Beige mucosa observable under narrow‐band imaging indicates the active sites of eosinophilic esophagitis

BACKGROUND AND AIM: The majority of patients with eosinophilic esophagitis (EoE) are likely to have observable features under narrow‐band imaging, namely beige mucosa. However, the histological features and clinical implications of beige mucosa have not been investigated. The aim of this study was to determine whether beige mucosa could serve as an endoscopic marker for predicting active inflammatory sites of EoE. METHODS: We retrospectively analyzed both the narrow‐band images and biopsied specimens of 77 esophageal lesions from 35 consecutive patients with EoE. We divided these specimens into two groups: target biopsied specimens from beige mucosa (beige group) and specimens biopsied from non‐beige mucosa (non‐beige group). The number of eosinophils per high‐powered field, thickness of the superficial differentiated cell layer, and depth of the hemoglobin component from the surface layer were compared between the two groups. RESULTS: Forty‐four out of the 45 specimens were diagnosed as histological active lesions in the beige group. The sensitivity, specificity, and overall accuracy of beige mucosa in predicting EoE activity were 97.8%, 96.9%, and 97.8%, respectively. Compared with the non‐beige group, specimens in the beige group had a significantly thinner superficial differentiated cell layer. CONCLUSIONS: Beige mucosa is associated with thinning of the normal superficial differentiated cell layer, and these histological changes in the active inflammatory sites of EoE could be recognized endoscopically as color differences. Beige mucosa may serve as an endoscopic indicator for predicting the histological activity of EoE.