肥大细胞是肠道的常驻细胞，在宿主防御和其他重要功能中发挥着重要作用。肥大细胞的失调已被认为是多种肿瘤性、炎症性和功能性疾病的病理发生机制之一，其中一些疾病可以表现为肠道症状。因此，外科病理学家必须面对何时以及如何评估肠道生物组织中的肥大细胞，以及这些决策是否应基于形态学标准、临床背景或临床同僚的直接要求。在评估肥大细胞浸润方面，病理学家在系统性肥大细胞增多症的诊断中扮演最佳角色，形态学评估与辅助检查的实用价值已被证实。相反，在非肿瘤性肥大细胞疾病中，如肥大细胞激活综合征、肠易激综合征或所谓的“肥大细胞性肠炎”，组织病理学的作用存在争议。尽管如此，在后一种情况下，病理学家对肥大细胞计数的请求有了显著增加，尽管这些请求没有受到出版证据的支持。此外，一个肠道生物组织中“正常”的肥大细胞数量还没有被明确。因此，在实践中如何处理这些请求存在相当大的差异。本综述评估并总结了在各种临床情况下评估内镜肠生物组织中肥大细胞的出版证据，旨在为外科病理学家提供实用、基于证据的指导，以应对关于肠道肥大细胞计数的请求。 本文受版权保护。版权所有。

Mast cells are residents of the tubular gastrointestinal (GI) tract, where they play an important role in host defense and other vital functions. Dysregulation of mast cells has been implicated in the pathogenesis of several neoplastic, inflammatory, and functional disorders, some of which may manifest with GI symptoms. Surgical pathologists must therefore confront when and how to evaluate GI biopsies for mast cells, and whether such decisions should be based on morphologic criteria, clinical context, or direct request from clinical colleagues. The pathologist's role in evaluation of mast cell infiltrates is best defined in the diagnosis of systemic mastocytosis, where the utility of morphologic assessment coupled with ancillary studies is well-established. In contrast, in non-neoplastic mast cell disorders such as mast cell activation syndrome, irritable bowel syndrome, or so-called "mastocytic enterocolitis," a role for histopathology, if any, is controversial. Despite this, pathologists have seen a sharp increase in requests for mast cell quantification in the latter setting, despite these requests not being supported by published evidence. Moreover, what constitutes a 'normal' number of mast cells in a luminal GI biopsy is not well-established. As a result, there is considerable variation in how these requests are handled in practice. This review evaluates and summarizes the published evidence relating to mast cell evaluation in endoscopic GI biopsies in various clinical scenarios, with a goal of providing practical, evidence-based guidance for the surgical pathologist when approached with requests for mast cell quantification in GI biopsies.This article is protected by copyright. All rights reserved.