A 73-year-old white male presented to a tertiary center after an initial colonoscopy at an outside hospital showed at least 15 polyps, the largest measuring 2.3 cm. The patient denied any family history of colorectal neoplasia and has undergone several colonoscopies since that time with mucosal resection of numerous polyps throughout the colon. The largest polyp was a 2.3-cm tubular adenoma in the cecum. The severity of his melanosis coli functioned similarly to chromoendoscopy to highlight the location of his polyps (Figure 1). His medication list included aspirin, diltiazem, finasteride, colesevelam, and vitamin C. Upon further questioning, the patient reported taking an herbal laxative called Cape Aloe for the past several years, which is likely responsible for his melanosis coli.
Figure 1. Melanosis coli highlighting (A) a 2.3-cm polyp at the ileocecal valve and (B) a polypoid lesion at the cecum.
Melanosis coli is the dark pigmentation secondary to lipofuscin accumulation within the mucosal macrophages. The most common colonic locations include the rectum and cecum, with a well-known laxative association, particularly anthracene derivatives including aloe, cascara, rhubarb, and senna.1 One case study showed reversal of pigmentation within a year of stopping aloe intake.2 Interestingly, pigment deposition spares neoplastic lesions including adenomas or carcinoma, with current recommendations to remove these nonpigmented areas when possible.3 There was initial concern that long-term use of anthranoid laxatives could potentially increase the risk of malignancy.4 However, a prospective study showed no increased risk of development of colorectal adenoma or carcinoma.5
Author contributions: RM Modi wrote the manuscript and is the article guarantor. H. Hussan edited and approved the manuscript.
Financial disclosure: None to report.
Informed consent was obtained for this case report.
Correspondence: Rohan M. Modi, 395 W 12th Ave, 3rd Floor, Columbus, OH 43210-1267 (Rohan.Modi@osumc.edu).
Received April 24, 2016; Accepted June 9, 2016
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