Pseudomelanosis Duodeni and Duodenal Polyp.

A 68-year-old man presented with obscure gastrointestinal bleeding. A duodenal polyp was incidentally identified in the background of black pigmentations on double balloon enteroscopy (Picture 1, 2). Biopsies of the pigmentations revealed crystalline material deposits in the lamina propria of the villi that stained positive with Prussian Blue. Therefore, the diagnosis of pseudomelanosis duodeni was confirmed (Picture 3). Interestingly, this polyp showed no uptake of pigmentation. Endoscopic mucosal resection of this polyp revealed Brunner's gland hyperplasia along with gastric foveolar metaplasia with focal low-grade dysplasia. There was only minimal iron deposition in this polyp (Picture 4). Pseudomelanosis duodeni is an uncommon condition which is known to be associated with hypertension, diabetes mellitus, hemochromatosis, chronic kidney disease, and gastrointestinal bleeding (1, 2). This is a rare description of a duodenal polyp in the context of pseudomelanosis duodeni that showed similar endoscopic findings to those typically seen in colonic polyps in melanosis coli.

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The authors state that they have no Conflict of Interest (COI).