Development, Disappearance, and Clinical Course of Melanosis Coli: Sex Differences in Progression of Severity
Abstract Background Melanosis coli (MC) is an acquired colorectal disorder visualized as colonic mucosa pigmentation. Disease severity is confirmed based on MC depth, shape, and coloration, although the clinical course is not fully understood. This study sought to clarify characteristics of MC development and disappearance and to demonstrate its clinical course and severity. Contributors to progression of MC grade were also explored. Methods To investigate the patient and clinical features of developing and disappearing MC, this study reviewed colonoscopy cases at a single institution over a 10-year period. The clinical course of MC grade was evaluated to explore the predictive factors of progressive MC. Kaplan–Meier analysis was used to determine the probability of disease progression, and the log-rank test was used to calculate equality of the clinical course. Results Of all MC cases, 17 developing and 11 disappearing cases were detected. Anthranoid laxative use was a key factor: 29.4% of developing cases used this agent before initial diagnosis of MC, whereas 27.2% of disappearing cases discontinued anthranoids before detection of MC disappearance. Among 70 grade I cases, progression to grade II occurred in 16 cases during mean follow-up of 3.67 ± 2.1 years. Male sex was more frequent in progressive than stable cases, and probability of progression was higher for male versus female cases. Conclusions An association between anthranoid administration and MC presence was detected; a sex difference in the clinical course was confirmed; and mild MC was found to progress in severity over 5 years.