Objective: This study aimed to evaluate the accuracy of predicting final adult height (FAH) in Korean girls with central precocious puberty (CPP) using artificial intelligence (AI)-derived bone age assessments integrated into the Bayley–Pinneau (BP) or Korean National Growth Chart (KGC) prediction models. Materials and Methods: This single-center, retrospective study included 122 Korean girls with CPP who received gonadotropinreleasing hormone agonist (GnRHa) treatment for at least two years between January 2000 and November 2022. We assessed bone age and predicted adult height at the initiation and completion of GnRHa treatment. We used three bone age assessment methods: human expert assessment based on the Greulich-Pyle (GP) atlas (Human-GP), AI-derived GP (AI-GP), and AI-weighted GP scoring (AI-GPw). We calculated predicted adult heights (PAHs) using both the BP and KGC models, generating 12 PAH estimates per patient (2 time points x 3 bone-age methods x 2 height-prediction models). We assessed prediction accuracy and agreement with FAH using linear regression analysis and Bland–Altman plots and performed multivariable analysis to identify significant predictors of FAH. Results: Human-GP, AI-GP, and AI-GPw demonstrated comparable overall performance in predicting FAH (R 2 : 0.470–0.646 and 0.691–0.822 for treatment initiation and completion, respectively). AI-GPw combined with BP yielded slightly better point estimates but showed no statistically significant differences. At both time points, the BP model demonstrated consistently narrower 95% limits of agreement (LoA) than the KGC model. Multivariable analysis identified AI-GPw-BP and height percentile score as significant predictors of FAH at both time points; mid-parental height was significant only at treatment initiation. Conclusion Human-GP, AI-GP, and AI-GPw demonstrated comparable accuracy in predicting FAH. The BP model demonstrated consistently narrower 95% LoA than did the KGC model. AI-GPw-BP was an independent predictor of FAH. These findings support the clinical utility of AI-derived bone age assessments for individualized FAH prediction in patients with CPP.

Although pediatric thyroid cancer is rare, it has characteristics distinct from those of adult thyroid cancer. Thyroid nodules in children present a higher risk of malignancy, more frequent lymph node and distant metastases, and distinct molecular profiles compared to adults. Despite a more aggressive initial presentation, the long-term prognosis for children is excellent, with paradoxically low mortality rates, even in patients with distant metastases. Therefore, it is questionable whether ultrasound-based risk-stratification systems primarily developed for adults can be directly applied to children. The 2021 Korean Thyroid Imaging Reporting and Data System (K-TIRADS) introduced pediatric-specific biopsy cut-offs and risk-adapted considerations, improving sensitivity, specificity, and overall accuracy. Nevertheless, challenges remain in achieving better diagnostic performance. Specific considerations must also be noted when evaluating pediatric thyroid nodules, such as the diffuse sclerosing subtype of papillary thyroid cancer and intrathyroidal ectopic thymus. Overdiagnosis and age-related heterogeneity further complicate risk assessment and management. Future guidelines could adopt stratified approaches based on patient age and sonographic mimickers, with additional integration of molecular profiling and artificial intelligence– assisted decision support. This review summarizes the current state of ultrasonographic evaluation of pediatric thyroid nodules, including the 2021 K-TIRADS, and discusses future refinements for pediatric-specific ultrasound risk-stratification systems.

