1.Transformation of Pleomorphic Xanthoastrocytoma with Germline ATM Mutation into a SMARCB1-Deficient Rhabdoid Tumor: A Case Report
Hyeonseung LEE ; Hyun Jin PARK ; Bo Kyung KIM ; Kyung Taek HONG ; Hyoung Jin KANG ; Sung-Hye PARK ; Ji Hoon PHI ; June-Young KOH ; Jung Yoon CHOI
Clinical Pediatric Hematology-Oncology 2026;33(1):34-38
Secondary rhabdoid tumors (RTs) with atypical teratoid/rhabdoid tumor-like features rarely arise from, or coexist with, pleomorphic xanthoastrocytomas (PXAs), and their clinicopathological and molecular characteristics remain poorly understood. We report a 17-year-old girl with a temporal lobe mass that, upon gross total resection, pathologically contained both RT and PXA components. Immunohistochemistry revealed loss of INI1 expression restricted to the RT component, while the PXA area retained INI1. Next-generation sequencing identified a shared BRAF::TRIM24 fusion and homozygous deletion of CDKN2A/2B in both components, indicating a shared clonal origin. Additionally, a germline ATM frameshift mutation (c.5288_5289insGA) was identified in both tumor components, making the first such report in central nervous system tumors. SMARCB1 loss was confined to the RT component, further supporting the hypotheses of clonal evolution and secondary transformation. Despite gross total resection, craniospinal irradiation, and chemotherapy, the patient developed rapid leptomeningeal dissemination and died 5 months after surgery. This case provides clinicopathological and molecular evidence for clonal evolution and secondary transformation of PXA into an RT. The presence of germline ATM mutation may have therapeutic and biological relevance. Further studies are required to clarify the pathogenesis and optimal management of these rare and aggressive tumors.
2.Early Onset, High Comorbidity Burden, and Regional Disparities of CADASIL:A Nationwide Cohort Study in South Korea
Ju-Yeun LEE ; Minwoo LEE ; Jae-Sung LIM ; Mi Sun OH ; Kyung-Ho YU ; Young Eun KIM ; Hyeo-Il MA ; Yun Jin KIM ; Jong Ho PARK ; Young Hee JUNG
Journal of Clinical Neurology 2026;22(2):172-182
Background:
and Purpose To compare the epidemiological and clinical features of the rare patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with age- and sex-matched controls in a nationwide cohort from South Korea.
Methods:
This observational cohort study analyzed newly diagnosed CADASIL patients aged at least 20 years and matched controls using data from the National Health Information Database for 2004–2022. The cumulative incidence of CADASIL was assessed by age and sex, and compared between regions. Neurologic and systemic diseases were compared between the CADASIL and control groups.
Results:
The study analyzed 816 CADASIL patients and 816 age- and sex-matched controls aged 56.8±15.2 years (mean±standard deviation), among whom 48.3% were male. The cumulative incidence of CADASIL was 1.86 per 100,000 people (95% confidence interval [CI]=1.85– 1.87 per 100,000), and peaked at 60–69 years of age. In terms of regional distribution, the incidence was highest for Jeju, at 39.67 per 100,000 (95% CI 37.84–41.49 per 100,000). Neurologic diseases were more frequent in CADASIL patients, including Alzheimer’s disease (33.1% vs.20.0%), vascular dementia (84.9% vs. 5.0%), epilepsy (34.6% vs. 15.9%), stroke (70.7% vs. 27.6%), parkinsonism (18.9% vs. 11.0%), and depression (60.8% vs. 44.9%). Systemic diseases such as diabetes mellitus (78.9% vs. 68.9%) were also more common in CADASIL patients, while cancer (27.9% vs. 38.7%) and myocardial infarction (10.0% vs. 13.6%) were less common than in controls. The onset ages of all diseases were lower in CADASIL patients.
Conclusions
This study has provided a precise nationwide estimate of the CADASIL incidence and its regional distribution in South Korea. CADASIL patients showed higher incidence rates and earlier onsets of diverse clinical manifestations.
