The appearance of melanosis coli during colonoscopy is largely due to pigment deposition in the colonic mucosa. The pigmentation sparing sign on detected polyps has been defined as a lesion that looks pale compared to the surrounding brownish colonic mucosa. Our previous observation suggested that the pigmentation sparing sign could be a diagnostic marker of adenoma on melanosis coli. The aim of this study wants to prove this previous concept with a correlation between endoscopic and histological features from a case series. A consecutive series of patients scheduled for colonoscopy for cancer screening and diagnosed with melanosis coli and polyps during 2014 were retrospectively evaluated. We collected data including sex, age, and the size and location of polyps. For patients with multiple polyps, all polyps were evaluated histologically. During the study period, 35 polyps in 16 patients (5 males and 11 females; mean age 59.1 years [range, 32‐91]) who were diagnosed with colonic polyps on melanosis coli were enrolled. These included 21 polyps with pathologically confirmed adenoma and 14 hyperplastic polyps. The adenomas had an average diameter of 3.9 mm (range, 2‐15 mm) and the hyperplastic polyps had a mean diameter of 2.9 mm (range, 2‐8 mm). The use of the pigmentation sparing sign for predicting adenoma had a sensitivity of 95.2%, a specificity of 78.6%, a positive predictive value of 87.0%, and a negative predictive value of 91.7%. The overall accuracy for predicting melanosis coli with the pigmentation sparing sign was 88.6%. This study suggests the pigmentation sparing sign could be a good diagnostic marker of adenoma on melanosis coli. Furthermore, upon detection of such a lesion, the excision and further histopathologic analysis of these polyps may be facilitated.

No abstract

No abstract