children and young adults. Diagnosis of KFD is even more difficult if image-guided percutaneous biopsy is technically challenging. We present a case of clinically diagnosed KFD in an 11-year-old boy who presented with fever, abdominal pain, and mesenteric lymphadenopathy, resulting in a diagnostic challenge. Additionally, we conducted a systematic review, and our goal was to describe the spectrum of disease, therapy, and outcomes. We identified 15 cases of KFD with symptoms that mimicked mesenteric lymphadenitis. Reports from the Americas, Europe, and Asia were also included. Most patients were male, exhibited leukopenia and elevated inflammatory markers, and recovered without significant sequelae or complications. A high index of suspicion of KFD should be maintained in children presenting with prolonged fever and unusual manifestations, such as mesenteric lymphadenitis.

Background: Arsenic trioxide (ATO) is the standard treatment for relapsed acute promyelocytic leukemia (APL). However, consensus on post-remission therapies is still lacking. Methods: We evaluated 52 patients who experienced relapse following initial treatment of APL between 2000 and 2019 at Catholic Hematology Hospital. Among them, 41 patients received reinduction treatment, 30 with ATO-based regimen, whereas 11 with conventional intensive chemotherapy (IC). Results: The ATO reinduction group showed a significantly higher second molecular complete remission (mCR2) rate, superior neutrophil and platelet recovery, and a lower infection rate than the IC reinduction group. No significant differences were observed in survival outcomes after post-remission treatment among the ATO-based (N=19), autologous (N=12), and allogeneic (N=6) hematopoietic stem cell transplantation (HSCT) groups. In the ATO-based and autologous HSCT groups, among patients with mCR2 after ATO reinduction, nine and five patients experienced a second relapse, respectively (50.7% vs. 41.7%, P =0.878). Among these patients, seven received salvage allogeneic HSCT; six remained alive. The other seven patients received ATO without HSCT. Five died from disease progression, and two survived and have been in mCR2 since. Conclusion Post-remission treatment outcomes of patients with relapsed APL were not significantly different, regardless of the treatment option, suggesting the feasibility of ATO-based treatment without HSCT in mCR2. Allogeneic HSCT may be an effective salvage treatment modality for patients with a second relapse. Owing to a few cases of relapsed APL, multicenter prospective studies may help elucidate the efficacy of each post-remission treatment.

Background/Aims: Idiopathic multicentric Castleman disease (iMCD) comprises approximately 30% of all cases of Castleman disease. It is characterized by constitutional symptoms, enlarged lymph nodes at multiple anatomical sites, and laboratory test abnormalities, which are primarily related to the overproduction of interleukin 6 (IL-6). Siltuximab is a human-mouse chimeric immunoglobulin G1κ monoclonal antibody against human IL-6. In view of the limited treatment options for iMCD, this study aimed to evaluate the efficacy and safety of siltuximab in the management of this condition. Methods: In this real-world retrospective study, we administered siltuximab to 15 patients with iMCD who previously received conventional chemotherapy and/or steroid pulse therapy. The median time to a durable symptomatic response was 22 days (range, 17 to 56). The serum hemoglobin and albumin levels and erythrocyte sedimentation rates significantly normalized after the first 3 months of siltuximab treatment. Lymph node involution, assessed using imaging, was relatively gradual, demonstrating a complete or partial response at 6 months. Results: On an average, the improvements in clinical, laboratory, and radiologic parameters of iMCD in responders were observed after one, three, and eight cycles of siltuximab treatment, respectively. Siltuximab demonstrated a favorable safety profile, and prolonged treatment was well-tolerated. Conclusions Despite the small sample size of the present study, the results are encouraging and demonstrate the potential of siltuximab as the first-line treatment of iMCD. Further large multicenter studies are needed to evaluate the clinical outcomes and adverse events associated with siltuximab.

Purpose: To compare differences between the original criteria for diagnosis of ocular sarcoidosis (OS) (first International Workshop for OS [IWOS] 2009) and the revised criteria (sixth IWOS 2017), and their clinical usefulness when assessing OS in Korean patients. Methods: We analyzed patients with suspected OS who visited our tertiary referral ophthalmological and pulmonary clinic from 2007 to 2018. We diagnosed patients using both sets of criteria. Blood test and biopsy data (collected by physicians) and slit-lamp, fundus, and fluorescein angiography data (collected by ophthalmologists) were reviewed. Results: Thirty-four patients were diagnosed using both criteria. Of 32 patients who underwent biopsies, 31 had OS (96.87%). Using either set of criteria, 31 patients were diagnosed with definite OS and two with presumed OS. One patient diagnosed with possible OS using the previous criteria was diagnosed with presumed OS using the revised criteria. The new criteria add the lysozyme level, the CD4/CD8 ratio, and positron emission tomography imaging data to the old criteria and add the descriptors “presumed OS” and “probable OS”. There is no need to use the revised criteria in Korea; the biopsy and imaging data are adequately diagnostic. Conclusions IWOS revised the OS diagnostic criteria by adding new parameters. However, this was unnecessary for Korea, where the biopsy and imaging data are adequately diagnostic.

