Esophageal subepithelial fibrosis and hyalinization are features of eosinophilic esophagitis

Eosinophilic esophagitis (EE) is characterized by marked esophageal mucosal eosinophilia on histological examination. Although the clinical and histological features of EE are increasingly recognized, the overlap of clinical symptoms and histological findings with gastroesophageal reflux disease (GERD) can lead to diagnostic difficulty. In children with EE we sought to define the frequency of subepithelial fibrosis and define the clinical correlates of this feature. The specificity of this finding in EE was obtained by comparison with a matched group of children with GERD, to ascertain its usefulness as a histological aid in differentiating between the 2 diagnoses.

Comparison was made between 27 patients with EE and 24 patients with GERD, whose endoscopic biopsy specimens included subepithelial tissue. Demographic data, symptoms, endoscopic findings, and other histological findings were also compared.

In contrast to patients with GERD, those with EE more commonly reported longer periods of symptoms (especially dysphagia) and were more likely to have endoscopic abnormalities. Subepithelial fibrosis was present in 89% of patients with EE and 37.5% of patients with GERD (P < 0.0001). The features of fibrosis in EE included uniformity and hyalinization, whereas the fibrosis in GERD was predominantly associated with lymphoid tissue.

Subepithelial fibrosis commonly occurs in children with EE and is associated with increased age and length of symptoms. We propose that along with mucosal eosinophilic infiltration the presence of subepithelial fibrosis is a feature of EE.