1.Impact of Tumor Bilaterality and Multifocality in Predicting Recurrence of Papillary Thyroid Carcinoma: A Retrospective Cohort Study
Eunji KIM ; Jun Hyun PARK ; Ji-Young PARK ; Jin Hyang JUNG ; Sang-Woo LEE
Endocrinology and Metabolism 2026;41(2):288-299
Background:
This study investigated the prognostic value of bilaterality and multifocality in papillary thyroid carcinoma (PTC) recurrence, aiming to inform optimal surgical strategies.
Methods:
In this retrospective cohort, 1,966 patients who underwent total thyroidectomy for PTC (2011–2014) were categorized into four groups according to tumor multifocality and bilaterality confirmed by postoperative histopathology: group 1, unilateral solitary; group 2, unilateral multifocal; group 3, bilateral solitary; group 4, bilateral multifocal. Clinicopathologic features and clinical outcomes were compared across these groups.
Results:
Group 4 exhibited the highest prevalence of BRAFV600E positivity, nodal metastases, and recurrence. Both bilaterality and multifocality were associated with more aggressive clinicopathologic characteristics. Recurrence risk increased with the number of tumor foci, with the odds ratio (OR) significantly elevated for more than five foci. Satellite pattern was strongly linked to recurrence (OR, 19.49; P<0.001). While tumor multifocality (≥5 foci) and bilaterality were associated with recurrence in univariate analyses, these associations were not independent after adjustment. Kaplan-Meier analysis demonstrated the lowest recurrence-free survival (RFS) in group 4. Patients with bilateral disease had significantly lower RFS than those with unilateral disease (P=0.003), whereas multifocality did not significantly affect RFS compared to solitary disease (P=0.095).
Conclusion
Tumor bilaterality, multifocality (≥5 foci), and satellite pattern were associated with aggressive features and higher recurrence risk. Although not independent predictors, these factors may serve as useful surrogate markers of aggressive disease biology and help guide personalized surgical strategies in patients with PTC.
2.Normal liver enzymes do not indicate safety from alcohol-related liver disease: evidence from a Korean nationwide cohort
Yeon Woo OH ; Jun Young PARK ; Eun-Cheol PARK
Epidemiology and Health 2026;48(1):e2026004-
OBJECTIVES:
This study examined whether individuals with consistently normal liver enzyme levels are protected from alcohol-related liver disease and investigated whether heavy drinking increases liver disease risk independent of normal biomarker status.
METHODS:
We conducted a nationwide cohort study using Korean National Health Insurance Service data (2002–2019), including 19,035 participants aged ≥40 years who maintained normal liver enzyme levels (aspartate aminotransferase ≤40 μ/L, alanine aminotransferase ≤40 μ/L, gamma-glutamyl transferase ≤63 μ/L for men and ≤35 μ/L for women) across multiple examinations conducted between 2002 and 2008. Participants were categorized as abstainers (≤1 time/mo), moderate drinkers (≤2 times/wk), and heavy drinkers (≥3 times/wk). Primary outcomes included incident liver disease identified using diagnostic codes. Cox proportional hazards models were used to estimate hazard ratios (HRs), with age-stratified analyses performed.
RESULTS:
Heavy drinkers demonstrated a significantly higher risk of liver disease than abstainers (HR, 1.73; 95% confidence interval [CI], 1.40 to 2.14), whereas moderate drinkers showed no significant association (HR, 1.06; 95% CI, 0.94 to 1.19). Consistent patterns emerged for middle-aged adults (40–69 years), with attenuated effects among participants aged ≥70 years. When alcoholic liver disease was analyzed specifically, both moderate (HR, 1.29; 95% CI, 1.05 to 1.58) and heavy drinkers (HR, 2.86; 95% CI, 2.09 to 3.91) exhibited significantly increased hazards.
CONCLUSIONS
Despite normal liver enzyme levels, heavy alcohol consumption was associated with a significantly increased risk of liver disease. These findings challenge current reactive screening paradigms relying solely on biomarker abnormalities and support proactive alcohol counseling regardless of enzyme results. More sensitive strategies are needed for early detection of alcohol-related liver injury.
