Eosinophilic Esophagitis - Cory A. Roberts, M.D.

Eosinophilic Esophagitis, By Cory A. Roberts, M.D.

Eosinophilic esophagitis (EE) is an increasingly reported and previously under recognized entity. This condition was first described in 1978 by Landres et al and further by Lee in 1985.

It typically occurs in young adult males presenting with dysphagia and/or food impaction. Many of these patients, probably the majority, have concomitant allergies or asthma but lack peripheral eosinophilia. The male preponderance is 4:1 with the average patient less than 45 years old based on several studies.

Endoscopically, myriad findings have been reported. Some 10% of cases will show relatively normal mucosa. Other endoscopic findings include multiple rings sometimes referred to as "feline esophagus", corrugations, furrows, vertical lines, friable mucosa ("crepe-paper mucosa") and even white pinpoint exudates. The white exudates have been attributed to eosinophilic microabscesses microscopically although this is not proven. The endoscopic finding of friable mucosa has been offered as pathognomonic for the condition but larger studies are necessary to confirm that claim.

The microscopic features are impressive but overlap with typical reflux esophagitis. That is likely one of the reasons the condition is currently under recognized and was not identified as a unique entity for some time. Specifically, the histologic hallmarks are spongiosis, basal hyperplasia, elongation of the papillae with vascular ectasia and pronounced eosinophilic infiltration. The eosinophils are often more prominent in the luminal half of the epithelium and form microabscesses or clusters of three or more eosinophils. As pathologists have a desire for absolutes, many studies have focused on counting the number of eosinophils in a high power field in order to arrive at a definitive and objective standard. The data support the notion that somewhere in the range of 15 to 20 eosinophils per high power field is an appropriate threshold for a diagnosis of EE.

Given the histologic findings in EE it is certain that many cases currently and in the past have been labeled severe reflux. Equipped with the appropriate clinical information and paying close attention to it should afford the pathologist an opportunity to suggest the possibility of EE when appropriate. Specifically, one ought to pay close attention to the age and gender (young males); presenting symptom(s) (dysphagia and/or food impaction) and location of biopsies. It would be extremely unusual to see the histology described above in a biopsy from the proximal esophagus in a condition other than EE. That is, reflux would not likely produce such impressive histology proximally. In my experience, an esophageal ring can elicit an eosinophilic inflammatory response with much of the other typical reflux-type histology but dense eosinophilic inflammation would be unusual and should be a cause for concern.

References:
1. Lee R. Marked eosinophilia in esophageal mucosal biopsies. Am J Surg Pathol 1985;9:475-479.

2. Landres RT, Kuster GG, Strum WB. Eosinopilic esophagitis in a patient with vigorous achalasia. Gastroenterology 1978 1298:1301.

3. Sgouros SN, Bergele C, Mantides A. Eosinophilic esophagitis in adults: a systematic review. Eur J Gastroenterol Hepatol 2006 18:211-217.

4. Parfitt JR, Gregor JC, Suskin NG, Jawa HA, Driman DK. Eosinophilic esophagitis in adults: distinguishing features from gastroesophageal reflux disease: a study of 41 patients. Mod Pathol 2006 19, 90-96.