Walter Reed National Military Medical Center Bethesda, MD, United States
Luca Micci, MD1, Tudor Oroian, MD2, Mark N. Damiano, MD3 1Walter Reed National Military Medical Center, Tamarac, FL; 2Walter Reed National Military Medical Center, Bethesda, MD; 3Walter Reed National Military Medical Center, Washington, DC
Introduction: Melanosis coli is a common condition best characterized by a black or brown discoloration of the colonic mucosa secondary to lipofuscin deposits. Chronic anthranoid laxatives have been historically linked as a main culprit by causing active cell death and apoptosis in the lining of the colon, thereby causing the dark pigmentation. In this population of patients, the association with development of colorectal polyps is uncertain. In a case-control retrospective study, melanosis coli was found to have a higher incidence and number of colonic polyps (7.3% vs 0.5% in the control; p < 0.001) along with higher incidence of low grade adenomas as well. This increased rate of incidence may also be confounded by an increased rate of detection. A retrospective single-center study looked at a cohort of 718 patients with melanosis on colonoscopy and 2154 controls over a 15 year period found poly detection rates to be 11.6% higher when compared to control (33.4% and 21.8% detection in melanosis and control patients respectively).
Case Description/Methods: Our 56 year old patient had a colonoscopy done for average risk cancer screening. Colonoscopy demonstrated significant melanosis coli throughout the entire examined colon (Image 1). The mucosal surface was initially difficult to examine and visualize adequately, however, upon withdrawal, very clearly demarcated areas of normal-colored mucosa stood out from the dark background. Three tubular adenomas were found during examination (measuring 3mm, 4mm, and 4mm) in the cecum, ascending colon, and transverse colon respectively. No signs of dysplasia were noted on histopathology.
Discussion: Few cases have been documented examining how melanosis coli may affect rate of detection of adenomas within the colon. Our findings add to the scarce cases which consider severe melanosis coli as a factor that may enhance polyp detection on colonoscopy secondary to the contrasted background and the unpigmented polyps. Further data is needed to elucidate this association between melanosis coli and a possible increased risk of neoplasm versus a confounding enhanced rate of polyp detection secondary to the contrasted background.
Figure: Colonic tubular adenoma starkly contrasting with background of melanosis coli.
Disclosures: Luca Micci indicated no relevant financial relationships. Tudor Oroian indicated no relevant financial relationships. Mark Damiano indicated no relevant financial relationships.
Luca Micci, MD1, Tudor Oroian, MD2, Mark N. Damiano, MD3. P0283 - A Case of Severe Melanosis Coli and Consideration of Implications in Adenoma Detection, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.