Hyperplastic polyposis syndrome is a rare, genetic intestinal disease characterized by the presence of multiple (usually large) hyperplastic/serrated colorectal polyps, usually with a pancolonic distribution. Histology reveals hyperplastic polyps, sessile serrated adenomas (most common), traditional serrated adenomas or mixed polyps. It is associated with an increased personal and familial (first-degree relatives) risk of colorectal cancer. The disease is Monarch Disease Ontology identifier MONDO_0015524 (hyperplastic polyposis syndrome). Also known as: serrated polyposis.