Gastric and Duodenal Pseudomelanosis in a Patient With Chronic Kidney Disease and Oral Iron Supplementation

Abstract

A 74 year-old lady has a history of hypertension (HTN), diabetes mellitus (DM), mild chronic kidney disease, coronary artery disease, cerebrovascular accident, osteoarthritis, Iron deficiency anemia and gastroesophageal reflux disease. Her medications include ferrous sulphate and hydralazine. She had an upper GI endoscopy for evaluation of iron deficiency anemia and refractory GERD. Endoscopy showed dark, pigmented, granular appearing mucosa in gastric antrum, lesser curvature of gastric body and duodenal bulb (pseudomelanosis). Pathology from gastric biopsies showed reactive gastropathy and gastric siderosis with deposits of granular, darkly pigmented material showing stromal predominant deposition with presence in macrophages and epithelium. This material stained positive with Prussian blue stain and was negative for Melan-A stain. Pseudomelanosis of stomach and duodenum is associated with various clinical conditions including HTN, DM, chronic kidney disease, gastrointestinal hemorrhage and use of various medications including ferrous sulphate, furosemide, hydralazine, propranolol and hydrochlorothiazide. Differential diagnosis includes hemosiderosis/hemochromatosis, brown bowel syndrome and malignant melanoma, which could be differentiated by using special stains and immunohistochemical markers. Histologically, iron pigments are deposited in lysosomes of macrophages in lamina propria. These pigments are detected by Prussian blue Stain and Fontana-Masson stains of macrophages in the lamina propria. It had been seen mostly in older women similar to our patient. Most cases are asymptomatic, however dyspeptic symptoms have been described occasionally. Long term prognosis and consequences of this condition is unknown. No specific treatment is recommended.Figure: EGD revealed Pseudomelanosis in the stomach.Figure: This material stains positive in areas with a Prussian blue iron immunohistochemical stain and is negative for Melan-A stain.Figure: Deposits of granular, darkly pigmented material displays a nonspecific stromal and macrophage predominant pattern.