3.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
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.
4.Comparative Analysis of Multiple Combined Structure Transmit Arrays for 10.5 Tesla Human Brain Imaging
Young Don PARK ; Jun Moo KWAK ; Myung Kyun WOO
Investigative Magnetic Resonance Imaging 2026;30(1):38-46
Purpose:
To evaluate several hybrid multi-element configurations to enhance B1+ effi-ciency, defined as the transmit magnetic field generated by the radiofrequency (RF) coil normalized by the net input power, and spatial coverage for 10.5 tesla (T) human brain imaging.
Materials and Methods:
Finite-difference time-domain simulations were performed using an anatomically detailed human head model to assess circularly polarized B1+ fieldsgenerated by 8-channel loop, dipole antenna, and monopole and dipole hybrid antenna (MDH) arrays. These baseline designs were extended to 16-channel arrays combining loops with dipole antennas or MDHs and to interleaved MDH-based arrays incorporating axially displaced dipole or monopole antennas.
Results:
The 8-channel MDH array yielded the highest central B1+ efficiency, exceedingloop and dipole antenna arrays by 38.5% and 33.3%, respectively, but peripheral coverage remained limited. The 16-channel loop + dipole antenna and loop + MDH arrays improved overall B1+ efficiency by up to 28.9% relative to their 8-channel counterparts.Interleaved combined structure arrays further enhanced peripheral excitation and superior–inferior coverage, with the T-shaped monopole antenna + MDH configuration achieving a high central efficiency.
Conclusion
MDH-centered combined structure arrays effectively balance deep-field efficiency and peripheral coverage at 10.5 T. Interleaving monopole antenna-type elements beneath MDHs provides additional improvement and represents a promising design pathway for achieving more uniform excitation in 10.5 T brain imaging.
5.Resting-State Electroencephalography as a Neurophysiological Marker Complementing Clinician-Rated Dementia Severity
Hyeonjin KIM ; Da Young OH ; Hahyun LEE ; Su Mi PARK ; Jun-Young LEE
Journal of Korean Geriatric Psychiatry 2026;30(1):28-34
Objective:
Reliable staging of dementia is critical for both clinical practice and research. Although the Clinical Dementia Rating (CDR) is widely used to assess dementia severity, it is subject to subjectivity and inter-rater variability. Resting-state electroencephalography (EEG) may provide objective neurophysiological information associated with clinical severity.
Methods:
Resting-state EEG data from 600 adults aged ≥60 years in Korea were analyzed. Relative power spectral density was extracted from 19 electrodes across six frequency bands. Ordinal logistic regression and linear regression analyses exam-ined associations between resting-state EEG spectral features and CDR Global and CDR Sum of Boxes (CDR-SB) scores. All models adjusted for age, sex, education, and depressive symptoms, with false-discovery-rate correction.
Results:
Ordinal logistic regression demonstrated that higher resting-state theta-band EEG power was significantly associatedwith greater CDR Global severity, particularly in frontal, temporal, central, and parietal regions. Consistently, linear regressionanalyses revealed that higher CDR-SB scores were associated with increased theta in widespread cortical areas. No significantassociations were observed in other frequency bands.
Conclusion
EEG spectral slowing—marked by elevated theta power—was consistently related to CDR-defined dementia se-verity. Resting-state EEG can potentially serve as an objective neurophysiological correlate that informs clinician-rated staging and enhances the reliability of dementia severity assessment.
6.Clinical Characteristics and Survival Data of Korean Malignant Melanoma in Situ:A Single-Center Experience with 156 Patients (2008∼2021)
Jin Seon BANG ; Jin Ho KIM ; Do Young PARK ; Seok-Jong LEE ; Nam Gyoung HA ; Dae-Lyong HA ; Yong Hyun JANG ; Weon Ju LEE ; Jun Young KIM
Korean Journal of Dermatology 2026;64(1):10-17
Background:
Although patients with malignant melanoma in situ (MIS) have a high survival rate, a risk of recurrence or upstaging remains. Thus, a comprehensive understanding of its prognosis is essential for optimal patient management.
