An Enigmatic Case of Vanishing Pounds

Collagenous gastritis is a rare disorder of abnormal subepithelial collagen deposition that remains poorly understood. It is characteristically associated with > 10 μm of subepithelial collagen with evidence of an inflammatory response in the lamina propria. We report a rare dual diagnosis of collagenous gastritis and collagenous duodenitis in an elderly man who previously underwent gastric antrum biopsy without identification of subepithelial collagen deposition.