Collagenous gastritis in pediatric patients

RATIONALE: Collagenous gastritis (CG) is a rare disorder of unclear etiology. We report two pediatric cases and provide a comprehensive review of the literature. PATIENT CONCERNS: Case 1 was a 7-year-6-month-old girl presenting with severe iron-deficiency anemia and pallor. Esophagogastroduodenoscopy (EGD) revealed fragile, bleeding-prone gastric mucosa with diffuse inflammatory changes. Histopathological examination of gastric biopsy specimens demonstrated subepithelial collagen deposition with positive Masson's trichrome staining, confirming the diagnosis of CG. Case 2 was a 12-year-1-month-old girl presenting with recurrent anemia and fatigue. EGD showed thickened gastric folds and pale mucosa. Gastric biopsy demonstrated collagen-like fiber deposition beneath the surface epithelium with positive Masson's trichrome staining. DIAGNOSES: Both patients were diagnosed with CG based on characteristic histopathological findings, including subepithelial collagen deposition and positive Masson's trichrome staining. INTERVENTIONS: Both patients received supportive treatment, including gastric mucosal protection and iron supplementation for anemia. OUTCOMES: During follow-up, both patients showed improvement in anemia without disease progression. No recurrence of anemia was observed in Case 1 during one year of follow-up. In Case 2, anemia-related symptoms improved after treatment, and the patient remained clinically stable at 8 months of follow-up. LESSONS: Pediatric CG commonly presents with abdominal pain and iron-deficiency anemia, whereas endoscopic findings may vary among different gastric regions. Histopathological confirmation showing subepithelial collagen bands with positive Masson's trichrome staining is essential for diagnosis. CG should be considered in children with unexplained iron-deficiency anemia, especially when accompanied by gastrointestinal symptoms. Early recognition and appropriate gastric biopsy during EGD may help prevent delayed diagnosis.