Evaluation of the dysplastic changes evolving in mucosa of various segments of gastrointestinal tract is a part of routine practice. Morphologically different or non-conventional types of dysplastic changes are described in the mucosa of gastrointestinal tract besides the most common conventional type of dysplasia. Non-conventional dysplasias can arise de-novo or they can be found in association with chronic gastrointestinal conditions, such as Barretts esophagus, chronic atrophic gastritis, and inflammatory bowel disease. Non-conventional types of dysplasia include serrated, crypt base of foveolar dysplasia and lesions as pyloric or oxyntic gland adenoma. Non-conventional types of dysplasia arising in inflammatory bowel disease represent specific category with broad morphological spectrum of changes. The aim of this work is to present a comprehensive review of morphological characteristics of individual subtypes of non-conventional dysplastic changes with focus on differences and specificity in particular parts of gastrointestinal tract and provide a functional handout for daily diagnostic practice.
Keywords: Dysplasia; IBD-associated dysplasia; foveolar dysplasia; intraepithelial neoplasia; non-conventional type; serrated dysplasia.