胸腺神经内分泌肿瘤与多发性内分泌肿瘤相关，仅被定义为类癌，不涉及大细胞神经内分泌癌（LCNEC）。我们报告了一例多发性内分泌肿瘤类型1患者的不典型类癌瘤（AC-h）病例，其有升高的有丝分裂计数，位于类癌和LCNEC之间的一种中间状态。一名27岁男性患者因前纵隔肿块接受手术治疗，诊断为胸腺LCNEC。15年后，同一部位出现了肿块，根据穿刺活检的病理结果和临床进展，确定为术后复发。该患者接受抗程序性死亡配体1抗体和含铂化疗治疗，疾病维持稳定状态达10个月。穿刺活检标本进行了下一代测序，发现MEN1基因突变，并经进一步检查确诊为多发性内分泌肿瘤类型1。15年前手术标本的复查显示其对应AC-h。虽然按照当前定义，胸腺AC-h属于胸腺LCNEC，但我们的数据表明在这些患者中应寻找多发性内分泌肿瘤。 ©2023作者。中国肺癌学会和John Wiley＆Sons Australia，Ltd.出版发行的《胸腺癌》。

Thymic neuroendocrine tumors associated with multiple endocrine neoplasia are only defined as carcinoid and are not associated with large-cell neuroendocrine carcinoma (LCNEC). We report the case of a multiple endocrine neoplasia type 1 patient with atypical carcinoid tumors with elevated mitotic counts (AC-h), an intermediate condition between carcinoid and LCNEC. A 27-year-old man underwent surgery for an anterior mediastinal mass and was diagnosed with thymic LCNEC. Fifteen years later, a mass appeared at the same site, which was determined to be a postoperative recurrence based on the pathological results of a needle biopsy and the clinical course. The patient's disease remained stable for 10 months on anti-programmed death-ligand 1 antibody and platinum-containing chemotherapy. The needle biopsy specimen was submitted for next-generation sequencing, which revealed a MEN1 gene mutation, and after further examination, a diagnosis of multiple endocrine neoplasia type 1 was made. A re-examination of the surgical specimen from 15 years prior showed that it corresponded to AC-h. Although thymic AC-h is classified as thymic LCNEC according to the current definition, our data suggests that a search for multiple endocrine neoplasia is warranted in such patients.© 2023 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.