Pseudomelanosis duodeni: is there a common denominator?

A 76-year-old female patient with a past medical history of diabetes mellitus, stage 3 chronic renal failure and iron deficiency anemia was referred for esophagogastroduodenoscopy (EGD) for evaluation of solid food dysphagia. She had been on oral therapy with ferrous sulfate for several years. Besides a Schatzki's ring the EGD revealed a duodenal mucosa with black-speckled pigmentation. Biopsies were performed and disclosed the deposition of brown (hemosiderin) pigment within macrophages in the lamina propria of normal villi. This endoscopic appearance is called pseudomelanosis duodeni (PD).