Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
California Animal Health and Food Safety Laboratory System, University of California-Davis, San Bernardino, CA, USA.
J Vet Diagn Invest. 2022 May;34(3):376-388. doi: 10.1177/10406387221085584. Epub 2022 Mar 31.
Evaluation of gastrointestinal (GI) biopsies is a multistep process that includes reviewing an appropriate history, determining sample quality, and evaluating histologic sections. Selected diagnostic parameters that, in combination with intestinal histopathology, can be useful to localize disease to the intestinal tract in the horse include hypoproteinemia and hypoalbuminemia, ultrasound evidence of increased thickness of the small intestinal wall, and alterations in glucose or D-xylose absorption tests. Biopsies may be acquired either endoscopically, or via laparoscopy or standing flank incisional approaches. GI sections should be evaluated using a systematic approach that includes both architectural changes and inflammatory cell infiltrates. Although strategies have been developed for assessment of GI biopsies from the dog and cat, a standardized approach to interpretation of the equine GI biopsy has yet to be developed. GI biopsies pose several challenges to the pathologist, especially for endoscopic biopsies in which the quality of the specimen and its orientation may vary greatly. Architectural changes are arguably the most critical changes to evaluate. In a horse with chronic GI inflammation, such as occurs in idiopathic inflammatory bowel disease (IBD), the cell types encountered frequently are macrophages, eosinophils, lymphocytes, and plasma cells. Increased numbers of these cell types are categorized loosely as mild, moderate, and severe. Specific forms of idiopathic IBD have been further classified by this infiltrate as granulomatous enteritis, eosinophilic enteritis, and lymphoplasmacytic enteritis; there is limited information on microscopic changes with each. Unfortunately, microscopic GI lesions are usually nonspecific, and determination of etiology requires further investigation.
胃肠道（GI）活检的评估是一个多步骤的过程，包括回顾适当的病史、确定样本质量以及评估组织学切片。一些有诊断价值的参数，结合肠道组织病理学，可以有助于将疾病定位到马的肠道，包括低蛋白血症和低白蛋白血症、超声显示小肠壁厚度增加，以及葡萄糖或 D-木糖吸收试验的改变。活检可以通过内窥镜、腹腔镜或站立式侧腹切开术获得。GI 切片应使用包括结构改变和炎症细胞浸润在内的系统方法进行评估。虽然已经为犬和猫的 GI 活检评估制定了策略，但尚未为马的 GI 活检制定标准化的解释方法。GI 活检给病理学家带来了一些挑战，尤其是对于内窥镜活检，其标本的质量和方向可能差异很大。结构改变是最需要评估的关键变化。在患有慢性胃肠道炎症的马中，如特发性炎症性肠病（IBD），常见的细胞类型是巨噬细胞、嗜酸性粒细胞、淋巴细胞和浆细胞。这些细胞类型的数量增加被归类为轻度、中度和重度。特发性 IBD 的具体形式也根据这种浸润被进一步分为肉芽肿性肠炎、嗜酸性粒细胞性肠炎和淋巴浆细胞性肠炎；每种疾病的微观变化信息都很有限。不幸的是，微观 GI 病变通常是非特异性的，病因的确定需要进一步调查。