3.A Position Paper on Lipoprotein(a) From the Lipoprotein(a) Task Force of the Korean Society of Lipid and Atherosclerosis: Current Evidence, Clinical Applications, and Future Directions
Youngwoo JANG ; Jang Hoon LEE ; Sang-Guk LEE ; Hun Jee CHOE ; Sang Min PARK ; In-Kyung JEONG ; Byung Jin KIM ;
Journal of Lipid and Atherosclerosis 2026;15(1):2-25
Lipoprotein(a) [Lp(a)] is a genetically determined risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve stenosis (CAVS), with plasma levels largely unaffected by lifestyle modification or conventional lipid-lowering therapy. Although international guidelines increasingly recognize Lp(a) as a risk-enhancing factor, in many Asian populations thresholds for high Lp(a) and treatment strategies remain undefined.This Korean position paper, developed by the Lp(a) Task Force of the Korean Society of Lipid and Atherosclerosis, presents an evidence-based summary of the pathophysiology, clinical relevance, and therapeutic landscape surrounding Lp(a), with a focus on Koreanspecific data. It reviews the genetic architecture of Lp(a), ethnic variability in concentrations, and its mechanistic roles in inflammation, thrombosis, and calcification. Based on large Korean cohorts, a 3-tiered classification is proposed of normal (<30 mg/dL), borderline high (30–49 mg/dL), and high (≥50 mg/dL), harmonizing global thresholds with local data. The document also highlights the limitations of current Lp(a) assays in Korea, and calls for standardized, isoform-insensitive testing. Novel therapeutics, including antisense oligonucleotides, small interfering RNAs, and small molecular inhibitors, have shown promising Lp(a)-lowering effects, with multiple phase 3 trials currently ongoing, or in planning. Given the unmet clinical need, the paper recommends incorporating Lp(a) into cardiovascular risk assessment, and calls for Korean-specific longitudinal studies, national screening strategies, and participation in clinical trials. These efforts will help clarify Lp(a)-associated risk in Korean patients and guide the adoption of future targeted therapies.
4.Prosthetic rehabilitation of traumatized maxillary anterior teeth using a digital workflow: a case report
Jong-Hyun SHIN ; Sang-Ah LEE ; Lee-Ra CHO ; Chan-Jin PARK ; Kyung-Ho KO ; Yoon-Hyuk HUH
The Journal of Korean Academy of Prosthodontics 2026;64(1):84-94
The maxillary anterior region is critical for esthetics and function, requiring precise analysis and restoration when damaged by trauma. This case report presents the restorative process using a digital workflow for a patient with anterior trauma. A 22-year-old female exhibited fractures and extrusive luxation of maxillary central incisors, diagnosed with pulp necrosis. After endodontic treatment, intraoral and facial scans were performed, and provisional and definitive restorations were digitally designed. Various shade-matching techniques were employed to achieve natural esthetics. The definitive prosthesis improved harmony between the incisal edge and lower lip, as well as tooth axis, length, and zenith position, fulfilling the patient’s esthetic demands. This case suggests that combining digital technology and gingivectomy with a minimally invasive approach enables esthetic and functional restoration of the maxillary anterior region.