Purpose: Malignant hepatocellular neoplasm, not otherwise specified (HCN-NOS) is a provisional diagnostic entity, characterised by intermediate or a combination of hepatoblastoma and pediatric hepatocellular carcinoma (p-HCC) features. We compared the characteristics of HCN-NOS with hepatoblastoma and p-HCC. Materials and Methods: The records of 148 pediatric patients diagnosed with hepatocellular malignancy after resection were retrieved from the institutional database. Clinical parameters and histopathology slides were reviewed to re-establish each patient’s diagnosis. Molecular analyses were conducted in 37 patients. Results: Patients were profiled as 21 (14.2%) with HCN-NOS, 109 (73.6%) with hepatoblastoma, and 18 (12.2%) with p-HCC. The median age was 8.6 years in HCN-NOS, 1.2 years in hepatoblastoma, and 7.9 years in p-HCC. Background liver disease was frequently observed in p-HCC (11/18, 61%) but infrequent in HCN-NOS (4/21, 19%) and hepatoblastoma (4/109, 3.7%). HCN-NOS presented with a more advanced PRETEXT stage (p=0.012), metastasis (p < 0.001), and lymphovascular invasion (p < 0.001) than hepatoblastoma and p-HCC. Patients with HCN-NOS received longer cycles of preoperative chemotherapy; however, they reported a lower decrease in serum alpha-fetoprotein and tumor size than hepatoblastoma (p=0.043, p=0.004, and p=0.044, respectively). HCN-NOS was an independent poor prognostic factor for event-free survival (hazard ratio, 4.968; 95% confidence interval, 2.004 to 12.32; p < 0.001). Conclusion The possibility of HCN-NOS should be considered in pediatric patients with liver cancer, especially those ≥ 5 years old with no background liver disease. Because HCN-NOS exhibits poor chemoresponsiveness and unfavourable postoperative prognosis, liver transplantation should be strongly considered.

Juvenile xanthogranuloma (JXG) is a rare histiocytic disorder primarily affecting children, typically presenting as self-limiting skin lesions. However, extracutaneous JXG (extra-JXG) or systemic JXG (sJXG) can involve various organs, including the central nervous system (CNS), leading to high morbidity and mortality, especially in cases of CNS involvement. Treatment approaches for CNS–JXG, including surgical resection, chemotherapy, and radiation therapy, lack consensus, with reports of relapsed or refractory cases being rare. Here, we present the case of a 2-year-old girl with refractory extra-JXG involving the CNS, characterized by multiple intracranial lesions.Initial chemotherapy with prednisolone and vinblastine showed no response, and second-line therapy, including cytarabine and vincristine combined with surgical resection, was also ineffective. However, a 6-cycle third-line chemotherapy regimen incorporating vincristine and carboplatin led to a positive response, with stable disease status, and normal growth and neurodevelopment observed. Our findings suggest that combined chemotherapy with carboplatin and vincristine is a feasible and well-tolerated treatment strategy for patients with CNS–JXG.

Objective: To determine the preventive effect of changing gadolinium-based contrast agents (GBCAs) to reduce the recurrence of GBCA-associated acute adverse drug reactions (ADRs). Materials and Methods: This retrospective, observational, single-center study—conducted between January 2016 and December 2021—included 238743 consecutive GBCA-enhanced MRI examinations. We focused on a subgroup of patients who experienced acute GBCA-associated ADRs during any of these examinations and subsequently underwent follow-up GBCAenhanced MRI examinations up until July 2023. The follow-up examinations involved either the same (non-change group) or different (change group) GBCAs compared to the ones that initially caused the acute ADR. Baseline participant characteristics, generic profile of the GBCAs, administration of premedication, history of prior ADR to iodinated contrast media, and symptoms of GBCA-associated acute ADRs were retrospectively analyzed. Multivariable logistic regression with generalized estimating equations and propensity score matching were used. Results: A total of 1042 instances of acute ADRs (0.44%; 95% confidence interval [CI]: 0.41%–0.46%) were reported. Threehundred and seventy-three patients underwent GBCA-enhanced MRI examinations after experiencing GBCA-associated acute ADRs within the study period; 31.9% (119/373) reexperienced acute ADRs at any of the follow-up examinations. The ADR recurrence was significantly lower in the GBCA change group than in the non-change group according to multivariable logistic regression (adjusted odds ratio [OR]: 0.35; 95% CI: 0.13–0.90; P = 0.03) and analysis with propensity score matching (14.3% [6/42] vs. 36.9% [31/84], respectively; OR: 0.32, 95% CI: 0.11–0.94; P = 0.04). A history of an ADR to iodinated contrast media (OR: 1.14, 95% CI: 0.68–1.90; P = 0.62) and premedication (adjusted OR: 2.09, 95% CI: 0.93–4.68; P = 0.07) were not significantly associated with GBCA-associated acute ADR recurrence. A separate analysis for recurrent allergic-like hypersensitivity reactions demonstrated similar results (adjusted OR: 0.20, 95% CI: 0.06–0.65; P < 0.01). Conclusion Changing GBCAs may reduce the risk of GBCA-associated acute ADR recurrence.