The use of acetic acid in the characterization of polyps, produces a homogeneous white staining in sessile serrated adenomas, but not in tubular or tubulo-villous adenomas, a simple approach to predict polyp histopathology.

To determine the diagnostic accuracy of the use of acetic acid on tubular and serrated adenomas, during colonoscopy, a prospective diagnostic accuracy study was designed, taking as gold standard the pathological anatomy of the resected polyps.

Polyps found during a colonoscopy with suspicion of sessile serrated adenomas or tubular/tubulo villous will be included.

In our experience tubular or tubulovillous adenomas with acetic acid have the same behavior as normal colonic mucosa. When sprayed with acetic acid they stain white, as well as the surrounding mucosa, but with a subsequent rapid loss of the effect. In contrast, serrated adenomas maintain an "aceto-whitening" reaction even though the surrounding normal mucosa loses staining.

The objectives are to determine the sensitivity and specificity, positive and negative probability coefficients of the positive or negative aceto-whitening reaction on serrated adenomas and tubular-tubulo-villous adenomas.

To determine the diagnostic accuracy of the use of acetic acid on tubular, tubulo-villous and serrated adenomas a prospective diagnostic accuracy study was designed considering the gold standard as the pathological anatomy of resected polyps.

As independent variables the presence or absence of aceto-whitening reaction after staining and the diagnostic impression of the endoscopist without acetic acid are considered. The presence or not of the aceto-whitening reaction will be evaluated, understanding it as the persistence of white staining of the polyp at one minute or three minutes, standing out from the surrounding mucosa.

In case of positive staining it will be considered homogeneous if the staining is uniform on the surface of the polyp or heterogeneous if it is done irregularly.

Place: German Hospital, endoscopy unit.

Data analysis: the data collected in double-entry tables will be captured to obtain the same sensitivity, specificity and positive or negative probability coefficients.

Sample size: 100 polyps.

Estimated duration: 1 month

Inclusion Criteria:

• Patients with colonic polyps> 5mm with suspicion of tubular, tubulovillious or serrated adenomas, found during a videoolonoscopy.

Exclusion Criteria:

• Known acetic acid allergy
• Known or documented history of adenomatous or serrated polyposis
• Patients with inflammatory bowel disease