Nuanced evaluation of adenoma-carcinoma sequence in colorectal carcinoma. What is the role of serrated adenomas?

Colorectal adenocarcinoma is one of the most frequent malignancies. Efficient and useful screening strategies are available therefore the knowledge of precursor lesions is crucial. These precursor lesions, the so called adenomas can be subdivided into several histological subgroups. These subgroups display a distinct molecular profile as well as distinct clinical characteristics. Today, classical adenomas with tubular, tubulo-villous and villous morphology are distinguished from serrated lesions, encompassing hyperplastic polyps, sessile serrated adenomas and traditional serrated adenomas. Similar to the classical adenoma carcinoma pathway the sessile and traditional serrated lesions can proceed to an invasive carcinoma. These carcinomas display distinct molecular, clinical and phenotypical characteristics similar to their precursor lesions. These differences are important for cancer prevention, adequate therapy and have prognostic implications.