Based on the concept of the adenoma‐carcinoma sequence, most colorectal cancers are considered to arise from conventional adenomas. However, recent studies suggested that a subset of colorectal cancers develop through the serrated neoplastic pathway. It has also been documented that serrated polyps can rapidly transform into invasive cancers even when they are small in size. We now describe a case of a sessile serrated adenoma/polyp which had been followed up for 4 years but eventually showed rapid transformation into an advanced cancer accompanied by a remarkable morphological change within only 13 months. Retrospective genetic and epigenetic analyses showed microsatellite instability, CpG island methylator phenotype‐positive, and BRAF mutation in the lesion, suggesting the tumor had developed through the serrated neoplastic pathway. This case may provide valuable information about the natural history of sessile serrated adenoma/polyps which eventually progress to advanced cancers.

中文翻译：

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无蒂锯齿状息肉/腺瘤 (SSA/P) 在最后 13 个月内显示出快速恶变 – 病例报告 –

根据腺瘤-癌序列的概念，大多数结直肠癌被认为起源于常规腺瘤。然而，最近的研究表明，一部分结直肠癌是通过锯齿状肿瘤途径发展而来的。也有文献记载，锯齿状息肉即使体积很小，也能迅速转变为浸润性癌症。我们现在描述一例无蒂锯齿状腺瘤/息肉病例，该病例已随访 4 年，但最终在仅 13 个月内迅速转变为晚期癌症并伴有显着的形态变化。回顾性遗传和表观遗传分析显示微卫星不稳定性、CpG 岛甲基化表型阳性和病变中的 BRAF 突变，表明肿瘤是通过锯齿状肿瘤途径发展的。