Ferenczi Ádám, Ördög Nóra, Újfaludi Zsuzsanna, Kuthi Levente, Sejben Anita
1 Szegedi Tudományegyetem, Szent-Györgyi Albert Orvostudományi Kar, Pathologiai Intézet Szeged, Állomás u. 1., 6725 Magyarország.
2 Országos Onkológiai Intézet, Sebészeti és Molekuláris Patológiai Osztály Budapest Magyarország.
Orv Hetil. 2025 Mar 16;166(11):427-433. doi: 10.1556/650.2025.33260.
Sessile serrated lesions (SSLs) are not uncommon entities per se, usually localised to the proximal half of the colon and are often flat on endoscopic examination. The presence of dysplasia associated with SSL and, even more so, invasion are considered rare, while dysplastic SSLs (SSL-D) very quickly transform into invasive carcinoma. MLH1 immunohistochemical reaction may help to establish the diagnosis of SSL-D. We present the case of an 88-year-old female patient who presented for colonoscopic resection of suspicious tumours in the coecum and transverse colon. Histological examination revealed medullary carcinoma in the coecum with MLH1 and PMS2 mismatch repair protein deficiency. The polyp removed from the transverse colon was histopathologically confirmed to be SSL with central low-grade dysplasia (SSL-D), confirmed by loss of MLH1, and submucosal invasion was seen at a single focus. A BRAF V600E sequencing was performed to rule out Lynch syndrome, which confirmed the presence of the mutation. Risk factors for SSL-D include older age, the presence of multiple synchronous SSLs and a size greater than 10 mm. In SSL-D, due to the high malignant transformation potential, a complete resection should always be sought. In the SSL – SSL-D – carcinoma sequence, the main driver mutations are in the BRAF and less frequently KRAS genes. In cases with numerous SSLs, the possibility of sessile polyposis syndrome, and less frequently MUTYH-associated polyposis and hereditary mixed polyposis syndrome should also be raised. In both SSL and colorectal carcinoma, microsatellite instability, CpG island methylation phenotype and the presence of BRAF V600E mutation are common. The mismatch repair status can be determined by immunohistochemistry using MLH1, PMS2, MSH2 and MSH6 reactions, the 2 tests complementing each other. Determination of mismatch repair status is crucial for the diagnosis of colorectal carcinoma and the potential indication of immune checkpoint inhibitor treatment. Orv Hetil. 2025; 166(11): 427–433.
无蒂锯齿状病变（SSLs）本身并不罕见，通常位于结肠近端的一半，在内镜检查中常呈扁平状。与SSL相关的发育异常甚至浸润被认为很罕见，而发育异常的SSL（SSL-D）会很快转变为浸润性癌。MLH1免疫组化反应可能有助于SSL-D的诊断。我们报告一例88岁女性患者，因结肠镜切除盲肠和横结肠可疑肿瘤就诊。组织学检查显示盲肠为髓样癌，伴有MLH1和PMS2错配修复蛋白缺陷。从横结肠切除的息肉经组织病理学证实为伴有中央低度发育异常的SSL（SSL-D），通过MLH1缺失得以确认，且在单个病灶处可见黏膜下浸润。进行了BRAF V600E测序以排除林奇综合征，结果证实存在该突变。SSL-D的危险因素包括年龄较大、存在多个同步SSLs以及大小大于10mm。在SSL-D中，由于恶性转化潜能高，应始终寻求完整切除。在SSL-SSL-D-癌序列中，主要驱动突变存在于BRAF基因，KRAS基因较少见。在有大量SSLs的病例中，也应考虑无蒂息肉病综合征的可能性，较少见的还有MUTYH相关息肉病和遗传性混合息肉病综合征。在SSL和结直肠癌中，微卫星不稳定性、CpG岛甲基化表型以及BRAF V600E突变的存在都很常见。错配修复状态可通过使用MLH1、PMS2、MSH2和MSH6反应的免疫组化来确定，这两种检测方法相互补充。确定错配修复状态对于结直肠癌的诊断和免疫检查点抑制剂治疗的潜在指征至关重要。《匈牙利医学周报》。2025年；166(11):427–433。
