6976 4 cases of serrated adenoma accompanying another colon cancer.

Abstract

proposed the concept, serrated adenomas have drawn attention of many colonoscopists and pathologists. It has been thought that serrated adenomas have a tendency to become malignant compared with tubular adenomas. We experienced 22 cases of serrated adenomas in recent 3 years, but only 1 serrated adenoma got malignant. On the other hand, interestingly, in 4 cases out of 22, another colon cancer was found. In 3 cases serrated adenoma and another cancer were found simultaneously. In these cases, another cancer was early colon cancer. In 1 case, advanced cancer was detected 3 years after the polypectomy of serrated adenoma. Case 1 : 45 years old, female Polypoid serrated adenoma (12mm in diameter) in ascending colon and polypoid tubulovillous adenoma with focal malignancy (18mm in diameter) in sigmoid colon were found simultaneously. Both lesions were removed by polypectomy. Case 2 : 77 years old, male Polypoid serrated adenoma (6mm in diameter) in sigmoid colon and polypoid tubulovillous adenoma with focal malignancy (10mm in diameter) in sigmoid colon were found simultaneously. Both lesions were removed by polypectomy. Case 3: 70 years old, female Polypoid serrated adenoma (14mm in diameter) in ascending colon, polypoid serrated adenoma (8mm in diameter) in sigmoid colon, and flat adenocarcinoma with minimal submucosal involvement (8mm in diameter) in ascending colon were found simultaneously. All lesions were removed by endoscopically. Case 4 : 52 years old, male Polypoid serrated adenoma (12mm in diameter) in sigmoid colon was removed by polypectomy. After 3 years, advanced adenocarcinoma in transverse colon was detected and resected surgically. 18.2% (4 cases out of 22) of serrated adenomas accompanied another colon cancer. This rate is surely higher than that of tubular adenomas. Patients who have serrated adenomas might be the high risk group of colorectal carcinoma. Therefore, we think, they should be followed very carefully and frequently not to overlook another colorectal carcinoma.