Pseudomelanosis Duodeni: A Benign Pigmentation Or A Precancerous Condition?

Presence of black or brownish spotty pigmentation in mucosal wall of duodenum evident on endoscopy is called pseudomelanosis duodeni (PMD) or melanosis duodeni. Our aim is to present a case of a patient with iron deficiency anemia who had an upper endoscopy and was found to have diffuse pigmentation in duodenum. A 80 year old female with history of hypertension, chronic kidney disease stage 4, iron deficiency anemia who presented for evaluation of anemia. She complained of having dark colored stool for being on iron supplements, but no overt gastrointestinal bleeding. Physical examination was unremarkable. Her laboratory results showed hemoglobin of 11.1 g/dl, hematocrit of 34.6, BUN of 30, creatinine of 2.05. She underwent an EGD and colonoscopy. EGD showed black speckled pigmentation of the duodenal mucosa (Figure 1). Duodenal biopsies showed hemosiderin deposition in the lamina propria of the duodenum, consistent with a diagnosis of pseudomelanosis duodeni. Her colonoscopy was unremarkable. She also underwent capsule endoscopy that showed the pigmentation in the duodenum, with normal appearing remaining small bowel mucosa. PMD is the rare endoscopic appearance of black speckled pigmentation of the duodenum commonly seen in females in the sixth and seventh decades of life. Duodenum is the most common extra colonic gastrointestinal site for pseudomelanosis. While melanosis coli is secondary to accumulation of lipofuscin in the macrophages of the lamina propria, the predominant pigments deposited in PMD are iron sulfide and hemosiderin. The pathogenesis is unclear, it could be secondary to iron deposition as a result of intra-mucosal hemorrhage or impaired iron transport after iron supplementation. Pseudomelanosis duodeni is associated with chronic renal failure, chronic heart failure, gastrointestinal bleeding, hypertension, diabetes mellitus, and the use of certain drugs, such as ferrous sulfate, methyldopa, hydralazine, thiazide, propranolol, digoxin and furosemide. There is no known association with use of laxatives. In conclusion, pseudomelanosis duodeni has unclear diagnostic and prognostic significance and long-term clinical impact of these depositions remains unclear. There is no specific treatment or follow up protocol. Dark mucosal appearance on endoscopy is uncommon and can be a diagnostic challenge for physicians.Figure: Speckled dark pigmentation of mucosa of duodenal bulb.