Pediatric adenomatous polyposis syndromes: an update.

Juvenile polyps are a common finding in the pediatric population. In contrast, colon adenomas, which are viewed as dysplastic precancerous lesions, are found sporadically in late adulthood. Adenomas in children and young adults are highly unusual and suggest one of several forms of inherited colorectal cancer. These disorders show a predilection to early adenoma formation and can present in childhood. Familial adenomatous polyposis and Lynch syndrome are autosomal dominant, often with involvement of multiple family members, or can be seen in an individual arising from a de novo mutation. The most recently described adenomatous polyposis syndrome, MutYH-associated polyposis, is autosomal recessive, requiring an inherited mutation from each parent. All three adenomatous polyposis disorders can display tremendous variation in expression, even within the same family, and can have a common overlapping phenotype. These disorders require regular medical care to minimize cancer risk in the digestive tract and in other organ systems.