Supplementary Material for: Exploring the Heterogeneity of Pediatric Neuroendocrine Tumors: Single-Center Experience

Introduction: Neuroendocrine tumors (NETs) are rare, slow-growing tumors with distinct clinical manifestations that can be challenging to diagnose and treat, particularly in children. This retrospective study aimed to improve diagnosis and treatment of NETs by evaluating their clinical course, hormonal activity, and long-term effects in children.
Methods: A retrospective study was conducted on 26 pediatric patients diagnosed with NETs between 2000 and 2024. The cohort included patients with pheochromocytoma and paraganglioma (PPGL), gastroenteropancreatic neuroendocrine tumors (GEP-NETs) medullary thyroid carcinoma (MTC), C cell hyperplasia. The data included demographic, clinical, laboratory, and imaging results.
Results: The study cohort included 26 patients (57.6% male). The median age for diagnosis of NETs was 8.8 (range: 1.0–16.6) years. Among the NETs, 15.4% were GEP-NETs, 15.4% were PPGL, 15.4% were C cell hyperplasia and 53.8% were MTC. The median follow-up was 5 (range: 1–14) years. Among the patients in the study cohort, only one patient died due to MTC. Genetic analysis revealed mutations in the RET gene in 69.2% of patients, mutations in the VHL gene in 3.8%, and no mutations in 3.8%. 23% of the patients did not undergo genetic testing.
Conclusion: Early diagnosis, genetic screening, and long-term follow-up are crucial in managing pediatric NETs to reduce morbidity and mortality. Genetic testing is essential for identifying comorbidities and screening family members at risk.

Introduction: 神经内分泌肿瘤（Neuroendocrine tumors, NETs）是一类罕见的缓慢生长肿瘤，具有独特的临床表现，诊断与治疗难度较大，儿童患者尤其如此。本回顾性研究通过评估儿童NETs的临床病程、激素活性及长期影响，旨在优化其诊断与治疗策略。
Methods: 本研究回顾性分析了2000年至2024年间确诊为NETs的26例儿童患者。研究队列包括嗜铬细胞瘤与副神经节瘤（pheochromocytoma and paraganglioma, PPGL）、胃肠胰神经内分泌肿瘤（gastroenteropancreatic neuroendocrine tumors, GEP-NETs）、甲状腺髓样癌（medullary thyroid carcinoma, MTC）及C细胞增生（C cell hyperplasia）患者。收集的数据涵盖人口统计学特征、临床资料、实验室检查及影像学结果。
Results: 研究队列共纳入26例患者（男性占57.6%）。NETs确诊的中位年龄为8.8岁（范围：1.0–16.6岁）。在所有NETs中，胃肠胰神经内分泌肿瘤（GEP-NETs）、嗜铬细胞瘤与副神经节瘤（PPGL）、C细胞增生各占15.4%，甲状腺髓样癌（MTC）占53.8%。中位随访时间为5年（范围：1–14年）。队列中仅1例患者因MTC死亡。基因分析显示，69.2%的患者存在RET基因（RET gene）突变，3.8%存在VHL基因（VHL gene）突变，另有3.8%无突变；23%的患者未接受基因检测。
Conclusion: 早期诊断、基因筛查及长期随访对于儿童NETs的管理至关重要，可降低发病率与死亡率。基因检测在识别合并症及筛查高危家庭成员方面具有重要意义。