USING OF ACETIC ACID CHROMOENDOSCOPY FOR THE DIAGNOSIS OF SERRATED COLON POLYPS

Aims To increase the efficiency of endoscopic diagnosis of serrated colon polyps during colonoscopy

Methods 71 polyps were detected in 57 patients in all parts of the colon: 27(38%) – < 5 mm; 36(50,7%)- 6-10 mm; 8(11,3%) – > 10 mm. The macroscopic type was 0-IIа −50(70,2%), 0-Is −21 (29,5). During colonoscopy, 1.5%-acetic acid, 5 ml, was sprayed onto the identified polyps. Mucosa was observed endoscopically for 2 minutes. Then lesions were removed and sent for pathology examination.

Results Use of acetic acid leads to fast acetowhitening reaction of lesions and surrounding mucosa. 2 groups were distinguished: 1) Loss of acetowhitening (LAW) of lesions occurs earlier than LAW of surrounding mucosa. 2) LAW of lesions occurs later than LAW of surrounding mucosa. Group 1 includes 29(40,8%) polyps, 89,6% of which were non-serrated: 21(72,4%) – tubular adenoma; 5(17,2%)- tubular-villous adenoma, one of which had high-grade dysplasia. Only 3(10,3%) polyps were serrated – hyperplastic polyps. Group 2 includes 42 (59,2%) polyps, 97,6% of which were serrated: 27(64,3%) – hyperplastic polyp; 13(30,9%) – sessile serrated adenoma, including one with low-grade dysplasia, 1(2,4%) – traditional serrated adenoma. Only 1(2,4%) polyp was non-serrated – tubular adenoma. This suggests that the LAW of serrated polyps is delayed compared to the LAW of the surrounding mucosa. On the contrary, LAW of non-serrated polyps occurs faster than LAW of surrounding mucosa. LAW of 4(5,6%) polyps was atypical; the reason for this reaction requires further investigation.

Conclusions Use of acetic acid can be used as a diagnostic method to determine the serrated polyps during colonoscopy in real time.