INTRODUCTION Muir-Torre syndrome, presenting with cutaneous tumors and visceral malignancies, is a variant of Lynch syndrome. The development of immune checkpoint inhibitors provided novel effective treatment options for metastatic colorectal cancer patients with microsatellite instability and deficient mismatch repair. However, the use of immune checkpoint inhibitors in neoadjuvant and adjuvant settings for patients with locally advanced colorectal cancer remains undefined because of limited follow-ups in current studies. CASE PRESENTATION In the present study, we reported a 33-year-old Muri-Torre syndrome patient with stage ⅢC (c.T4N2M0) colorectal cancer and keratoacanthoma. Microsatellite instability / deficient mismatch repair, high tumor mutation burden, and MSH2 germline mutation were identified by next-generation sequencing. Pembrolizumab monotherapy was used as neoadjuvant treatment and the patient achieved a major pathological response. After surgical resection, pembrolizumab was continuously used in an adjuvant setting for 12 months. The patient remained disease-free with a durable disease-free survival for 44 months. To our knowledge, this is the first and longest follow-up study reporting pembrolizumab as a single-agent neoadjuvant therapy for locally advanced colon cancer. CONCLUSIONS The results demonstrate promising performance in neoadjuvant and adjuvant settings. Further studies are needed to confirm its potential usefulness as an outcome measure in clinical practice.

中文翻译：

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一名患有 Muir-Torre 综合征的局部晚期结肠癌患者对新辅助和辅助免疫治疗获得了持久的反应。

引言 Muir-Torre 综合征表现为皮肤肿瘤和内脏恶性肿瘤，是 Lynch 综合征的一种变体。免疫检查点抑制剂的开发为微卫星不稳定性和错配修复缺陷的转​​移性结直肠癌患者提供了新的有效治疗选择。然而，由于当前研究的随访有限，免疫检查点抑制剂在局部晚期结直肠癌患者的新辅助和辅助治疗中的使用仍不确定。病例介绍在本研究中，我们报告了一名 33 岁的 Muri-Torre 综合征患者，患有 ⅢC 期（c.T4N2M0）结直肠癌和角化棘皮瘤。通过新一代测序鉴定出微卫星不稳定性/错配修复缺陷、高肿瘤突变负荷和 MSH2 种系突变。使用派姆单抗单药治疗作为新辅助治疗，患者取得了主要的病理缓解。手术切除后，派姆单抗在辅助治疗中持续使用 12 个月。患者保持无病状态，并持续无病生存 44 个月。据我们所知，这是第一个也是最长的随访研究报告派姆单抗作为局部晚期结肠癌的单药新辅助疗法。结论 结果表明在新辅助和辅助设置中具有良好的性能。需要进一步的研究来证实其作为临床实践结果衡量指标的潜在用途。