The Dual Lens of Endoscopy and Histology in the Diagnosis and Management of Eosinophilic Gastrointestinal Disorders-A Comprehensive Review

Abstract

Eosinophilic Gastrointestinal Disorders (EGIDs) are a group of conditions characterized by abnormal eosinophil accumulation in the gastrointestinal tract. Among these EGIDs, Eosinophilic Esophagitis (EoE) is the most well documented, while less is known about Eosinophilic Gastritis (EoG), Eosinophilic Enteritis (EoN), and Eosinophilic Colitis (EoC). The role of endoscopy in EGIDs is pivotal, with applications in diagnosis, disease monitoring, and therapeutic intervention. In EoE, the endoscopic reference score (EREFS) has been shown to be accurate in raising diagnostic suspicion and effective in monitoring therapeutic responses. Additionally, endoscopic dilation is the first-line treatment for esophageal strictures. For EoG and EoN, while the literature is more limited, common endoscopic findings include erythema, nodules, and ulcerations. Histology remains the gold standard for diagnosing EGIDs, as it quantifies eosinophilic infiltration. In recent years, there have been significant advancements in the histological understanding of EoE, leading to the development of diagnostic scores and the identification of specific microscopic features associated with the disease. However, for EoG, EoN, and EoC, precise eosinophil count thresholds for diagnosis have not yet been established. This review aims to elucidate the role of endoscopy and histology in the diagnosis and management of the three main EGIDs and to analyze their strengths and limitations, their interconnection, and future research directions.

Keywords: EGIDs; eosinophilic GI disorders; eosinophilic colitis; eosinophilic esophagitis.

Figure 1

Pathogenesis of Th2 inflammatory drive in Eosinophilic Gastrointestinal Disorders (EGIDs), especially EoE. Exposure to initial food antigens triggers lymphocyte-Th2 activation, resulting in the accumulation of eosinophils in the esophagus. Following stimulation with Eotaxin 3, eosinophil degranulation promotes acute damage to the esophageal epithelium, followed by subsequent chronic fibrotic remodeling of the esophagus, which is dependent on TGF-beta. The copyright of the picture belongs to the authors.

Figure 2

Endoscopic features of Eosinophilic Esophagitis: (A) Linear furrows in the middle esophagus. (B) White exudates covering more than 10% of the esophageal circumference. (C) Prominent rings. (D) Noticeable edema, crepe-paper-like appearance, lumen narrowing, and a mucosal tear resulting from endoscope passage. The copyright for the images belongs to the authors.

Figure 3

Endoscopic Dilation using a Through-the-Scope (TTS) Balloon for an Eosinophilic Esophagitis (EoE)-related stricture: (A) The endoscopic view inside the completely inflated balloon. (B) The balloon during deflation. (C) The final mucosal tear, indicating efficient dilation. The copyright for the images belongs to the authors.

Figure 4

Histological features of Eosinophilic Esophagitis (EoE): (A–C) Biopsy slides of active eosinophilic esophagitis (EoE) include (A) eosinophilic abscesses (thick arrows) and alterations to the surface epithelium (narrow arrows) (20× zoom), (B) dilated intercellular spaces (arrows) (20× zoom), and (C) basal zone hyperplasia (thick arrow) with eosinophil infiltration (narrow arrows) (15× zoom). (D) In cases in which the EoE is in remission, basal zone hyperplasia and papillary elongation (narrow arrows) are evident. Rare eosinophils are present (15× zoom). The copyright for the images belongs to the authors.

Figure 5

Endoscopic view of active Eosinophilic Gastritis (EoG): fold scalloping with granularity/nodularity in the subangular region.

Figure 6

Histological slide of Eosinophilic Gastritis (EoG): Typical findings are eosinophil infiltrates (narrow arrow) and spongiosis (thick arrows) (18× zoom).

Figure 7

Endoscopic features of Eosinophilic Colitis (EoC): Notable signs are (A) erythema, (B) loss of vascular pattern, and (C) minute erosions.