Clinical masks of autoimmune gastritis: clinical manifestations, complications, and contemporary diagnostic approaches (a case series)

Autoimmune gastritis (AIG) is the second most common cause of chronic atrophic gastritis after Helicobacter pylori. The disease is characterized by progressive immune-mediated destruction of gastric parietal cells, resulting in mucosal atrophy, impaired acid secretion, and a range of systemic complications. A paucisymptomatic course in the early stages and the heterogeneity of clinical presentations often lead to delayed diagnosis. Objective. To illustrate the clinical heterogeneity of autoimmune gastritis, its major extra-gastric manifestations and complications, and contemporary diagnostic opportunities using representative clinical cases. Case series. Two cases of AIG are presented. In the first case, AIG manifested over a prolonged period as iron-deficiency anemia and dyspeptic symptoms in a female patient with autoimmune thyroiditis and a family history of gastric cancer. In the second case, delayed recognition of AIG in an elderly male patient was associated with vitamin B12-deficiency anemia and gastric adenocarcinoma detected at an early stage and treated with curative endoscopic resection. In both cases, the diagnosis was confirmed based on endoscopic, histopathological, and serological findings. Conclusion. Autoimmune gastritis often follows a subclinical course and presents with a broad spectrum of manifestations, including anemia of different etiologies and oncologic complications. Timely diagnosis of AIG, regular follow-up, and a multidisciplinary approach are essential to prevent severe complications and improve patient outcomes.