Risk of Colorectal Polyps in Patients With Skin Lesions, a Prospective Case-Control Pilot Study Jose M. Mella, Raquel Gonzalez, Carolina Fischer, Guillermo Nicolas Panigadi, Lisandro Pereyra, Pablo Luna, Kamelia Losada, Veronica L. Llorca, Margarita Larralde, Sandra Lencinas, Mario A. Medrano, Silvia C. Pedreira, Daniel G. Cimmino, Luis A. Boerr Hospital Aleman, Buenos Aires, Argentina Introduction: Skin lesions such as acrochordons (skin tags), seborrhoeic keratoses, and lentigines have been proposed as markers for adenomatous polyps of the colon, but controversy remains. Aim: To assess the risk of colorectal polyps, adenomas and advanced neoplastic lesions (ANL: villous component 75%, size 10 mm, or high grade dysplasia) in patients with acrochordons, seborrhoeic keratoses, and lentigines in a private community hospital in Argentina. Materials and methods. During February 2010, all patients who underwent a colonoscopy were prospectively assessed by a dermatologist, before the endoscopy procedure, to determine the presence of these skin lesions. Those with previous colonoscopies, incomplete colonoscopies, inadequate intestinal cleansing, or colonic surgeries were excluded. Endoscopists were blind to the dermatologic findings. A case-control study was carried out. Patients with skin lesions were defined as “cases”, and those without them as “controls”. The risk of presenting the mentioned colonic lesions was analyzed, measured in odds ratio (OR) and its corresponding confidence intervals 95% (CI). Results: 42 patients were analyzed; the media age was 59 12 years old (range 29-83), 71% were women. Skin tags were found in 23 patients (55%), seborrhoeic keratoses in 20 patients (48%), and lentigines in 10 patients (24%). Colonic polyps were detected in 21 patients (50%); 14 patients (33%) had adenomas and 7 patients (17%) had ANL. There were no significant differences in the prevalence of adenomatous lesions, neither ANL nor colorectal cancer in those patients with skin tags (OR 1.15 CI 0.33-4.07, OR 1.12 CI 0.24-5.19, OR 2.7 CI 0.34-20, respectively), in those with seborrhoeic keratoses (OR 0.75 CI 0.212.65, OR 3.33 CI 0.64-16.88, OR 3.70, CI 0.47-27.8, respectively), and in those with lentigines (OR 0.16 CI 0.02-1.15, OR 0.48 CI 0.07-3.63, p 0.56, respectively) comparing with those without them. Conclusion: The results of this preliminary study did not show a higher risk of colorectal adenomas or ANL in patients with these lesions. The mere presence of these skin lesions would not be used as an indication for screening colonoscopy.