Incidental Finding of Attenuated Familial Adenomatous Polyposis.

Attenuated familial adenomatous polyposis (AFAP) or attenuated adenomatous polyposis coli (AAPC) is defined as the milder polyposis phenotype of classic familial adenomatous polyposis (FAP). FAP syndromes are caused by germline mutations in the adenomatous polyposis coli (APC) gene. AFAP is an inherited autosomal dominant with predominant mutations at the far proximal (5') end of the APC gene. Unlike FAP, AFAP is characterized by the occurrence of fewer than 100 adenomas that are found mostly in the proximal part of the colon with a delayed progression to colorectal cancer (CRC). The lower risk of development of colorectal cancer and extra-intestinal neoplasms is likely attributable to under-diagnosis. However, 2-5% of all CRCs happen because of inherited syndromes which include both hereditary polyposis syndromes and hereditary nonpolyposis colorectal cancer syndrome (HNPCC) or otherwise known as Lynch syndrome (LS). Here, we present a case of a 64-year-old Polish-speaking female in whom an incidental finding of polyposis turned out to be a malignancy. Our patient had a positive family history of colon cancer. The delay in performing an annual colonoscopy with endoscopic polypectomy per AFAP surveillance guidelines was supposedly delayed due to lack of insurance and language barrier. There were no metastases and she was negative for the APC gene mutation. Pathology was significant for moderately differentiated adenocarcinoma with intact mismatch repair protein (MMRP) (expression of