Detection of colorectal adenomas by routine chromoendoscopy with indigocarmine.
OBJECTIVE
Nonpolypoid adenomas, which can be important precursors of colorectal cancers, are difficult to find during routine colonoscopy. The aim of this study was to evaluate the usefulness of routine chromoendoscopy in Korea, where the incidence of colorectal cancer is low compared with western countries.


METHODS
Colonoscopy with chromoendoscopy was performed in 74 consecutive patients (48 men, 26 women; mean age 53.0 yr). After a careful examination of the whole colon, a defined segment of the sigmoid colon and rectum (0-30 cm from the anal verge) was stained with 20 ml of 0.2% indigocarmine solution with a spraying catheter. Nonpolypoid lesions were classified as flat or depressed types. Biopsies were taken from all lesions detected before or after staining with indigocarmine.


RESULTS
Indications for colonoscopy included routine check-up (21 patients), diarrhea or loose stool (14 patients), abdominal pain (12 patients), constipation (7 patients), bleeding (6 patients), and others (14 patients). Before staining, 58 lesions were found in 30 patients (43.2%). Histology showed tubular adenoma in 41 lesions, hyperplastic or inflammatory changes in 14 lesions, adenocarcinoma in 2 lesions, and villous adenoma in 1 lesion. After indigocarmine staining for normal-looking distal 30 cm colorectal mucosa, 176 lesions were found in 46 patients (62.2%). Histologically, 158 lesions were hyperplastic or inflammatory in nature, and 17 lesions (from 11 patients) were tubular adenomas. There was one serrated adenoma. Eighteen adenomas seen only after spraying indigocarmine were 2.6 +/- 0.6 mm in diameter, and all of them were classified as flat adenomas. There was no depressed-type adenoma. No adenoma with high grade dysplasia, villous histology, or cancer was found after staining. Presence of macroscopic adenomatous lesions or carcinoma before staining could not predict the existence of adenoma after staining.


CONCLUSIONS
In a large proportion of patients, flat or depressed adenomas could be found after spraying indigocarmine for normal-looking colorectal mucosa in Korea. The clinical significance of these diminutive adenomas that can be found only after spraying contrast agent needs to be further investigated.
Lee
Jun Haeng
JH
Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Kim
Jeong Wook
JW
Cho
Yong Kyun
YK
Sohn
Chong Il
CI
Jeon
Woo Kyu
WK
Kim
Byung Ik
BI
Cho
Eun Yoon
EY
D000236:Adenoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D004396:Coloring Agents; D005260:Female; D006801:Humans; D007203:Indigo Carmine; D008297:Male; D008875:Middle Aged
D004396:Coloring Agents; D007203:Indigo Carmine