Intraepithelial neoplasia (
IEN) is the development of a benign
neoplasia or high-grade
dysplasia in an
epithelium. The exact dividing line between dysplasia and neoplasia has been very difficult to draw throughout the era of medical science. It varies between persons. In the localizations shown below, the term
intraepithelial neoplasia is used to describe more accurately what was historically referred to as
epithelial dysplasia. IEN is not
cancer, but it is associated with higher risk for developing cancer in future. It is thus sometimes a
precancerous condition.