title: Classification of eosinophilic gastrointestinal diseases.
abstract: Diagnosis of eosinophilic gastrointestinal diseases is based on morphological evaluation with regard to localization and density of eosinophil infiltration of the mucosa and/or deeper parts of the oesophagus, stomach, and bowel in biopsy or resection specimens. As with eosinophils in any tissue, in the majority of diseases they are probably a sequel of acute inflammation and do not indicate any specific disease. Eosinophil morphology includes intact cells with bilobated nuclei and eosinophil granules in the cytoplasm and extracellular tissue following activation/degranulation. There is no fixed number of eosinophils that can be used as a cut-off criterion to define disease. Associated histopathological features observed in eosinophilic gastrointestinal disease depend on the site of manifestation and primary disease. Eosinophils are typically increased in allergy-associated colitis in adults and allergic proctocolitis in infants, eosinophilic gastroenteritis and eosinophilic oesophagitis. Their presence can also suggest a drug-induced eosinophilia or the presence of a parasitic infection. In general, eosinophils are increased in inflammatory bowel disease (IBD). They are seen in reflux oesophagitis, coeliac disease, and microscopic and infectious colitis. Eosinophils may be a feature of polyarteriitis nodosa and Churg-Strauss syndrome, and can accompany connective-tissue disease as well as malignant lymphomas and adenocarcinomas of gastrointestinal mucosa.
authors.affiliation: Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, Munich, Germany. susanna.mueller@med.uni-muenchen.de
authors.forename: Susanna
authors.initials: S
authors.lastname: Mueller
mesh_terms: D004802:Eosinophilia / Q000145:classification* / Q000209:etiology / Q000473:pathology*; D005767:Gastrointestinal Diseases / Q000145:classification* / Q000209:etiology / Q000473:pathology*; D006801:Humans