Objective:
To investigate the clinical characteristics and survival outcomes of Korean patients with MIS.
Methods:
We retrospectively analyzed the medical records and photographs of patients with MIS treated at a single tertiary center between 2008 and 2021. Clinical features, including diagnosis, treatment, recurrence, and mortality, were examined.
Results:
A total of 156 patients with MIS were included, with a mean age of 59.3 years. The most common subtype was acral lentiginous melanoma (80.8%). Delayed diagnosis was associated with subungual MIS (SUMis; p <0.05). Among the subtypes other than SUMis, 77.3% met three or more of the ABCD criteria for melanoma.Hutchinson’s sign was observed in 67.3% of cases of SUMis. Ulceration was present in only two cases (1.3%).Recurrence occurred in nine patients (5.8%), with four (2.6%) experiencing relapse after 5 years. Upstaging was observed in two patients (1.3%) due to intralymphatic or regional nodal metastasis occurring at 19 and 10 months post-treatment. The 5-year and 10-year melanoma-specific/overall survival rates were 100.0/96.9% and 100.0/89.0%, respectively.
Conclusion
Although the survival rates of patients with MIS are high, long-term and close follow-up after treatment is essential because of the possibility of late recurrence and rare instances of intralymphatic or regional nodal metastasis. Additionally, the presence of clinical ulceration is highly suggestive of invasive melanoma.
7.Clinical Features and Prognostic Factors of Indirect Traumatic Optic Neuropathy
Jun HEO ; Jungyul PARK ; Hee-Young CHOI
Journal of the Korean Ophthalmological Society 2026;67(6):201-212
Purpose:
Our study identified prognostic factors affecting visual outcomes in patients with unilateral indirect traumatic optic neuropathy (TON), determined the risk of legal blindness, and assessed changes in visual acuity, visual fields, retinal structure, and the therapeutic effect of high-dose corticosteroid treatment.
Methods:
We retrospectively reviewed the medical records of 52 patients (52 eyes) diagnosed with TON between 2014 and 2023. Patients were categorized into two groups according to the final best-corrected visual acuity (BCVA): Group 1 (BCVA ≥0.1) and Group 2 (BCVA <0.1). Prognostic factors were analyzed using logistic regression, and receiver operating characteristic curve analysis was performed to determine optimal cutoff values. Longitudinal changes in visual acuity, visual field index (VFI), and retinal structural parameters were assessed using a generalized linear mixed model.
Results:
Factors significantly associated with Group 1 included the absence of intracranial hemorrhage, administration of high-dose steroids within 24 h, and better logMAR visual acuity and VFI within 4 weeks post-trauma. In multivariate analysis, VFI within 4 weeks remained significantly associated with favorable visual outcomes (p = 0.008). The optimal VFI cutoff value for predicting a good prognosis was 13%, yielding a sensitivity of 90% and specificity of 93.3%. Visual acuity outcomes over time differed significantly according to the timing of high-dose steroid administration.
Conclusions
VFI within 4 weeks after injury was the most reliable prognostic indicator, demonstrating high sensitivity and specificity for predicting legal blindness. Early administration of high-dose steroids within 24 h helped prevent visual deterioration. These findings emphasize the importance of early quantitative assessment of visual function and prompt therapeutic intervention to guide treatment strategies in patients with TON.
8.Molecular Epidemiology of Extended-spectrum β-Lactamase-producing Escherichia coli in South Korea: A Korean Global Antimicrobial Resistance Surveillance System Report
Dokyun KIM ; SungYoung LEE ; Jun Sung HONG ; Min Hyuk CHOI ; Hyun Soo KIM ; Young Ree KIM ; Young Ah KIM ; Young UH ; Kyeong Seob SHIN ; Jeong Hwan SHIN ; Jeong Su PARK ; Kyoung Un PARK ; Soo Hyun KIM ; Jong Hee SHIN ; Jungsik YU ; Seok Hoon JEONG
Annals of Laboratory Medicine 2026;46(1):72-82
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.