5.Macro-Aspartate Aminotransferase Elevation in a Patient with Chronic Hepatitis B
Nae-Yun HEO ; Jae-Hoon KIM ; Seungha PARK ; Joon Hyuk CHOI ; Tae Oh KIM ; Jin LEE ; Yong Eun PARK ; Kyung Ran JUN
The Korean Journal of Gastroenterology 2026;86(2):122-127
Although aspartate aminotransferase (AST) is a serum marker of hepatocellular damage in chronic hepatitis, it is difficult to interpret very high AST levels with concurrent low alanine aminotransferase (ALT) levels. Macro-AST is an immunoglobulin-AST complex that can present as aberrant high enzymatic activity without significant inflammation in the liver. Two patients with chronic hepatitis B presented with disproportionate AST elevations. Their plasma samples were precipitated with polyethylene glycol (PEG) and stored at 4°C for macro-AST determinations. In Case 1, PEG precipitation showed 100% removal of AST activity, and refrigerated storage resulted in a ~70% decline over seven days, confirming macro-AST. In Case 2, both tests showed minimal changes, suggesting that macro-AST was unlikely. The AST levels normalized after antiviral therapy, suggesting immune-active hepatitis as the probable cause, but the other contributing factors could not be completely excluded. The abrupt decrease in AST activity after PEG precipitation and during refrigeration storage suggests that relatively high AST values compared to ALT might be attributed to the presence of macro-AST.These non-invasive methods for detecting macroenzymes might help the patient avoid unnecessary further work-ups.
7.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.
8.Risk Factors and Clinical Characteristics of Graves’ Ophthalmopathy: a Retrospective Multicenter Study in Korea
Yoon Young CHO ; Hyunju PARK ; Jung HEO ; Jiyeon AHN ; Min Kyung LEE ; Jae Hyuk LEE ; Ju-Yuen LEE ; Yun Jin KIM ; Seo Young SOHN
International Journal of Thyroidology 2026;19(1):85-94
Background and Objectives:
Graves’ ophthalmopathy (GO) is an autoimmune inflammatory disorder that can adversely affect quality of life in patients with Graves’ disease (GD). The objective of this study was to characterize the clinical features of patients with GO and to identify risk factors associated with its development and the need for anti-inflammatory treatment.
Materials and Methods:
In this multicenter, retrospective observational study, 818 patients with GD were identified via electronic medical record review. Clinical characteristics were assessed, and logistic regression analyses were performed to identify risk factors for GO development and the need for anti-inflammatory treatment.
Results:
Among the 818 patients with GD, 135 (16.5%) developed GO, and 60 (7.3%) of these patients received anti-inflammatory treatment. GO was diagnosed at the time of GD diagnosis in 54.8% of cases, and proptosis and eyelid/orbital swelling were the common presenting features. In multivariable analysis, female sex (odds ratio [OR]: 1.75, confidence interval [CI]: 1.02-3.03), goiter (OR: 1.71, CI: 1.08-2.71), and smoking (ex-smokers: OR, 2.18; 95% CI: 1.02-4.65; current smokers: OR, 3.11; CI, 1.78-5.44) were independently associated with GO development, whereas diabetes (OR: 0.35, CI: 0.14-0.89) was inversely associated. Higher total cholesterol (OR: 1.31, CI: 1.01-1.04) and elevated thyrotropin-binding inhibitory immunoglobulin levels (OR: 1.07, CI: 1.02-1.11) were also significantly associated with the need for anti-inflammatory treatment.
Conclusion
This study delineated the clinical features of GO and identified risk factors for its development and the need for anti-inflammatory treatment in patients with GD, providing valuable information for the management of GO in Korean patients.
9.A Practical Immunohistochemistry-Based Model for Predicting Pathologic Complete Response in Estrogen Receptor-Strong Positive and HER2-Negative Breast Cancer
Su Min LEE ; Jeong Eon LEE ; Seok Jin NAM ; Seok Won KIM ; Jonghan YU ; Byung Joo CHAE ; Se Kyung LEE ; Jai Min RYU ; Eun Yoon CHO ; Hyunwoo LEE ; Woong Ki PARK
Journal of Breast Cancer 2026;29(2):128-140
Purpose:
While the benefit of neoadjuvant chemotherapy (NAC) has been established in human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancers, its effectiveness in achieving pathological complete response (pCR) and optimal patient selection in estrogen receptor (ER)-positive, HER2-negative breast cancers remain less clearly defined. This study aimed to identify immunohistochemistry (IHC)-based predictors of pCR and to develop a scoring model for ER-strong positive/HER2-negative breast cancer.
