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REFINING THE CLINICAL AND HISTOLOGICAL DIAGNOSTIC CRITERIA OF EOSINOPHILIC ESOPHAGITIS IN THE PEDIATRIC POPULATION

AL Lai¹, S Girgis², Y Liang¹, S Carr¹, HQ Huynh¹
¹Department of Pediatrics; ²Department of Pathology, Faculty of Medicine, University of Alberta, Edmonton, Alberta

Eosinophilic Esophagitis (EE) is a condition characterized by isolated eosinophilic infiltration of the esophagus. The current diagnostic criteria, ie, > 20 eosinophils per high power field (eos/HPF) of esophageal biopsies based on hematoxylin and eosin stain (HE), does not capture all patients with EE.
AIMS: 1) to determine clinical variables that predict EE and 2) to determine if the Luna Eosinophil Granule (LEG) stain provides a more accurate diagnosis of EE compared to HE staining.
METHODS: All HE stained esophageal biopsies' slides of pediatric patients less than 18 years showing esophageal inflammation in a 5 year period (2000 to 2004) were reviewed and the number of Eos/HPF were recorded for each slide. Clinical charts of these patients were collected and reviewed and a number of clinical variables were recorded. Also we randomly selected 3 groups of 20 patients with <5, 5 to 20 and >20 Eos/HPF on the HE stain and re-cut and stained the biopsy slides using the LEG stain method. The number of Eos/HPF was recorded.
RESULT: The number of patients with EE has risen dramatically in the 5 year period. The observed decrease in the number of patients who were not clinically diagnosed with EE but had >20 Eos/HPF on review suggested that the misdiagnosis rate of EE for reflux esophagitis has decreased. The clinically significant variables that predict diagnosis of EE in order of importance were improvement from EE treatment, vertical furrows on endoscopy, final endoscopic diagnosis of EE and the absence of vascular pattern on endoscopy. In comparison to HE stain, LEG stain appeared to be superior in detecting low numbers of Eos/HPF. The mean number of eosinophils seen using HE staining and LEG stain was 24.82 and 38.53, respectively.
CONCLUSION: This study demonstrated that the number of misdiagnosed EE cases decreased over the 5 year period. There was an increase in the number of EE cases seen over and above the number of misdiagnosed cases over this period. The key clinical variables that predict EE were a) improvement from specific EE treatment and b) characteristic endoscopic EE findings confirming the importance of endoscopy and c) the recognition of typical EE endoscopic features in the diagnosis of EE. The LEG Stain potentially can be a more accurate stain in determining the histological diagnosis of EE patient with low numbers of Eos/HPF.
Funding provided by a CIHR Summer Studentship

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