IgG4-related Disease Manifesting as Gastroduodenal Ulcer Diagnosed by an Endoscopic Biopsy.

A 26-year-old man was admitted to our hospital due to upper abdominal pain. He had previously been diagnosed with gastroduodenal ulcer at 23 and 25 years old and had been treated with proton-pump inhibitors. Endoscopic hemostasis and a biopsy were performed on the hemorrhagic gastroduodenal ulcers. Laboratory and pathologic examinations demonstrated elevated serum IgG4 levels and the infiltration of IgG4-positive plasma cells into the gastroduodenal tissues. Based on the clinicopathologic findings and after excluding other causes, he was diagnosed with IgG4-related gastroduodenal ulcer. We herein report a rare case of IgG4-related disease manifesting as a gastroduodenal ulcer diagnosed by an endoscopic biopsy.