脊索瘤是一种罕见的恶性骨肿瘤，起源于脊索组织。常规治疗，如彻底切除和高剂量放射治疗，经常无法控制肿瘤，导致复发和再生。在这项研究中，对一名患有难治性常规脊索瘤的72岁男性患者头颅底部的肿瘤进行基因分析，发现其肿瘤突变负荷（TMB）高，MSH6和MLH1基因突变，这些基因在林奇综合征中发现。患者及其家族有很多癌症病史，并随后进行了遗传学检测，确诊为林奇综合征。这是第一个经遗传学证实为林奇综合征的脊索瘤报告。脊索瘤通常TMB很低，但这是一个不寻常的情况，因为TMB很高，免疫检查点抑制剂有效地控制了肿瘤。该案例为基于遗传分析确定脊索瘤免疫疗法适应症提供了基础。因此，将来的广泛基因分析将有助于分层治疗脊索瘤。 © 2023作者。

Chordoma is a rare malignant bone tumor arising from notochordal tissue. Conventional treatments, such as radical resection and high-dose irradiation, frequently fail to control the tumor, resulting in recurrence and re-growth. In this study, genetic analysis of the tumor in a 72-year-old male patient with refractory conventional chordoma of the skull base revealed a high tumor mutational burden (TMB) and mutations in the MSH6 and MLH1 genes, which are found in Lynch syndrome. The patient and his family had a dense cancer history, and subsequent germline genetic testing revealed Lynch syndrome. This is the first report of a chordoma that has been genetically proven to be Lynch syndrome. Chordomas usually have low TMB; however, this is an unusual case, because the TMB was high, and immune checkpoint inhibitors effectively controlled the tumor. This case provides a basis for determining the indications for immunotherapy of chordoma based on the genetic analysis. Therefore, further extensive genetic analysis in the future will help to stratify the treatment of chordoma.© 2023. The Author(s).