Lynch syndrome is an autosomal dominant disease characterized by a germline mutation in mismatch repair genes resulting in microsatellite instability and high mutational burden.

Lynch syndrome is responsible for 2% to 4% of all colorectal cancer cases and is associated with an up to 80% increase in the lifetime risk of colorectal cancer.

Thanks to better screening and earlier diagnosis, prognosis of patients with Lynch syndrome is improving_, but also leading to the emergence of unusual presentations and histopathological variants.

Squamous cell colorectal carcinomas are extremely rare with only one previously reported case in association with Lynch syndrome.

There is lack of data regarding the best management for squamous cell cancers in the colon and rectum and treatment has been historically based on that for adenocarcinomas.

Evidence supporting the use of immunotherapy in mismatch repair deficient tumors is rapidly growing and has led to the first FDA molecular guided, tissue/site agnostic approval.

It can be argued that the management approach for patients with Lynch syndrome should be based on genetic and molecular factors regardless of tumor site or histology.

Lynch 综合征是一种常染色体显性遗传疾病，其特征是错配修复基因的种系突变导致微卫星不稳定和高突变负担。

林奇综合征占所有结直肠癌病例的 2% 至 4%，并且与结直肠癌的终生风险增加高达 80% 相关。

由于更好的筛查和早期诊断，Lynch 综合征患者的预后正在改善_，但也导致出现异常表现和组织病理学变异。

鳞状细胞结直肠癌极为罕见，之前仅报道过一例与 Lynch 综合征相关的病例。

缺乏关于结肠和直肠鳞状细胞癌最佳治疗的数据，并且治疗历来基于腺癌。

支持在错配修复缺陷肿瘤中使用免疫疗法的证据正在迅速增长，并导致 FDA 首次分子指导、组织/部位不可知的批准​​。

可以说，林奇综合征患者的管理方法应基于遗传和分子因素，而不考虑肿瘤部位或组织学。