A Graves' Disease Patient Diagnosed as Autoimmune Gastritis with Helicobacter pylori Infection

Autoimmune gastritis (AIG) is a type of atrophic gastritis characterized by destruction of parietal cells in the gastric fundus and body. These changes may be attributable to immune-mediated chronic inflammatory responses. AIG is characterized by extensive atrophy of the gastric body; therefore, endoscopic findings offer useful diagnostic clues. AIG is diagnosed based on serological and histopathological evaluation of endoscopic biopsy specimens; however, this condition may be accompanied by autoimmune diseases including autoimmune thyroid disease (ATD), and the opposite can be suspected. Diagnostic delays and misdiagnosis are common in patients with AIG owing to the nonspecific clinical presentation and accompanying autoimmune diseases. Additionally, confirmation of AIG based on serological atrophy or endoscopic findings is challenging in cases of active Helicobacter pylori (H. pylori) infection. We report a case of Graves’ disease (an ATD) in a patient diagnosed with AIG and concomitant H. pylori-induced gastritis based on the rapid urease and serological test results and endoscopic biopsy findings.