Pseudomelanosis Duodeni: An Unusual Finding From Upper Gastrointestinal Endoscopy

A 54-year-old man underwent upper gastrointestinal endoscopy during a physical exam. Significant features of his medical history included 10 years of hypertension that had been controlled with hydralazine and enalapril therapies. The results of his physical examination and laboratory tests were normal. Endoscopy revealed a normal esophagus and stomach, but upper gastrointestinal endoscopy showed discrete black pigmentation from the duodenal bulb to the second portion (Figure A). Analysis of biopsy samples from the duodenum revealed that a black pigment had accumulated in macrophages of the lamina propria (Figure B). The diagnosis, on the basis of these results, was pseudomelanosis duodeni.

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Pseudomelanosis duodeni1, 2 is a rare condition. To an endoscopist, it indicates flat, discrete, black, or brown pigment spots of proximal duodenal mucosa. Its etiology is unknown, but it has been associated with hypertension and chronic renal failure. Certain antihypertensive agents, including hydralazine, propranolol, furosemide, and hydrochlorothiazide, have been implicated in the condition. Electron probe x-ray analysis has indicated that the pigment contains ferrous sulfide. Pseudomelanosis duodeni is considered to be a benign lesion that has not been associated with duodenal malignancy.