Gastrointestinal polyposis is a term given to a group of disorders that are associated with the growth of polyps anywhere within the gastrointestinal tract, including the stomach, small intestine, and large intestine or colon. Names of specific polyposis disorders include: Familial adenomatous polyposis, Peutz-Jeghers syndrome, Juvenile polyposis syndrome, and PTEN hamartoma tumor syndrome (also known as Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome).
Polyps are round lumps of tissue that grow from the surface of the bowel and may cause abdominal pain, bleeding, or intestinal obstruction. Chronic diarrhea, anemia, and low blood protein levels are other possible signs of polyposis. Some children and adults with polyps may have no signs or symptoms for many years. Most polyps in children are non-cancerous or "benign." However, some children who develop polyps have an increased risk of developing gastrointestinal cancers and as well as tumors and cancers in other parts of the body. The risk of cancerous growths increases with age and is greatest during adulthood. Children who develop polyps may have other family members with polyps or with related conditions. Children with polyps may also have other unusual non-gastrointestinal conditions or findings. These include unusual skin lesions or patterns of skin freckling, unusually large head, bone changes seen on xray studies, unusual eye findings detected by an eye specialist, nasal polyps, early tumors of the testicle, ovary, brain, thyroid gland, or liver, or rare congenital vascular disorders.