Non-adenomatous colorectal polyposis syndromes

Gastrointestinal polyps are common lesions that usually present singly or in small numbers. Although the term ‘multiple colorectal polyposis’ was originally applied to patients carrying at least 100 large intestinal adenomas, it has subsequently become broadened to include patients carrying multiple polyps regardless of their nature. Most of the non-adenomatous polyposis syndromes are hereditary. They can be classified according to the dominant type of polyp, their distribution in the gastrointestinal tract and their potential for the development of gastrointestinal cancers. This review summarises their main clinical, genetic and histopathological features.