Diminutive polyps: histopathology, spatial distribution, and clinical significance.

This retrospective study of 329 diminutive colon polyps revealed that 49.2% of the polyps were neoplastic, whereas 49.9% were nonneoplastic. 36.8% of the polyps were metaplastic, and 0.9% had mixed metaplastic and adenomatous components. The metaplastic polyps had a predominance in the distal portion of the large bowel, with 76.9% being located distal from the splenic flexure and 52.9% being located in the rectosigmoid area. Neoplastic polyps were distributed throughout the colon, with 65.4% located from the splenic flexure distally and 34.5% located proximal to the splenic flexure. These findings suggest that a much larger proportion of diminutive polyps are neoplastic and therefore at risk to progress to carcinoma than previously considered.