Superficially serrated adenoma: a proposal for a novel subtype of colorectal serrated lesion
Superficially serrated adenoma: a proposal for a novel subtype of colorectal serrated lesion
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DOI：
10.1038/s41379-018-0069-8
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发表时间：
2018-10-01
期刊：
影响因子：
7.5
通讯作者：
Sekine, Shigeki
中科院分区：
文献类型：
--
作者：
Hashimoto, Taiki;Tanaka, Yusaku;Sekine, Shigeki
我们描述了一系列以混合的腺瘤和锯齿状特征为特征的大肠息肉，这里称为表面锯齿状腺瘤。浅锯齿状腺瘤20例，女性11例，男性9例，年龄62~87岁。大多数病变在内窥镜下表现为小的无柄息肉，但较大的病变为斑块状(2-20 mm；中位数，5 mm)。18个病变(90%)位于乙状结肠或直肠。它们主要由笔直的腺瘤组成，但仅限于浅层呈锯齿状。免疫组织化学显示CK20在上层有表达。增殖细胞由Ki-67的表达决定，定位于中下层。遗传分析在19个病变中发现了KRAS突变，在一个病变中发现了BRAF突变。此外，在18个病灶中观察到RSPO融合和/或过表达，在其余两个病灶中观察到截短的APC突变。与WNT途径基因改变的存在相一致，所有表面锯齿状的腺瘤都表现为局限性或弥漫性的核β-连环素积聚。由于并发KRAS突变和RSPO融合在传统锯齿状腺瘤中很常见，我们回顾了129个传统锯齿状腺瘤，发现15个病变(12%)与表面锯齿状腺瘤成分相关。值得注意的是，除了一个与表面锯齿状腺瘤相关的传统锯齿状腺瘤外，所有这些肿瘤都同时表现出KRAS突变和RSPO融合/过度表达。本研究提示，表面锯齿状腺瘤是一种形态和分子上不同的大肠锯齿状息肉，在组织学上与传统的锯齿状腺瘤有关。
We describe a series of colorectal polyps characterized by mixed adenomatous and serrated features, herein referred to as superficially serrated adenomas. Twenty superficially serrated adenomas were obtained from 11 female and 9 male patients aged 62-87 years. Most lesions endoscopically appeared as small sessile polyps, but larger lesions were plaque-like (2-20 mm; median, 5 mm). Eighteen lesions (90%) were located in the sigmoid colon or rectum. They consisted primarily of straight, adenomatous glands but showed serration confined to the superficial layer. Immunohistochemistry revealed CK20 expression in the upper layer. Proliferating cells, determined by their expression of Ki-67, were localized to the middle to bottom layers. Genetic analyses identified KRAS mutations in 19 lesions and a BRAF mutation in one lesion. Furthermore, RSPO fusions and/or overexpression were observed in 18 lesions and truncating APC mutations were observed in the two remaining lesions. Consistent with the presence of WNT pathway gene alterations, all superficially serrated adenomas showed focal or diffuse nuclear beta-catenin accumulation. Since concurrent KRAS mutations and RSPO fusions are reportedly common in traditional serrated adenomas, we reviewed 129 traditional serrated adenomas and found 15 lesions (12%) that were associated with superficially serrated adenoma components. Remarkably, all but one superficially serrated adenoma-associated traditional serrated adenoma exhibited concurrent KRAS mutations and RSPO fusions/overexpression. The present study suggests that superficially serrated adenoma is a morphologically and molecularly distinct type of colorectal serrated polyp that is histogenetically related to traditional serrated adenoma.