Eosinophilic Gastroenteritis

An Update

Alfredo J Lucendo; Angel Arias

Disclosures

Expert Rev Gastroenterol Hepatol. 2012;6(5):591-601. 

In This Article

Histopathology of EGE

There is no established consensus on a diagnostic threshold with regard to eosinophil count for most of EGID. This is due to several reasons, including inconsistencies in definitions of what constitutes an eosinophil (e.g., the presence of a cell defined by a nucleus or an aggregate of granule proteins) and the size of a high power field (hpf); (the nonstandardized area of tissue covered by a 40× light microscope objective), along with variability in analysis between pathologists and gastrointestinal/allergy clinicians.[9,25] EGE diagnostic criteria have thus been based on tissue infiltration by sheets of eosinophils, along with edema that generally involves the submucosa or any layer of the gut, the presence of digestive symptoms and the exclusion of parasitic infections or other causes of eosinophilia.[52] With the exception of the esophageal squamous epithelium, which normally contains no eosinophils, their presence in the remainder of the luminal gut is poorly defined.[24,53] Information regarding the quantity and location of eosinophils in the GI tract has been provided for healthy children;[24] examination of the antrum, fundus and small intestine revealed none or minimal eosinophils in the surface epithelium, while an average of two to ten cells/hpf was documented in lamina propria of the stomach and duodenum, respectively. Additionally, atopic and nonatopic patients had comparable numbers of eosinophils. Likewise, there is only limited histopathological information on the additional features in EGE.

In contrast to EoE, where a histopathological diagnostic threshold of ≥15/hpf has been consensually defined, such a threshold has not been established for EGE; however, the limit of ≥20/hpf is the most commonly agreed upon.[13,16] A recent study evaluating EGE-associated histopathological findings included sheets of eosinophils, frequent involvement of the muscularis mucosa or submucosa and a density of ≥30 eosinophils/hpf in at least 5 hpf as diagnostic criteria of 'histological eosinophilic gastritis' in the absence of known causes of eosinophilia.[54] Eosinophilic degranulation or cryptitis has also been recognized as a typical criterion,[13] but epithelial infiltration may not be a constant feature.[54] These proposed criteria seem robust as they exhibited no differences between gastric antrum and corpus, and no significant seasonal, age or geographic variations.[54]

A lack of association between Helicobacter pylori infection and EGE has been reported.[54] Likewise, superinfection by the protozoa Isospora belli, a common opportunistic parasite in inmmunodepressed patients, is considered to be an exceptional association in EGE.[55]

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