Virtual Medical Centre

Colonic polyps and hereditary polyposis syndromes

• What is Colonic polyps and hereditary polyposis syndromes?
• Who gets Colonic polyps and hereditary polyposis syndromes?
• Predisposing Factors
• Progression
• Probable Outcomes
• How is Colonic polyps and hereditary polyposis syndromes Diagnosed?
• How is Colonic polyps and hereditary polyposis syndromes treated?
• Colonic polyps and hereditary polyposis syndromes References

What is Colonic polyps and hereditary polyposis syndromes?

Colonic polyps is a disease of the Gastro-intestinal tract. A "polyp" is any elevation above the surface of the lining of the gut (the mucosa). Polyps can range in size from several millimeters to up to 10cm in size. Polyps can be found on their own, or in multiples (in particular in the hereditary syndromes). The importance of polyps, is that some of them (in particular adenomas) have malignant potential - the potential to lead to colorectal cancer. Polyps can thus be separated into non-neoplastic, and neoplastic. Non-neoplastic: "Hamartomatous" - meaning of an unusual make-up - include "juvenile" polyps, and the polyps found in Peutz-Jeghers syndrome. Neoplastic: Adenomas - may be single, or multiple. In Familial Adenomatous Polyposis there are more than a hundred.

Who gets Colonic polyps and hereditary polyposis syndromes?

Approximately 1 in 10,000 of people have the mutant APC gene responsible for Familial Adenomatous Polyposis (FAP). There are a couple of variants of FAP - Gardner's syndrome, and Turcot's syndrome, but they involve the same gene. Non-adenomatous polyposis syndromes are rare.

Predisposing Factors

The familial conditions, both the non-neoplastic ones (Juvenile polyposis, Peutz-Jeghers) and the neoplastic (FAP) are all autosomal dominant. That means that a person needs only one abnormal gene (from either parent) to have the disorder - hence they are passed on very easily. More commonly, however, colonic adenomas may occur without a genetic predisposition in any other person. In fact most people with adenomas (which are usually the precursor to colon cancer) do not have a genetic syndrome like the above.

Progression

Individuals with FAP will almost inevitably develop colon cancer during their thirties. There is also an increased risk of other gastrointestinal malignancies such as adenocarcinoma of the duodenum and gastric and ileal adenocarcinomas. - Peutz-Jeghers is associated with a slightly increased risk of development of small and large bowel cancers, as well as other tumours - of the ovary and pancreas. - Juvenile polyposis is associated with an increased risk of colorectal cancer.