Background

The diagnosis of inflammatory bowel disease (IBD) is usually established after the development of symptoms, but preclinical disease may be present years before the final diagnosis. Recently, histology has become one of the main outcomes of IBD treatment. The primary aim of our study was to define the main histological findings of preclinical IBD and its association with the natural history of the disease.

Methods

This multicentric, retrospective study included all patients who participated in the colorectal cancer screening programme in 11 centres between 2009–2014. All patients were firstly assessed by a faecal immunochemical test (OC-Sensor, Eiken Chemical Co., Tokyo, Japan) and, if this test was positive (cut-off 20 μg Hgb/g), a colonoscopy was performed. All patients had an incidental diagnosis of IBD confirmed by histology, according to current ECCO criteria, during a screening colonoscopy. Three histologic findings were evaluated at diagnosis: presence of granuloma, crypt abscesses and/or eosinophilic infiltrate. The main outcomes were the development of symptoms and the risk of proximal disease extension. The frequency of each finding was described separately by IBD subtype and the chi-square test was used to describe possible association with the main outcomes.

Results

During this period we performed 31,005 colonoscopies after 498,227 FIT. Finally, 110 patients were included with an incidental diagnosis of ulcerative colitis (UC, 79 cases), Crohn’s disease (CD, 24 cases) or IBD-Unclassified (IBD-U, 7 cases). Crypt abscesses were present in 56%, 33% and 57% of UC, CD and IBD-U patients, respectively (Figure 1). An eosinophilic infiltrate was observed in 27%, 25% and 57% of patients, respectively. Granuloma were only observed in 4% of CD patients. There were no statistically significant differences in these findings according to IBD subtype (p = 0.14, 0.22 and 0.17 for crypt abscesses, eosinophilic infiltrate and granuloma, respectively). After a median follow-up of 25 months (IQR, 11–42), 36% of patients developed symptomatic disease. Neither of the histological findings were associated with a higher risk of developing symptomatic disease (p = 0.29, 0.78 and 0.3, respectively). No patient showed proximal extension of UC.

Conclusion

Preclinical IBD is frequently associated with the presence of crypt abscesses, especially in UC. Granuloma is probably a late finding in CD. Around one third of patients show a eosinophilic infiltrate in the early phases of the disease.

中文翻译：

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P159临床前炎症性肠病的组织病理学发现

背景

炎症性肠病（IBD）的诊断通常是在症状发展后确定的，但是临床前疾病可能在最终诊断之前就已经存在。最近，组织学已成为IBD治疗的主要结果之一。我们研究的主要目的是确定临床前IBD的主要组织学发现及其与疾病自然史的关系。

方法

这项多中心，回顾性研究纳入了2009-2014年间11个中心参加结直肠癌筛查计划的所有患者。首先通过粪便免疫化学测试（OC-Sensor，Eiken Chemical Co.，东京，日本）对所有患者进行评估，如果该测试呈阳性（临界值为20μgHgb / g），则进行结肠镜检查。根据当前的ECCO标准，在筛查结肠镜检查期间，所有患者均经组织学确诊为IBD。诊断时评估了三个组织学发现：肉芽肿，隐窝脓肿和/或嗜酸性粒细胞浸润。主要结果是症状的发展和近端疾病扩展的风险。

结果

在此期间，我们在498227 FIT之后进行了31005例结肠镜检查。最后，110例患者被诊断为溃疡性结肠炎（UC，79例），克罗恩病（CD，24例）或IBD未分类（IBD-U，7例）。UC，CD和IBD-U患者分别有56％，33％和57％出现地穴脓肿（图1）。分别在27％，25％和57％的患者中观察到嗜酸性细胞浸润。仅在4％的CD患者中观察到肉芽肿。根据IBD亚型，这些发现没有统计学上的显着差异（隐窝脓肿，嗜酸性浸润和肉芽肿分别为p = 0.14、0.22和0.17）。中位随访25个月（IQR，11-42）后，36％的患者出现了症状性疾病。两种组织学检查结果均与发生症状性疾病的较高风险无关（分别为p = 0.29、0.78和0.3）。没有患者显示UC近端扩展。

结论

临床前IBD通常与隐窝脓肿的存在有关，尤其是在UC中。肉芽肿可能是CD的晚期发现。大约三分之一的患者在疾病的早期表现出嗜酸性浸润。