Background: Postoperative thyroid stimulating hormone (TSH) suppression therapy is recommended for patients with intermediate- and high-risk differentiated thyroid cancer to prevent the recurrence of thyroid cancer. With the recent increase in small thyroid cancer cases, the extent of resection during surgery has generally decreased. Therefore, questions have been raised about the efficacy and long-term side effects of TSH suppression therapy in patients who have undergone a lobectomy. Methods: This is a multicenter, prospective, randomized, controlled clinical trial in which 2,986 patients with papillary thyroid cancer are randomized into a high-TSH group (intervention) and a low-TSH group (control) after having undergone a lobectomy. The principle of treatment includes a TSH-lowering regimen aimed at TSH levels between 0.3 and 1.99 μIU/mL in the low-TSH group. The high-TSH group targets TSH levels between 2.0 and 7.99 μIU/mL. The dose of levothyroxine will be adjusted at each visit to maintain the target TSH level. The primary outcome is recurrence-free survival, as assessed by neck ultrasound every 6 to 12 months. Secondary endpoints include disease-free survival, overall survival, success rate in reaching the TSH target range, the proportion of patients with major cardiovascular diseases or bone metabolic disease, the quality of life, and medical costs. The follow-up period is 5 years. Conclusion The results of this trial will contribute to establishing the optimal indication for TSH suppression therapy in low-risk papillary thyroid cancer patients by evaluating the benefit and harm of lowering TSH levels in terms of recurrence, metabolic complications, costs, and quality of life.

In November 2021, 14 international travel-related severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant of concern (VOC) patients were detected in South Korea. Epidemiologic investigation revealed community transmission of the omicron VOC. A total of 80 SARS-CoV-2 omicron VOC-positive patients were identified until December 10, 2021 and 66 of them reported no relation to the international travel.There may be more transmissions with this VOC in Korea than reported.

Background: Postoperative thyroid stimulating hormone (TSH) suppression therapy is recommended for patients with intermediate- and high-risk differentiated thyroid cancer to prevent the recurrence of thyroid cancer. With the recent increase in small thyroid cancer cases, the extent of resection during surgery has generally decreased. Therefore, questions have been raised about the efficacy and long-term side effects of TSH suppression therapy in patients who have undergone a lobectomy. Methods: This is a multicenter, prospective, randomized, controlled clinical trial in which 2,986 patients with papillary thyroid cancer are randomized into a high-TSH group (intervention) and a low-TSH group (control) after having undergone a lobectomy. The principle of treatment includes a TSH-lowering regimen aimed at TSH levels between 0.3 and 1.99 μIU/mL in the low-TSH group. The high-TSH group targets TSH levels between 2.0 and 7.99 μIU/mL. The dose of levothyroxine will be adjusted at each visit to maintain the target TSH level. The primary outcome is recurrence-free survival, as assessed by neck ultrasound every 6 to 12 months. Secondary endpoints include disease-free survival, overall survival, success rate in reaching the TSH target range, the proportion of patients with major cardiovascular diseases or bone metabolic disease, the quality of life, and medical costs. The follow-up period is 5 years. Conclusion The results of this trial will contribute to establishing the optimal indication for TSH suppression therapy in low-risk papillary thyroid cancer patients by evaluating the benefit and harm of lowering TSH levels in terms of recurrence, metabolic complications, costs, and quality of life.

Purpose: To compare differences between the original criteria for diagnosis of ocular sarcoidosis (OS) (first International Workshop for OS [IWOS] 2009) and the revised criteria (sixth IWOS 2017), and their clinical usefulness when assessing OS in Korean patients. Methods: We analyzed patients with suspected OS who visited our tertiary referral ophthalmological and pulmonary clinic from 2007 to 2018. We diagnosed patients using both sets of criteria. Blood test and biopsy data (collected by physicians) and slit-lamp, fundus, and fluorescein angiography data (collected by ophthalmologists) were reviewed. Results: Thirty-four patients were diagnosed using both criteria. Of 32 patients who underwent biopsies, 31 had OS (96.87%). Using either set of criteria, 31 patients were diagnosed with definite OS and two with presumed OS. One patient diagnosed with possible OS using the previous criteria was diagnosed with presumed OS using the revised criteria. The new criteria add the lysozyme level, the CD4/CD8 ratio, and positron emission tomography imaging data to the old criteria and add the descriptors “presumed OS” and “probable OS”. There is no need to use the revised criteria in Korea; the biopsy and imaging data are adequately diagnostic. Conclusions IWOS revised the OS diagnostic criteria by adding new parameters. However, this was unnecessary for Korea, where the biopsy and imaging data are adequately diagnostic.