Supplementary Material for: Detection rates of non-cavitary epithelioid cell granuloma by gastrointestinal biopsy in patients with treatment-naïve Crohn's disease

Introduction: Detecting non-cavitary epithelioid cell granuloma by gastrointestinal biopsy is important in the initial diagnosis of Crohn’s disease (CD). In the present study, we aimed to determine the rate of granuloma detection by gastrointestinal biopsy according to the number of biopsies performed.
Methods: The present study included patients newly diagnosed with CD at our hospital between April 2017 and March 2023. During endoscopic examinations, biopsy specimens were taken from affected lesions. Initially, one section per biopsy was examined to detect granuloma. In cases where no granuloma were detected, step sections were additionally prepared and examined. The rate of granuloma detection by gastrointestinal biopsy were retrospectively examined.
Results: A total of 30 patients with a new diagnosis of CD were included in this study. In total, 284 gastrointestinal biopsies were performed in 29 cases. The rate of granuloma detection by gastrointestinal biopsy per case was 58.6% (17 out of 29 cases). The rate of granuloma detection by gastrointestinal biopsy per biopsy was 6.0% (17 out of 284 biopsies) on initial histological examination, and 11.6 % (33 out of 284 biopsies) following examination of step sections. The rate of granuloma detection was significantly improved by performing histological examination of step sections compared with initial examinations (P < 0.05).
Conclusion: The rate of granuloma detection per biopsy was 11.6%, even after histological examination of step sections. These results indicate that performing multiple intestinal biopsies and assessing for the presence of granuloma using multiple section examinations is required in the initial diagnosis of CD.

引言：通过胃肠道活检检测非干酪样上皮样细胞肉芽肿（non-cavitary epithelioid cell granuloma），对克罗恩病（Crohn’s disease，CD）的初始诊断具有重要临床意义。本研究旨在明确不同活检数量下胃肠道活检的肉芽肿检出率。
方法：本研究纳入2017年4月至2023年3月于我院新确诊为CD的患者。内镜检查期间，于病变部位采集活检标本。初始阶段，每份活检标本仅制备1张切片用于肉芽肿检测；若未检出肉芽肿，则追加制备连续切片并再次检测。本研究对胃肠道活检的肉芽肿检出率进行了回顾性分析。
结果：本研究共纳入30例新诊断CD患者，其中29例完成了共计284次胃肠道活检。按病例统计的肉芽肿检出率为58.6%（29例中17例）。初始组织学检查中，按活检标本统计的检出率为6.0%（284份活检标本中17份）；经连续切片检查后，检出率升至11.6%（284份活检标本中33份）。与初始检查相比，连续切片组织学检查可显著提高肉芽肿检出率（P < 0.05）。
结论：即便经连续切片组织学检查，单份活检标本的肉芽肿检出率仍仅为11.6%。上述结果表明，在CD的初始诊断中，需采集多份肠道活检标本，并通过多切片检查评估肉芽肿的存在与否。