The pathology of hereditary polyposis syndromes.

Our understanding of the genetics and pathology of familial colorectal cancer continues to evolve with both the discovery of underlying genetic defects and the description of entirely new entities. Genetic analysis has demonstrated phenotypic overlap between some of these syndromes, such that their nosology is rapidly becoming based on genetics with clinicopathological features playing a secondary, but important, role. Further clinical characterization of these syndromes has also demonstrated widely differing risks for the development of colorectal cancer and a range of other malignancies with implications for both the affected patient and members of their families. This review aims to outline the clinical, pathological and genetic features of this increasingly complex group of diseases.