溃疡性结肠炎相关肿瘤（UCAN）的特点是多灶性肿瘤发生。据报道，UCAN 内镜治疗后出现了广泛的异时性病变，这表明 UCAN 治疗的病变中出现了散发性肿瘤。因此，我们的目的是评估溃疡性结肠炎（UC）患者粘膜内病变的特征和临床病理学特征的免疫组织化学（IHC）差异。我们检查了来自UC患者的全结肠切除术中因癌或不典型增生而切除的35个粘膜内病变和71个散发性腺瘤(SAs) 通过内窥镜从没有 UC 的患者身上切除。 UC病变分为传统UCAN组（定义为p53突变模式和β-连环蛋白正常表达）和非传统UCAN组（定义为其余）。使用 IHC 比较 Ki-67 分布、α-甲基酰基辅酶 A 消旋酶 (AMACR) 表达和粘蛋白表型，并研究临床病理特征。常规和非常规UCAN病变位于左侧结肠和直肠。相对于 SA 病变，UCAN 病变发生在更年轻的患者中，并且在肿瘤隐窝中表现出更频繁的 Ki-67 基础分布。传统的 UCAN 病变往往是非多倍体，并且与 SA 病变相比，正常 AMACR 表达的频率更高。 UC 病变具有异质性——8 名多发性病变患者中，只有 2 名病变（均为非传统 UCAN 病变）表现出一致的 IHC 染色特征。Ki-67 分布的基础模式、AMACR 的正常表达和非肠粘蛋白表型被确定为暗示 UCAN 的特征。非息肉状生长是 UCAN 的另一个关键特征。© 2024 John Wiley

Ulcerative colitis-associated neoplasia (UCAN) is characterised by multifocal tumourigenesis. A wide range of metachronous lesions have been reported to occur after endoscopic treatment of UCAN, which suggests the development of sporadic tumours in lesions treated as UCAN. Therefore, we aimed to evaluate differences of immunohistochemistry (IHC) in features and clinicopathological characteristics of intramucosal lesions in patients with ulcerative colitis (UC).We examined 35 intramucosal lesions resected for carcinoma or dysplasia by total colectomy from patients with UC and 71 sporadic adenomas (SAs) endoscopically resected from patients without UC. UC lesions were divided into the conventional UCAN group, defined as p53 mutant pattern and normal expression of β-catenin, and the non-conventional UCAN group, defined as the rest. Ki-67 distribution, α-methylacyl-CoA racemase (AMACR) expression and mucin phenotypes were compared using IHC, and clinicopathological characteristics were investigated. Conventional and non-conventional UCAN lesions were located in the left colon and rectum. Relative to the SA lesions, UCAN lesions occurred in much younger patients and exhibited more frequent basal distribution of Ki-67 in tumour crypts. Conventional UCAN lesions tended to be non-polyploid and exhibited a higher frequency of normal AMACR expression than SA lesions. UC lesions were heterogeneous-only two of the eight patients with multiple lesions had lesions (both non-conventional UCAN lesions) exhibiting concordant IHC staining features.The basal pattern of Ki-67 distribution, normal expression of AMACR and a non-intestinal mucin phenotype were determined as characteristic features suggestive of UCAN. Non-polypoid growth was another a key feature of UCAN.© 2024 John Wiley & Sons Ltd.