Rectal Squamous Cell Carcinoma in a Patient with Familial Adenomatous Polyposis

Squamous cell carcinoma of the rectum is extremely rare, with an incidence between 0.25 and 1 case per 1,000 cases of colorectal carcinoma. In familial adenomatous polyposis (FAP), characterized by the progressive development of hundreds to thousands of adenomatous colonic polyps, unscreened patients and those who are not treated at an early stage of the disease have an extremely high risk of developing colorectal adenocarcinoma. A few reports of squamous cell carcinoma of the rectum have been published but none of the patients had FAP. Here, we report the case of a 17-year-old male with FAP who developed rectal squamous cell carcinoma. (Korean J Med 2015;88:335-339)