S6430 Pseudomelanosis of the Stomach: A Rare Gastric Presentation of a Common Duodenal Finding

Introduction: Pseudomelanosis is a rare endoscopic finding, most commonly involving the duodenum, and characterized by dark pigmentation of the mucosa due to deposition of substances such as iron, melanin, or lipofuscin. Gastric involvement is exceedingly rare, with few cases reported. We present a unique case of gastric pseudomelanosis in a patient whose upper endoscopy 1 year earlier had shown normal mucosa. Case Description/Methods: A 78-year-old woman with end-stage renal disease, coronary artery disease, type 2 diabetes, and chronic obstructive pulmonary disease presented with shortness of breath and dysphagia. Her medications included carvedilol, hydralazine, and ferrous sulfate. One year prior, she was found to have normocytic normochromic anemia (Hgb 6.5 g/dL) and underwent esophagogastroduodenoscopy (EGD), which showed normal mucosa. She received blood transfusions but continued to take iron supplements daily for the following year. On repeat presentation, she had dysphagia and EGD revealed diffuse mild gastritis with dark mucosal pigmentation in the stomach and duodenum. Gastric biopsy stained with Perl’s iron confirmed crystalline iron deposits, consistent with pseudomelanosis. Discussion: Pseudomelanosis of the stomach is an uncommon, benign condition often associated with chronic renal failure, diabetes, aging, and prolonged iron supplementation. Its pathogenesis may involve impaired mucosal absorption of pigment-forming substances. Recognition of this entity is important to avoid misdiagnosis and unnecessary interventions. Endoscopic findings may mimic serious pathology such as metastatic melanoma; however, biopsy with iron staining is diagnostic. This case highlights the evolving nature of mucosal pigmentation and the need for histological confirmation in atypical findings.