Can histopathologists reliably assess dysplasia in chronic inflammatory bowel disease?

A copy of the standardised classification (SC) proposed for assessing dysplasia in inflammatory bowel disease was circulated to six histopathologists who were asked to apply it to 40 slides from 34 patients with ulcerative colitis to test its reproducibility. The slides were relabelled and recirculated to the pathologists at least one month later. Each was asked to state whether or not key diagnostic features were present before giving a final dysplasia score for the second assessment. Only minor interobserver and intraobserver disagreements were recorded. Pathologists were most consistent at recognising back to back glands, villous mucosal architecture, hyperchromatic nuclei, stratification of nuclei, regenerative nuclei and loss of nuclear polarity. There was poor interobserver agreement in assessing dystrophic goblet cells and columnar mucous cells. Back to back glands, hyperchromatic nuclei, loss of nuclear polarity, stratification of nuclei and columnar mucous cells were considered to be the most important features for determining the severity of dysplasia. As there was poor interobserver agreement in assessing columnar mucous cells and dystrophic goblet cells these features need to be more clearly defined or should be removed from the SC.