甲舌管囊肿（Thyroglossal duct cyst, TDC）占所有先天性颈部肿块的约70％，其中多达1％含有甲状腺组织恶性肿瘤。术前TDC癌与良性肿瘤的临床表现通常难以区分，鉴别诊断具有挑战性。我们报道了一个罕见的青少年合并甲状腺癌的TDC癌例。病例报告：一名16岁的白种女性，除颈部逐渐扩大的无痛肿块外，身体健康。体格检查发现颈前中线甲状骨下前下区域有界限清晰、中等硬度、有触痛的肿块。影像学结果提示最可能的诊断为TDC。患者在全身麻醉下接受Sistrunk手术。组织病理学结果显示TDC中存在BRAFV600E阳性的乳头状甲状腺癌（PTC）。甲状腺及颈部超声显示VI级淋巴结存在高度可疑的恶性特征，但细针穿刺细胞学（FNAC）未能证实。患者在全身麻醉下进行了全甲状腺切除和中央区淋巴结颈部清扫。组织病理学结果显示甲状腺实质内存在PTC灶，并有3个淋巴结被PTC侵犯。患者接受了辅助性放射性碘消融（RAI）治疗，并密切随访。TDC癌并发甲状腺癌在年轻患者中很少见。术前诊断具有挑战性，因为年轻患者颈部肿块的绝大多数为良性肿瘤，而大多数恶性肿瘤缺乏特异性临床特征。由于其常为囊性特征，FNAC的诊断准确性被认为不令人满意。最终诊断基于组织病理学结果。临床医生应高度怀疑合并甲状腺恶性肿瘤的可能性。尽管外科切除肿瘤被视为常规治疗，但TDC癌的治疗应由多学科团队个体化组合进行。版权所有 © 2023 Kleanthi Mylopotamitaki et al.

Thyroglossal duct cysts (TDC) represent approximately 70% of all congenital neck masses, and up to 1% of them contain thyroid tissue malignancies. Clinical presentation of TDC carcinomas is usually indistinguishable from benign tumors preoperatively, and differential diagnosis can be challenging. We present a rare case of TDC carcinoma concurrent with thyroid cancer in an adolescent. Case Presentation. A 16-year-old Caucasian female, otherwise healthy, was referred with a painless, gradually expanding lump on the neck. Physical examination revealed a well-circumscribed, moderately hard, tender mass of the anterior neck midline anteroinferior to the hyoid bone. Imaging findings suggested TDC as the most likely diagnosis. The patient had a Sistrunk procedure under general anesthesia. Histopathological findings diagnosed a BRAFV600E-positive papillary thyroid carcinoma (PTC) in a TDC. A thyroid gland and neck ultrasound revealed a highly suspicious finding for malignancy right level VI lymph node, which was not confirmed by fine needle aspiration cytology (FNAC). Under general anesthesia, total thyroidectomy and central compartment lymph node neck dissection were performed. Histopathological findings revealed a thyroid parenchymal locus of PTC, as well as three lymph nodes infiltrated by PTC. The patient received adjuvant radioactive iodine ablation (RAI) therapy and is closely followed.TDC carcinomas in conjunction with thyroid carcinomas in young patients are rare. Preoperative diagnosis can be challenging, as the vast majority of neck masses in young patients are benign in nature, and most malignant tumors lack specific clinical features. The diagnostic accuracy of FNAC is considered unsatisfactory due to its frequently cystic nature. Definitive diagnosis is based on histopathological findings. Clinicians should maintain a high level of suspicion for coexisting thyroid malignancies. Although surgical extirpation of the malignancy is considered standard of care, the treatment of TDC cancer should always be individualized by a multidisciplinary team.Copyright © 2023 Kleanthi Mylopotamitaki et al.