An otherwise healthy 57-year-old woman underwent routine follow-up colonoscopy after colonoscopic polypectomy 6 years previously. She was found to have a healthy colon, but her rectum showed a circumferential dense collection of polyps (Figure 1). Multiple biopsy specimens of the polyps were obtained. Pathologic examination demonstrated multiple serrated adenomas. The patient reported no family history of colon cancer, and she had no biologic children. On rectal examination, she had multiple palpable polyps extending to the dentate line.
She underwent rigid sigmoidoscopy followed by low anterior resection with coloanal J pouch reconstruction. Final pathologic examination demonstrated the carpet of polyps; some polyps were larger than 1 cm, but all were negative for carcinoma (Figure 2).
A. Familial adenomatous polyposis
B. Hereditary nonpolyposis colorectal cancer syndrome
C. Serrated adenomatous polyposis
D. Hereditary mixed polyposis syndrome