Magnifying endoscopy with indigo carmine contrast for the differential diagnosis of adenomatous and hyperplastic colonic polyps

There are no reliable endoscopic criteria to discriminate hyperplastic from adenomatous polyp. Mucosal biopsy remains the gold standard for the diagnosis of colonic polyps. In this study, we use magnifying endoscopy with indigo carmine dye contrast to differentiate these two types of polyp. Colonoscopic examinations were performed in 30 patients to analyze a total 30 polyps. Indigo carmine (1%) was directly sprayed on the surface of the polyps, and the magnifying endoscope (Olympus CF240Zl) was then used to observe their villi and crypts (pit pattern). The pit pattern analysis was according to Kudo's classifications. The polyps were then polypectomized or biopsy for pathological diagnosis. There were two polyps with type I; six with type II, two with type IIIs; four with type IIIL; and fourteen with type IV; and two with type V pit pattern. The pit pattern has good correlation with its respective histology. We therefore conclude that magnifying endoscopy with indigo carmine contrast provides detailed morphological study of colorectal polyps that helps to distinguish non-neoplastic from neoplastic polyps. This technique may decrease the need for biopsy and polypectomy for non-neoplastic polys, and ultimately lower medical expense and avoid the unwanted complications associated with colonoscopic examination.