Melanosis coli: a contrast effect or an oncogenic effect? A large scale retrospective cohort study International Journal of Colorectal Disease Springer Nature Link Stained Colon by "David M. Martin, Md Science Photo Library" This is a very rare case of metastatic oral mucosal melanoma to the colon with an unusual presentation mimicking melanosis coli. The colonoscopy findings show no mass effect but multiple hyperpigmented lesions SciELO Brasil Prevalence of hepatitis C virus genotypes in the State of Par, Brazil Prevalence of hepatitis C virus genotypes in the State of Par, Brazil Experimental and Therapeutic Medicine Hepatitis C reactivation in patients with chronic infection with genotypes 1b and 2c: a retrospective cohort study of 206 untreated patients Gut