Diagnosis of Pediatric Non-Esophageal Eosinophilic Gastrointestinal Disorders by Eosinophil Peroxidase Immunohistochemistry

Pediatr Dev Pathol. 2021 Nov-Dec;24(6):513-522. doi: 10.1177/10935266211024552. Epub 2021 Jun 28.


Background: Diagnosis of non-esophageal eosinophilic gastrointestinal disorders requires quantification of tissue eosinophils. Our objective was to evaluate eosinophil peroxidase (EPX) immunohistochemistry (IHC) as a method for histologic diagnosis of eosinophilic gastritis (EG) and eosinophilic duodenitis (EoD).

Methods: We performed a retrospective analysis of biopsies from pediatric EG/EoD cases and controls. Subjects with EG or EoD had ≥30 eosinophils per high power field (eos/hpf) in ≥5 hpf in the stomach and/or ≥3 hpf in the duodenum, respectively. Controls had no histopathologic diagnosis recorded. Tissue eosinophil counts were assessed by hematoxylin & eosin stains. EPX stains were assessed using a unique histopathologic scoring system. Slides were digitized and EPX+ staining area/mm2 was quantified by image analysis.

Results: Twenty-six EG/EoD cases and 40 controls were analyzed. EPX scores and EPX/mm2 levels were markedly elevated in EG/EoD (p ≤ 0.0001). Eosinophil density (eos/mm2) correlated strongly with EPX scores and EPX/mm2 levels in the stomach (r ≥ 0.77) and moderately with EPX scores and EPX/mm2 levels in the duodenum (r ≥ 0.52); (p < 0.0001). EPX quantification identified EG/EoD subjects with high diagnostic accuracy (EPX score: AUC = 1 for EG and EoD; EPX/mm2: AUC = 0.98 (95%CI 0.96-1) for EG, AUC = 0.91 (95%CI 0.81-1) for EoD).

Conclusion: EPX-based assessment of eosinophilic inflammation may facilitate automated histologic diagnosis.

Keywords: digital pathology; eosinophilic esophagitis; eosinophilic gastritis; eosinophilic gastroenteritis; image analysis.

MeSH terms

  • Biopsy
  • Child
  • Enteritis*
  • Eosinophil Peroxidase
  • Eosinophilia
  • Eosinophilic Esophagitis*
  • Eosinophils
  • Gastritis
  • Humans
  • Immunohistochemistry
  • Retrospective Studies


  • Eosinophil Peroxidase

Supplementary concepts

  • Eosinophilic enteropathy