Cancer of the digestive tract is a major cause of cancer-associated morbidity and mortality worldwide. Secondary prevention and treatment of early lesions is extremely important because the etiology of gastrointestinal cancer remains largely unknown. Precursor lesions can be identified with imaging techniques and histology. The macroscopic pattern seen during endoscopy includes polyps and non-polypoid lesions. The microscopic epithelial alterations of the precursor lesions include cytological and architectural abnormalities formerly called “dysplasia”. Recently, “dysplasia” has been replaced by “intraepithelial neoplasia”. Although intraepithelial or non-invasive neoplasia forms a spectrum, reflecting underlying genetic abnormalities, the lesion is usually graded according to the degree of severity. Follow up and treatment strategies are planned accordingly. It has been recognised also that “hyperplastic polyps”, which do not necessarily show the features of intraepithelial neoplasia are in fact a heterogeneous group and some of these have neoplastic potential. The definition of malignancy and the microscopic features used for the identification of cancer are not universally uniform. Therefore, comparison of articles from different continents is not always possible. In order to avoid confusion, new terminologies and definitions have been proposed and are currently introduced. The purpose of this minireview is to describe the most recent terminologies and definitions, which can be correlated with treatment strategies.