RESUMEN
AIMS: The Vienna classification is used to classify dysplasia in Barrett's oesophagus (BO), but reproducibility and value of diagnosis of lower grades in particular are often questioned. The aim was to test the diagnostic variability and correlation with patient outcome and to attempt to define histological features causing discrepant diagnoses, as well as to test the impact of adding p53 immunohistochemistry on reproducibility and prediction of outcome. METHODS AND RESULTS: One hundred and forty-three patients with 154 sets of biopsy specimens originally diagnosed with Barrett's dysplasia were retrieved from the pathology records of Nottingham University Hospital. Thirty-two Barrett's patients without dysplasia were added. Anonymized slides were graded independently by five pathologists without and with p53-stained slides. Interobserver variation, correlation with outcome and diagnostic accuracy were determined. Weighted kappa scores between pairs of pathologists showed substantial agreement and improved after p53 immunohistochemistry. Agreement with the original diagnosis was substantially lower. Fourteen of 34 low-grade dysplasias (LGD) and 27 of 30 high-grade dysplasias on consensus progressed within 10 years compared with 18/94 and 28/39 of original diagnoses. Progression correlated with p53 positivity. CONCLUSION: The Vienna classification is useful and reproducible in BO. Consensus diagnosis by gastrointestinal pathologists produces high specificity and predictive value, even for LGD. p53 immunohistochemistry assists in diagnosis in difficult cases and predicts progression.