Follicular-patterned tumors of the thyroid in the adult population frequently harbor RAS mutations or PAX8-PPARG rearrangement, but little is known about molecular profiles in the pediatric patients with thyroid tumors, which is rare. To identify the molecular profile of pediatric follicular-patterned tumors, we enrolled 41 pediatric patients with follicular-patterned tumors from two institutions. We did next-generation sequencing using a mutation panel targeting 49 thyroid-tumor-related genes and a fusion panel targeting 88 types of thyroid-related gene fusions. We identified nonsynonymous mutations in at least one target gene in most of the tumors (28/41, 68%). Somatic DICER1 mutations (22%, n = 9) were the most common genetic alteration, followed by mutations of NRAS (15%), FGFR3 (15%), PTEN (12%), and STK11 (10%). Infrequent genetic alterations (≤ 5% of all cases) included mutations of HRAS, APC, TSHR, CTNNB1, TP53, EIF1AX, FGFR4, GNAS, RET, and SOS1, and gene fusion of THADA-IGF2BP3. DICER1 and RAS mutations were mutually exclusive. No patients had tumors related to the DICER1 syndrome or the Cowden syndrome. There was no significant difference in total mutation burden or distribution between follicular adenoma and follicular carcinoma. In the literature, the DICER1 mutation has been reported in 20 to 53% of pediatric patients with follicular-patterned tumors. In conclusion, our study reinforces the role of the DICER1 mutation in the development of pediatric thyroid tumors. Gene fusions rarely occur in pediatric follicular-patterned tumors. Mutation or gene fusion alone could not distinguish benign from malignant follicular-patterned tumors in pediatric patients.

成人甲状腺滤泡型肿瘤经常携带RAS突变或PAX8-PPARG重排，但对儿童甲状腺肿瘤患者的分子谱知之甚少，这种情况很少见。为了确定儿科滤泡型肿瘤的分子谱，我们从两家机构招募了 41 名患有滤泡型肿瘤的儿科患者。我们使用针对 49 个甲状腺肿瘤相关基因的突变组和针对 88 种甲状腺相关基因融合的融合组进行了下一代测序。我们在大多数肿瘤中发现了至少一个靶基因的非同义突变（28/41，68%）。体细胞DICER1突变（22%，n = 9) 是最常见的遗传改变，其次是NRAS (15%)、FGFR3 (15%)、PTEN (12%) 和STK11 (10%) 的突变。不常见的基因改变（≤5%）包括HRAS、APC、TSHR、CTNNB1、TP53、EIF1AX、FGFR4、GNAS、RET和SOS1的突变，以及THADA - IGF2BP3的基因融合。DICER1和RAS突变是相互排斥的。没有患者患有与 DICER1 综合征或 Cowden 综合征相关的肿瘤。滤泡性腺瘤和滤泡性癌之间的总突变负荷或分布没有显着差异。在文献中，20% 至 53% 的滤泡型肿瘤儿科患者报告了DICER1突变。总之，我们的研究加强了DICER1突变在小儿甲状腺肿瘤发展中的作用。基因融合很少发生在小儿滤泡型肿瘤中。仅靠突变或基因融合无法区分儿科患者的良性和恶性滤泡型肿瘤。