Zhang Sijia, Wu Lu, Li Zhenyu, Li Qianwen, Zong Yan, Zhu Kuikui, Chen Leichong, Qin Haifeng, Meng Rui
Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 156 Wujiadun, Jianghan District, Wuhan, Hubei Province, 430022, China.
Department of Pulmonary Neoplasm Internal Medicine, Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China.
Open Life Sci. 2023 May 18;18(1):20220600. doi: 10.1515/biol-2022-0600. eCollection 2023.
Thymomas and thymic carcinomas are rare and primary tumors of the mediastinum which is derived from the thymic epithelium. Thymomas are the most common primary anterior mediastinal tumor, while ectopic thymomas are rarer. Mutational profiles of ectopic thymomas may help expand our understanding of the occurrence and treatment options of these tumors. In this report, we sought to elucidate the mutational profiles of two ectopic thymoma nodules to gain deeper understanding of the molecular genetic information of this rare tumor and to provide guidance treatment options. We presented a case of 62-year-old male patient with a postoperative pathological diagnosis of type A mediastinal thymoma and ectopic pulmonary thymoma. After mediastinal lesion resection and thoracoscopic lung wedge resection, the mediastinal thymoma was completely removed, and the patient recovered from the surgery and no recurrence was found by examination until now. Whole exome sequencing was performed on both mediastinal thymoma and ectopic pulmonary thymoma tissue samples of the patient and clonal evolution analysis were further conducted to analyze the genetic characteristics. We identified eight gene mutations that were co-mutated in both lesions. Consistent with a previous exome sequencing analysis of thymic epithelial tumor, was also observed in both mediastinal lesion and lung lesion tissues. We also evaluated the intratumor heterogeneity of non-silent mutations. The results showed that the mediastinal lesion tissue has higher degree of heterogeneity and the lung lesion tissue has relatively low amount of variant heterogeneity in the detected variants. Through pathology and genomics sequencing detection, we initially revealed the genetic differences between mediastinal thymoma and ectopic thymoma, and clonal evolution analysis showed that these two lesions originated from multi-ancestral regions.
胸腺瘤和胸腺癌是源自胸腺上皮的罕见纵隔原发性肿瘤。胸腺瘤是最常见的原发性前纵隔肿瘤，而异位胸腺瘤则较为罕见。异位胸腺瘤的突变谱可能有助于拓展我们对这些肿瘤发生及治疗选择的理解。在本报告中，我们试图阐明两个异位胸腺瘤结节的突变谱，以更深入了解这种罕见肿瘤的分子遗传信息，并为治疗选择提供指导。我们报告了一例62岁男性患者，术后病理诊断为A型纵隔胸腺瘤和异位肺胸腺瘤。在进行纵隔病变切除和胸腔镜肺楔形切除术后，纵隔胸腺瘤被完全切除，患者术后恢复，至今检查未发现复发。对该患者的纵隔胸腺瘤和异位肺胸腺瘤组织样本进行了全外显子组测序，并进一步进行克隆进化分析以分析遗传特征。我们在两个病变中鉴定出八个共同突变的基因突变。与先前对胸腺上皮肿瘤的外显子组测序分析一致，在纵隔病变和肺病变组织中也均观察到[此处原文缺失相关内容]。我们还评估了非沉默突变的肿瘤内异质性。结果显示，在检测到的变异中，纵隔病变组织具有更高程度的异质性，而肺病变组织的变异异质性相对较低。通过病理学和基因组测序检测，我们初步揭示了纵隔胸腺瘤和异位胸腺瘤之间的遗传差异，克隆进化分析表明这两个病变起源于多个祖先区域。
