Rare Concurrent Findings With Collagenous Gastroduodenitis in a Pediatric Patient.

Collagenous gastritis is a rare type of gastritis characterized by thickened subepithelial collagen and chronic inflammatory infiltrate. We describe the unique presentation of a previously healthy 13-year-old girl, who presented with severe fatigue and exertional dyspnea. The gastric and duodenal histologic features were consistent with collagenous sprue, collagenous gastritis, and chronic atrophic gastritis. To the best of our knowledge, the simultaneous presentation of these entities is highly uncommon in children, underscoring the importance of understanding its pathogenesis.