Introduction: Pseudomelanosis duodeni (PD) is a rare incidental finding characterized by brownish black pigmentation seen primarily in the first and second portions of the duodenum. The exact cause is unknown but it is associated with certain medications and chronic medical conditions. Here we present a case to help gastroenterologists recognize this rare endoscopic finding.
Case Description/Methods: A 49 year-old man with a past medical history of GERD, obesity, obstructive sleep apnea, type 2 diabetes and atrial fibrillation was referred for evaluation of rectal bleeding and iron deficiency anemia. His medications included iron supplementation, amlodipine, aspirin, atorvastatin, carvedilol, furosemide, and hydralazine. The cause of the patients rectal bleeding was determined to be from hemorrhoids found during colonoscopy. Esophagogastroduodenoscopy demonstrated diffuse mucosal changes characterized by speckled black pigmentation extending along the villi (FIGURE 1). Biopsies were taken and showed benign black pigmented macrophages in the lamina propria.
Discussion: Pseudomelanosis duodeni is a rare finding of unknown etiology. It is associated with chronic medical conditions including iron deficiency anemia, hypertension, diabetes, chronic kidney disease and common medications such as ferrous sulfate, hydralazine, propranolol, hydrochlorothiazide and furosemide. Despite the association with these common conditions and medications, PD remains a rare endoscopic finding. Why certain patients develop this finding is unknown. Interestingly, there is no association with anthraquinones as seen in pseudomelanosis coli. Histology typically shows black granular pigment inside macrophages within the tips of the villi. Although the endoscopic findings are striking, the condition has no clinical consequence and requires no treatment.