Methods:
Data from a prospective cohort were retrospectively analyzed. We included 522 patients with ER-strong positive/HER2-negative tumors who received NAC and surgery between 2008 and 2021. IHC markers including progesterone receptor (PR), Ki-67, epidermal growth factor receptor (EGFR), cytokeratin 5/6 (CK5/6), and p53 were evaluated to identify predictors of pCR. Independent predictors of pCR from multivariate logistic regression were used to develop a weighted 4-point model. Model performance was assessed using receiver operating characteristic analysis. The prognostic impact of pCR was evaluated using KaplanMeier and Cox regression analyses.
Results:
Independent predictors of pCR included PR-negative status, positivity for basallike markers (EGFR or CK5/6), and Ki-67 ≥ 50%. The scoring model demonstrated good discrimination for pCR (area under the curve = 0.754). pCR rates increased stepwise, with scores of 4.9% (low), 10.7% (intermediate), and 36.2% (high). In the high-score group, pCR was significantly associated with improved disease-free survival (hazard ratio [HR], 0.09; p = 0.023) and distant metastasis-free survival (HR, 0.11; p = 0.035), whereas no significant survival differences according to pCR status were observed in the low and intermediate score groups.
Conclusion
This IHC-based model predicts pCR and helps identify subgroups in which pCR is associated with meaningful survival benefit following NAC in ER-positive/HER2-negative breast cancers. High-scoring patients may benefit from NAC, while patients with low- or intermediatescores may be better managed with surgery and endocrine therapy. This model may support personalized treatment decisions regarding NAC.
10.Clinical Outcomes of Lobular Carcinoma In Situ: Risk of Invasive Cancer Development
Doyoun WOEN ; Ki Jo KIM ; Su Min LEE ; Seungah LEE ; Kawon OH ; Cho Eun LEE ; Seok Jin NAM ; Seok Won KIM ; Jeong Eon LEE ; Byung Joo CHAE ; Se Kyung LEE ; Jai Min RYU ; Woong Ki PARK ; Hyunwoo LEE ; Jonghan YU
Journal of Breast Cancer 2026;29(2):163-174
Purpose:
Lobular carcinoma In Situ (LCIS) is a noninvasive lesion associated with an increased risk of invasive cancer. Since its removal from the tumor, node, metastasis classification in the 8th edition of the American Joint Committee on Cancer (AJCC) guidelines, the clinical management of LCIS has shifted from surgery to surveillance. However, studies focusing on the risk and associated factors for invasive cancer development in pure LCIS without ductal carcinoma In Situ (DCIS) or invasive cancer remain limited.
Methods:
We retrospectively analyzed 106 patients diagnosed with pure LCIS between 2008 and 2018. This study evaluated the effect of tamoxifen use and histologic type on the development of invasive cancer.
Results:
All 106 patients underwent surgery, and nine (8.5%) developed invasive cancer over a median follow-up of 67.5 months. The incidence of invasive cancer was lower in the tamoxifen group (6.3%, n = 4) than in the non-tamoxifen group (11.9%, n = 5), although this difference was not statistically significant (p = 0.266). Pleomorphic LCIS had a significantly higher incidence of invasive cancer (30.0%, n = 3) than classic LCIS (6.3%, n = 6) (p = 0.045).Multivariable Cox regression analysis showed no significant difference in the risk of invasive cancer according to tamoxifen use (hazard ratio [HR], 2.031; 95% confidence interval [CI], 0.544–7.579; p = 0.292). However, pleomorphic LCIS showed a trend toward an increased risk of invasive cancer compared to classic LCIS (HR, 3.856; 95% CI, 0.922–16.126; p = 0.064).
Conclusion
Postoperative tamoxifen did not significantly lower invasive cancer development in patients with pure LCIS. Pleomorphic LCIS may carry a higher risk than classic LCIS. These findings require tailored follow-up and treatment strategies based on the histologic subtype of LCIS.

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