Department of Gastroenterology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Department of Human Pathology, Juntendo University School of Medicine, Tokyo, Japan.
Surg Endosc. 2021 Aug;35(8):4528-4538. doi: 10.1007/s00464-020-07967-w. Epub 2020 Sep 9.
Sessile serrated lesion (SSL) is a colorectal polyp that has malignant potential. However, the dysplastic components within an SSL can be difficult to diagnose with conventional endoscopy, because most SSLs with dysplasia/carcinoma have subtle mucosal features. Many studies have indicated that narrow-band imaging (NBI) observations of colorectal polyps are very useful, accurate predictors of histology. We aimed to verify the usefulness of the Japan NBI Expert Team (JNET) classification system for the diagnosis of SSLs with dysplasia/carcinoma.
We examined 709 endoscopically or surgically resected lesions that were pathologically diagnosed as SSL, including 647 with no dysplasia, 37 with low-grade dysplasia, 15 with high-grade dysplasia, and 10 with submucosal invasive carcinoma. We retrospectively evaluated their clinicopathologic characteristics and conventional endoscopic and magnifying NBI endoscopic findings using the JNET system.
Cases in all groups were more frequently located in the proximal colon. Submucosal invasive carcinomas were significantly larger than no dysplasia and low-grade dysplasia lesions. Almost all studied lesions (96.3%) were covered with a mucus cap. Five hundred and eighty (81.8%) lesions exhibited dark spots inside the crypts, which are NBI findings' characteristic of SSL. As for the JNET classification of magnifying NBI endoscopic findings, all 709 lesions showed Type 1. Six hundred and eighteen (95.5%) SSLs with no dysplasia lesions exhibited Type 1 only, whereas 52 (83.9%) SSLs with dysplasia/carcinoma had a combination of Type 1 and Type 2A, 2B, or 3, corresponding to SSL and dysplasia/carcinoma, respectively. The JNET classification had high sensitivity (83.9%), specificity (95.5%), and overall diagnostic accuracy (94.5%) for diagnosing SSLs with dysplasia/carcinoma.
Use of magnifying NBI endoscopy with the JNET classification might be useful for diagnosing SSLs with dysplasia/carcinoma. This increased awareness may also improve the recognition of SSLs with dysplasia/carcinoma.
无蒂锯齿状病变（SSL）是一种具有恶性潜能的结直肠息肉。然而，由于大多数伴有异型增生/癌的 SSL 具有细微的黏膜特征，因此常规内镜下对其异型增生成分的诊断较为困难。许多研究表明，窄带成像（NBI）观察结直肠息肉非常有用，是组织学的准确预测指标。我们旨在验证日本 NBI 专家团队（JNET）分类系统对诊断伴有异型增生/癌的 SSL 的有效性。
我们检查了 709 例经内镜或手术切除的病理诊断为 SSL 的病变，其中 647 例无异型增生，37 例低级别异型增生，15 例高级别异型增生，10 例黏膜下浸润性癌。我们使用 JNET 系统回顾性评估了这些病变的临床病理特征以及常规内镜和放大 NBI 内镜下表现。
所有组别的病例均更常位于近端结肠。黏膜下浸润性癌显著大于无异型增生和低级别异型增生病变。几乎所有研究的病变（96.3%）均被黏液帽覆盖。580 例（81.8%）病变的隐窝内可见黑色斑点，这是 SSL 的 NBI 特征性表现。对于放大 NBI 内镜下 JNET 分类，709 例病变均表现为 1 型。618 例（95.5%）无异型增生的 SSL 病变仅表现为 1 型，而 52 例（83.9%）伴有异型增生/癌的 SSL 病变则为 1 型和 2A、2B 或 3 型的组合，分别对应于 SSL 和异型增生/癌。JNET 分类对诊断伴有异型增生/癌的 SSL 具有较高的敏感性（83.9%）、特异性（95.5%）和总体诊断准确性（94.5%）。
使用 JNET 分类的放大 NBI 内镜检查可能有助于诊断伴有异型增生/癌的 SSL。这种认识的提高也可能提高对伴有异型增生/癌的 SSL 的识别能力。
