甲状腺的碰撞和复合癌极为罕见，其临床和生物学特征了解甚少。第一例病例是一名41岁的女性患者，患有右侧甲状腺结节。病理诊断为乳头状甲状腺癌（PTC）和髓样甲状腺癌复合癌。手术治疗为右侧甲状腺切除+左侧部分甲状腺切除+右侧中央颈淋巴结清扫。第二例病例是一名60岁的女性，双侧甲状腺结节。进行了全甲状腺切除，病理诊断为碰撞型甲状腺癌，涉及左侧滤泡性甲状腺癌和右侧PTC。甲状腺碰撞和复合癌的临床、组织学和基因变化描述不足。由于具有不同的生物入侵特征，目前对其理想治疗和预后尚不清楚，需要个体化治疗。建议在复合癌中，根据最严重的肿瘤评估和治疗每个癌症。碰撞型癌应视为两个独立的同步原发肿瘤进行处理。对于甲状腺的碰撞和复合癌，治疗后的随访应全面进行。© 2023. BioMed Central Ltd., Springer Nature的一部分。

Collision and composite carcinomas of the thyroid are extremely rare, and their clinical and biological characteristics are poorly understood.The first case was a 41-year-old female patient with a right thyroid nodule. Pathological diagnosis was papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma composite carcinoma. Surgical treatment was right thyroid lobectomy + left partial thyroidectomy + right central neck lymph node dissection. The second case was a 60-year-old female with bilateral thyroid nodules. Total thyroidectomy was performed, and the pathological diagnosis was thyroid collision carcinoma involving follicular thyroid carcinoma on the left side and PTC on the right side. The clinical, histological and gene changes of collision and composite carcinomas of the thyroid are poorly described. With different biological invasion characteristics, the ideal treatment and the prognosis is currently unknown and individualized treatment is necessary.It is recommended that in composite carcinoma, each cancer is evaluated and treated according to the most severe tumor. Collision carcinoma should be treated as two separate synchronous primary tumors. For both collision and composite carcinomas of the thyroid, the follow-up after treatment should be extensive.© 2023. BioMed Central Ltd., part of Springer Nature.