A case of collagenous gastritis resembling nodular gastritis in endoscopic appearance

A 25-year-old Japanese female was referred to our clinic for the investigation of moderate iron-deficiency anemia and epigastralgia. Endoscopic examination showed diffuse mucosal nodules in the gastric body resembling nodular gastritis, but this pattern was not observed in the antrum. Histology of the gastric biopsies taken from the gastric body showed mild atrophic mucosa with chronic active inflammation. Some of the biopsy specimens showed deposition of patchy, band-like subepithelial collagen. Four years later, the patient showed no clinical symptoms and signs. A follow-up endoscopic examination showed similar findings, which mimicked pseudopolyposis or a cobblestone-like appearance. The biopsy specimens from the depressed mucosa between the nodules revealed a thickened subepithelial collagen band with no improvement, which led to a diagnosis of collagenous gastritis. Treatment with oral administration of proton-pump inhibitors and histamine-2-receptor antagonists had proved ineffective. To make a correct diagnosis of collagenous gastritis, we should determine the characteristic endoscopic findings and take biopsies from the depressed mucosa between the nodules.