[Pediatric collagenous gastritis: a rare etiology of iron-deficiency anemia.].

Collagenous gastritis is a rare pediatric disease characterized by chronic gastritis with superficial, irregular mucosal involvement, focal atrophy of the gastric glands, an inflammatory infiltrate predominantly composed of lymphocytes and plasma cells, and areas of epithelial erosion. Focal collagen deposition in the subepithelial region of the lamina propria is a hallmark feature. Gastric epithelial erosions can cause hematemesis and, more generally, occult gastrointestinal bleeding, leading to chronic iron-deficiency anemia. Currently, there are no established management guidelines, and data on long-term follow-up are lacking. We report a clinical case of collagenous gastritis, emphasizing its features and therapeutic approach.