The significance of serrated epithelial change (SEC), defined as endoscopically invisible hyperplastic polyp (HP)-like mucosal change identified in patients with inflammatory bowel disease (IBD), remains unclear. Although some studies reported an increased risk of synchronous and/or metachronous colorectal neoplasia in patients with SEC, including advanced neoplasia (high-grade dysplasia or colorectal cancer), the development of SEC is not significantly associated with increased colonic inflammation. This contrasts with the reported positive correlation between increased colonic inflammation and the risk of colorectal neoplasia in ulcerative colitis, arguing against the notion that SEC may represent a form of dysplasia. As such, this study aimed to characterize the features of synchronous and metachronous dysplasia detected in patients with SEC to identify factors contributing to the increased risk of colorectal neoplasia, including advanced neoplasia, observed in a subset of these patients. Clinicopathologic features of 46 IBD patients with SEC (n=109) and synchronous and/or metachronous dysplasia (n=153) were analyzed. All dysplastic lesions were subtyped as either conventional or nonconventional dysplasia. As controls, 45 IBD patients with endoscopically visible or polypoid HP (n=75) and synchronous and/or metachronous dysplasia (n=87) were analyzed. The SEC group included 28 (61%) men and 18 (39%) women with a mean age of 58 years and a long history of IBD (mean duration: 23 years). The majority of patients (n=34; 74%) had ulcerative colitis, and 12 (26%) had Crohn's disease. Thirty-nine (85%) patients had a history of pancolitis, and 2 (4%) had concomitant primary sclerosing cholangitis. Twenty-seven (59%) patients had multifocal SEC. SEC was predominantly found in the left colon (n=52; 48%) and rectum (n=34; 31%). Dysplasia in the SEC group was often endoscopically invisible or flat (n=42; 27%) and demonstrated nonconventional dysplastic features (n=49; 32%). Six nonconventional subtypes were identified in the SEC group, including 17 (11%) dysplasia with increased Paneth cell differentiation, 12 (8%) hypermucinous dysplasia, 8 (5%) crypt cell dysplasia, 7 (5%) goblet cell deficient dysplasia, 3 (2%) sessile serrated lesion-like dysplasia, and 2 (1%) traditional serrated adenoma-like dysplasia. Advanced neoplasia was detected in 11 (24%) patients. The SEC group was more likely to have nonconventional dysplasia (32%, P<0.001), invisible/flat dysplasia (27%, P<0.001), and advanced neoplasia (24%, P<0.001) than the control group (7%, 2%, and 0%, respectively). High-risk nonconventional subtypes (ie, hypermucinous, crypt cell, and goblet cell deficient dysplasias) accounted for 18% of all dysplastic lesions in the SEC group, which were not seen in the control group (P<0.001). The SEC group (n=35; 76%) also had a higher rate of concordance between the location of SEC and the area of synchronous/metachronous dysplasia than the control group (n=22; 49%) (P=0.007). In conclusion, dysplasia detected in patients with SEC is often endoscopically invisible/flat (27%), nonconventional (32%, including the high-risk subtypes), and found in the same colonic segment as SEC (76%), which may in part explain why some patients with SEC are associated with an increased risk of colorectal neoplasia, including advanced neoplasia. The finding of SEC may warrant a careful follow-up colonoscopy with increased random biopsy sampling, especially in the segment of colon with SEC.

中文翻译：

---

在锯齿状上皮变化患者中检测到的不典型增生通常与看不见或扁平的内窥镜外观、非常规不典型增生特征和晚期肿瘤相关。


锯齿状上皮变化（SEC）定义为炎症性肠病（IBD）患者中发现的内镜下不可见的增生性息肉（HP）样粘膜变化，其意义尚不清楚。尽管一些研究报告 SEC 患者发生同步和/或异时结直肠肿瘤（包括晚期肿瘤（高度不典型增生或结直肠癌））的风险增加，但 SEC 的发生与结肠炎症增加并无显着相关性。这与报道的溃疡性结肠炎中结肠炎症增加和结直肠肿瘤风险之间的正相关性形成鲜明对比，反对 SEC 可能代表一种不典型增生的观点。因此，本研究旨在描述 SEC 患者中检测到的同步性和异时性不典型增生的特征，以确定导致结直肠肿瘤风险增加的因素，包括在这些患者的子集中观察到的晚期肿瘤。对 46 名患有 SEC (n=109) 和同步和/或异时性发育不良 (n=153) 的 IBD 患者的临床病理特征进行了分析。所有发育不良病变均分为传统或非传统发育不良亚型。作为对照，我们分析了 45 名具有内窥镜可见 HP 或息肉样 HP (n=75) 以及同步和/或异时性发育不良 (n=87) 的 IBD 患者。 SEC 组包括 28 名男性 (61%) 和 18 名女性 (39%)，平均年龄 58 岁，有长期 IBD 病史（平均病程：23 年）。大多数患者（n=34；74%）患有溃疡性结肠炎，12 名患者（26%）患有克罗恩病。 39 名 (85%) 患者有全结肠炎病史，2 名 (4%) 患者伴有原发性硬化性胆管炎。二十七名 (59%) 患者患有多灶性 SEC。 SEC 主要发现于左结肠 (n=52; 48%) 和直肠 (n=34; 31%)。 SEC 组的不典型增生通常在内窥镜下不可见或平坦（n=42；27%），并表现出非常规的不典型增生特征（n=49；32%）。在 SEC 组中发现了六种非常规亚型，包括 17 例（11%）伴有潘氏细胞分化增加的不典型增生、12 例（8%）粘液性不典型增生、8 例（5%）隐窝细胞不典型增生、7 例（5%）杯状细胞缺陷型不典型增生、 3 例（2%）无蒂锯齿状病变样不典型增生，2 例（1%）传统锯齿状腺瘤样不典型增生。 11 名 (24%) 患者检测到晚期肿瘤。与 SEC 组相比，SEC 组更有可能患有非常规不典型增生 (32%，P<0.001)、隐形/扁平不典型增生 (27%，P<0.001) 和晚期肿瘤 (24%，P<0.001)对照组（分别为 7%、2% 和 0%）。高危非常规亚型（即高粘液性、隐窝细胞和杯状细胞缺陷型发育不良）占 SEC 组所有发育异常病变的 18%，而在对照组中未见（P<0.001）。 SEC 组 (n=35; 76%) SEC 位置与同步/异时性发育不良区域的一致性也高于对照组 (n=22; 49%) (P=0.007)。总之，在 SEC 患者中检测到的不典型增生通常是内镜下不可见/平坦的（27%）、非常规的（32%，包括高危亚型），并且与 SEC 位于同一结肠段（76%），这可能部分解释为什么一些 SEC 患者与结直肠肿瘤（包括晚期肿瘤）风险增加相关。 SEC 的发现可能需要仔细随访结肠镜检查，并增加随机活检取样，特别是在有 SEC 的结肠段。