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What to Do for Atypia of Undetermined Significance in Pediatric Thyroid Nodules?
Zulal Ozdemir Uslu1, Nebiyye Genel2, Elif Tugce Tunca Kucukali1
1University of Health Sciences Türkiye, Ankara Dr. Sami Ulus Child Health and Diseases Training and Research Hospital, Clinic of Pediatric Endocrinology, Ankara, Türkiye
Insights
Pediatric thyroid nodules with atypia of undetermined significance (AUS) require careful management. Nuclear atypia in AUS cases indicates malignancy, suggesting lobectomy for these patients to avoid delayed diagnosis or unnecessary surgery.
Area of Science:
- Endocrinology
- Surgical Pathology
- Pediatric Oncology
Background:
- Management of pediatric thyroid nodules with atypia of undetermined significance (AUS) cytology differs between guidelines.
- American Thyroid Association (ATA) guidelines recommend surgery, while European Thyroid Association (ETA) guidelines suggest repeating fine-needle aspiration biopsy (FNAB).
- This discrepancy highlights the need for refined diagnostic markers and management strategies for pediatric AUS nodules.
Purpose of the Study:
- To identify specific markers of malignancy in pediatric thyroid nodules classified as AUS.
- To evaluate the effectiveness of current guidelines (ATA and ETA) in managing these cases.
- To propose an optimized management approach for pediatric AUS thyroid nodules based on cytopathological features.
Main Methods:
- Retrospective analysis of 20 pediatric patients with AUS cytology who underwent surgical resection.
- Re-evaluation of surgical specimens using the Bethesda 2023 classification system.
- Correlation of cytopathological features with histological diagnosis (benign vs. malignant).
Main Results:
- Histological diagnosis revealed 55% benign and 45% malignant nodules.
- Nuclear atypia was present in 70% of AUS cases, with 64.3% of these being malignant.
- Chromatin clearing, nuclear enlargement, and irregular margins were significantly associated with malignancy (p<0.05).
Conclusions:
- Lobectomy is recommended for pediatric AUS thyroid nodules exhibiting nuclear atypia to prevent diagnostic delays and overtreatment.
- Current guidelines may lead to delayed diagnosis (ETA) or unnecessary surgery (ATA) in a significant proportion of cases.
- Updating guidelines based on the Bethesda 2023 classification and cytopathological features like nuclear atypia is crucial.
Objective:
International guidelines recommend different approaches for the management of pediatric thyroid nodules with a finding of atypia of undetermined significance (AUS) on cytology. The American Thyroid Association (ATA) pediatric guidelines recommend surgery whereas the European Thyroid Association (ETA) guidelines recommend repeat fine-needle aspiration biopsy after six months. Our objective was to identify markers of malignancy in AUS cases and to discuss the management of pediatric AUS nodules.
Methods:
Specimens from pediatric patients who underwent surgery due to AUS cytology were re-evaluated and subcategorized according to the 2023 Bethesda classification.
Results:
Of the 20 cases included, 11 (55%) were histologically benign, while 9 (45%) were malignant. On the subcategorization of AUS, nuclear atypia was present in 14 patients (70%), and other atypia in 6 patients (30%). Of the cases with nuclear atypia, 64.3% were malignant (n=9), whereas no malignancy was detected in cases with other atypia (p=0.012). Among the cytopathological features, chromatin clearing, nuclear enlargement, and irregular margins were significantly associated with malignancy (p=0.035, p=0.003, and p=0.012, respectively). Adhering to ETA recommendations would delay diagnosis by at least 6 months in 45% of our malignant cases. Conversely, performing lobectomy according to ATA recommendations may lead to unnecessary surgery in 55% of our cases.
Conclusion:
Based on our findings, lobectomy appears to be a more appropriate approach in AUS cases but only when nuclear atypia is present, to avoid diagnostic delay and unnecessary surgery. Guidelines should be updated according to the latest Bethesda classification.
