Endoscopic appearance and location dictate diagnostic yield of biopsies in eosinophilic oesophagitis

Summary Background Acknowledging that eosinophilic esophagitis (EoE) is a disease with variable involvement throughout the oesophagus, studies have suggested a minimum of five biopsies to diagnose EoE. Although it is accepted that furrows and exudates appear to represent areas of inflammation, no research to date has looked specifically at EoE endoscopic findings to see if eosinophilic infiltrate correlates with specific endoscopic findings. Aim To evaluate the distribution of eosinophils in EoE and determine whether endoscopic appearances predict the degree of eosinophilia at various locations of the oesophagus. Methods We performed a prospective cross sectional study of EoE (treated and untreated) patients to study the distribution of eosinophils according to endoscopic findings. The oesophagus of 10 EoE patients were biopsied up to 32 times in a circumferential manner. The mucosal changes were documented at the site of each biopsy. Histological determination of eosinophil counts and related histopathology of the oesophagus were then correlated with endoscopic findings. Similar biopsy assessments were made in treated (resolved) EoE patients (n = 6) to determine the permanence of specific endoscopic appearances. Results A total of 16 patients were biopsied (10 EoE, 6 treated EoE). A total of 432 biopsies were obtained in all with 294 biopsies from 10 EoE subjects. Eosinophil density was increased distally in the majority of EoE patients. Biopsies performed in areas of exudates and furrows demonstrated higher eosinophil counts. Lines and normal-appearing oesophagi in EoE subjects were not commonly associated with elevated eosinophil counts (>15 eos/HPF). Rings alone without associated furrows or plaques did not demonstrate elevated eosinophil counts and were seen in resolved EoE (Rx-EoE) as well as in active EoE patients. Conclusions Eosinophilic esophagitis remains a variable disease with some patients manifesting extensive disease throughout the oesophagus. Characteristics of furrows and exudates found during endoscopy are associated with higher peak eosinophil counts, requiring fewer biopsies to make a diagnosis. Lines and otherwise normal appearances of the oesophagus suggest a milder mucosal eosinophilia, requiring substantial biopsies to adequately identify fields with diagnostic eosinophil counts.