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"Ji Yeon Byun"

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"Ji Yeon Byun"

Original article

[English]
Automated early detection of androgenetic alopecia using deep learning on trichoscopic images from a Korean cohort: a retrospective model development and validation study
Min Jung Suh, Sohyun Ahn, Ji Yeon Byun
Received June 23, 2025  Accepted July 16, 2025  Published online July 22, 2025  
DOI: https://doi.org/10.12771/emj.2025.00486    [Epub ahead of print]
Purpose
This study developed and validated a deep learning model for the automated early detection of androgenetic alopecia (AGA) using trichoscopic images, and evaluated the model’s diagnostic performance in a Korean clinical cohort.
Methods
We conducted a retrospective observational study using 318 trichoscopic scalp images labeled by board-certified dermatologists according to the Basic and Specific (BASP) system, collected at Ewha Womans University Medical Center between July 2018 and January 2024. The images were categorized as BASP 0 (no hair loss) or BASP 1–3 (early-stage hair loss). A ResNet-18 convolutional neural network, pretrained on ImageNet, was fine-tuned for binary classification. Internal validation was performed using stratified 5-fold cross-validation, and external validation was conducted through ensemble soft voting on a separate hold-out test set of 20 images. Model performance was measured by accuracy, precision, recall, F1-score, and area under the curve (AUC), with 95% confidence intervals (CIs) calculated for hold-out accuracy.
Results
Internal validation revealed robust model performance, with 4 out of 5 folds achieving an accuracy above 0.90 and an AUC above 0.93. In external validation on the hold-out test set, the ensemble model achieved an accuracy of 0.90 (95% CI, 0.77–1.03) and an AUC of 0.97, with perfect recall for early-stage hair loss. No missing data were present, and the model demonstrated stable convergence without requiring data augmentation.
Conclusion
This model demonstrated high accuracy and generalizability for detecting early-stage AGA from trichoscopic images, supporting its potential utility as a screening tool in clinical and teledermatology settings.
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Editorial

Original Article

[English]
No difference in inflammatory mediator expression between mast cell-rich and mast cell-poor rosacea lesions in Korean patients: a comparative study
Jin Ju Lee, Bo Ram Kwon, Min Young Lee, Ji Yeon Byun, Joo Young Roh, Hae Young Choi, You Won Choi
Ewha Med J 2025;48(1):e78.   Published online January 31, 2025
DOI: https://doi.org/10.12771/emj.2024.e78

Objectives: This study aimed to evaluate the correlation between mast cell (MC) density in rosacea-affected skin and the expression of key inflammatory mediators, including IL-6, TNF-α, and cathelicidin LL-37. By comparing lesions rich in MCs with those having fewer MCs, we sought to elucidate the role of MCs in the inflammatory mechanisms underlying rosacea pathogenesis.

Methods: Specimens were collected from 20 patients diagnosed with rosacea who attended the outpatient clinic between 2008 and 2013. Each specimen underwent staining using hematoxylin/eosin, Giemsa, IL-6, LL-37, and TNF-α for both histopathological and immunohistochemical analyses. The number of stained cells was counted across 10 randomly selected dermal layers at a magnification of ×400 using light microscopy. The results were categorized based on the number of MCs counted: more than 10 MCs were classified as MC-rich, and 10 or fewer MCs as MC-poor.

Results: Among the 20 patients (10 MC-rich and 10 MC-poor), the MC-rich group demonstrated significantly higher MC counts than the MC-poor group (P<0.001). However, there were no significant differences in the expression levels of IL-6, LL-37, or TNF-α between the two groups. Additionally, MC density did not show any significant associations with patient demographics, clinical characteristics, or systemic comorbidities.

Conclusion: Increased MC density was not associated with differences in IL-6, TNF-α, or LL-37 expression in rosacea lesions. These findings suggest that MC infiltration may not directly influence the inflammatory mediator profile in rosacea. Further research is required to identify distinctive pathological features or markers that can elucidate the mechanisms of rosacea.

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Case Report

[English]
Nontuberculous mycobacterial infection in a sporotricoid distribution in Korea: a case report
Jin Ju Lee, Yoon Jin Choi, Ji Yeon Byun, You Won Choi, Joo Young Roh, Hae Young Choi
Ewha Med J 2024;47(2):e29.   Published online April 30, 2024
DOI: https://doi.org/10.12771/emj.2024.e29

Nontuberculous mycobacterial infections, which are often acquired from environmental sources such as water and soil, exhibit a variety of cutaneous manifestations that frequently lead to misdiagnoses and delays in treatment. A 77-year-old woman presented with multiple skin lesions in a sporotricoid distribution on her right leg, which persisted despite standard antibiotic treatments. Based on the skin biopsy, revealing granulomatous inflammation with acid-fast bacilli, and PCR testing, a nontuberculous mycobacterial infection was diagnosed. Antimycobacterial drug combinations, including clarithromycin, isoniazid, and rifampicin for 4 months, complete the skin lesion's clearance. This case underscores the need for heightened suspicion and the use of appropriate diagnostic techniques, including tissue biopsies and molecular methods such as PCR.

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  • Clarithromycin

    Reactions Weekly.2024; 2014(1): 180.     CrossRef
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Images and Solution

[English]
Disseminated cutaneous gout: a rare manifestation of gout
Yoon Jin Choi, Ji Yeon Byun, You Won Choi, Hae Young Choi
Ewha Med J 2024;47(1):e9.   Published online January 31, 2024
DOI: https://doi.org/10.12771/emj.2024.e9
  • 234 View
  • 1 Download

Case Report

[English]
Pancreatic Panniculitis: A Case Report
Yoon Jin Choi, Min Young Lee, You Won Choi, Hae Young Choi, Ji Yeon Byun
Ewha Med J 2022;45(1):17-19.   Published online January 31, 2022
DOI: https://doi.org/10.12771/emj.2022.45.1.17

Pancreatic panniculitis is a rare skin complication in which subcutaneous fat necrosis occurs in association with pancreatic disorders, most commonly acute or chronic pancreatitis. Erythematous subcutaneous nodules develop on the legs and spontaneously ulcerate or exude an oily substance. A 32-year-old Korean female patient presented with a 2-week-history of tender nodules with erythematous crusts on her left shin. She had a history of alcoholic liver cirrhosis and, 5 weeks earlier, had been diagnosed with acute pancreatitis. The histopathologic findings from a skin biopsy were consistent with lobular panniculitis, without signs of vasculitis, and diffuse fat necrosis. Basophilic calcium deposits were present in the dermis and subcutaneous fat. These findings were suggestive of pancreatic panniculitis. The skin lesion had a chronic course corresponding to repeated exacerbations of the patient’s pancreatitis. Thus, in the differential diagnosis of subcutaneous nodules, clinicians should consider pancreatic panniculitis as a cutaneous manifestation of pancreatic disease.

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Images and Solution

[English]
Focal Acral Hyperkeratosis
Ji Yeon Byun, Rosa Kim, Min Young Lee, You Won Choi, Hae Young Choi
Ewha Med J 2021;44(4):144-145.   Published online October 31, 2021
DOI: https://doi.org/10.12771/emj.2021.44.4.144
  • 209 View
  • 1 Download
Editorial
[English]
The Beginning of Medical Education for Women in Korea: Boguyeogwan
Ji Yeon Byun, Ryung-Ah Lee
Ewha Med J 2015;38(2):59-62.   Published online July 29, 2015
DOI: https://doi.org/10.12771/emj.2015.38.2.59
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