A more extensive view of the entire large bowel is
provided with a longer tube called a colonoscope.
Detailed exploration of problem areas in the large intestine may
be carried out. Polyps may be biopsied or removed through the colonoscope.
Light sedation is required, along with a specific bowel preparation.
Colonoscopy is suggested as a screening procedure for families with
atypical or attenuated FAP since adenomas may predominate
in the upper part of the colon.
An x-ray of the colon and rectum is not recommended to diagnose
FAP because adenomas are often very small and are easily missed
or mistaken for stool particles. Moreover, if polyps are observed,
the patient will have to return for a scope and biopsy to confirm
the type of polyp and degree of change within the polyp.