Pathologic Review of the Rectal Villous Adenoma

Lim, Kyung Uk; Shin, Young Do; Lee, Seok Hwan; Kee, Kee Hyung

Abstract

Neoplastic polyps of colon are one of the most risky factors for colorectal cancer. Particularly villous adenomas have more malignant potential than other neoplastic polyps. The preoperative detection of malignant change in villous adenoma is very important to determine treatment modality of patients. We conducted that total twenty-four cases of villous adenoma who were diagnosed and treated at our institution between January 1990 and December 1995 were reviewed retrospectively. The peak incidence of age was 7th decades. And male to female ratio was 2 : 1. Size of the adenoma ranged from 1.2 to 10.7 cm with a mean diameter of 3.9 cm. Five cases(20.8%) were between 1 and 2 cm, 10(41.7%) between 2 and 4 cm, and 9(31.5%) greater than or equal to 4 cm. Location of the adenoma were 10 cases(41.7%) in upper rectum, 8(33.3%) in rectosigmoid, and 6(25.0%) in lower rectum respectively. Pathologic examination of the resected specimen were diagnosed 9(37.5%) as benign villous adenomas, 10(41.7%) as in situ carcinoma, and 5(20.8%) as invasive carcinoma. The diagnostic accuracy to detect in situ carcinoma or invasive carcinoma was endoscopic examination in 66.7 percent and digital examination in 86.7 percent. The grade of in situ carcinoma had not significantly relationship with the size of the adenoma on our study. However, invasive carcinoma was significantly related to adenoma size(P<0.05) as following results zero percent between 1 and 2 cm, 20 percent between 2 and 4 cm, and 33.3 percent greater than or equal to 4 cm. In conclusion, the larger villous adenoma has higher malignant potential, especially greater than or equal to 4 cm in size. Added, the clinical impression of the malignancy on digital examination can be more accurate than preoperative endoscopic examination on our study.