9.Detection of Fusion Genes Using RNA Sequencing in Acute Leukemia
Hyun-Young KIM ; Boram KIM ; Min-Seung PARK ; Jong-Ho PARK ; Hee Young JU ; Keon Hee YOO ; Jun Ho JANG ; Chul Won JUNG ; Hee-Jin KIM
Annals of Laboratory Medicine 2026;46(3):257-269
Background:
Fusion genes are major drivers of acute leukemia. Conventional diagnostics are limited in detecting the diverse fusions included in recently updated acute leukemia classifications. We evaluated the fusion detection performance of RNA sequencing (RNAseq) compared with that of conventional diagnostics in patients with acute leukemia.
Methods:
We retrospectively obtained the data of 101 patients with acute leukemia who underwent conventional diagnostics (i.e., karyotyping, FISH, or multiplex reverse transcription PCR) at diagnosis at Samsung Medical Center, Seoul, Korea, between September 2022 and September 2023. Whole RNA-seq was performed using the Illumina Stranded mRNA Prep kit (Illumina, San Diego, CA, USA). The concordance, sensitivity, and specificity of RNA-seq for fusion gene detection were compared with those of conventional diagnostics.
Results:
RNA-seq helped identify 52 fusion genes in 51 (50.5%) of 101 patients, with detection rates of 40.7%, 70.3%, 37.5%, and 50% in acute myeloid leukemia, B-cell acute lymphoblastic leukemia, T-cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia, respectively. RNA-seq showed 83.3% sensitivity and 80.8% concordance with conventional diagnostics; it missed eight fusions, likely because of low transcript abundance or enhancer hijacking. RNA-seq also helped clarify three previously unspecified rearrangements and detected 12 fusions (21.4%) in 56 cases that tested negative with conventional diagnostics, including four novel (KMT2A::THAP12 , RUNX1::PRPF19 , MLLT10::UBE2L6, and FUS::ZNF362) and three rare (HNRNPH1::ERG, RUNX1::USP42, and ETV6::NCOA2) fusions.
Conclusions
This was the first study to evaluate the performance of whole RNA-seq in fusion detection in patients with acute leukemia in Korea. Incorporating RNA-seq into diagnostic workflows may facilitate earlier and more precise therapeutic decisions and improve prognostic assessment in patients with acute leukemia.
10.Lateral Closing Wedge Supramalleolar Osteotomy with Inframalleolar Correction as a Joint-Preserving Procedure for Valgus Ankle Osteoarthritis: A Case Report
Ju Hwan PARK ; Jin Soo SUH ; Ji-Ye KIM ; Jun Young CHOI
Journal of Korean Foot and Ankle Society 2026;30(2):73-79
A medial closing wedge supramalleolar osteotomy, along with corrections for pes plano-valgus, including medial displacement calcaneal osteotomy, and deltoid ligament repair or reconstruction, is most commonly considered for the joint-preserving surgery of valgus ankle arthritis. In cases of ‘opposing coronal plane deformities,’ however, where the tibial plafond is varus-aligned to the long axis of the tibia and the ground, while the talus is conversely valgus-aligned, medial closing wedge supramalleolar osteotomy may paradoxically risk exacerbating the valgus ankle arthritis. This paper reports the radiological and clinical outcomes of an otherwise healthy, physically active 55-year-old male patient with valgus ankle arthritis and opposing coronal-plane deformities, along with a literature review. The patient underwent joint-preserving surgery consisting of lateral closing wedge supramalleolar osteotomy, fibular osteotomy, medial displacement calcaneal osteotomy, and deltoid ligament augmentation with suture tape. This paper discusses the critical considerations and surgical precautions necessary when deciding on joint-preserving procedures for valgus ankle arthritis.

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