Significance of an Early Diagnosis of Autoimmune Gastritis in Nonelderly Patients with Type 1 Diabetes Mellitus and Autoimmune Thyroid Disease: A Case Report.

A 45-year-old woman with Basedow's disease, who was later diagnosed with slowly progressive type 1 diabetes mellitus (SPIDDM), developed iron deficiency anemia. Despite normal vitamin B12 levels, the endoscopic findings of the residual fundic glands and severe atrophy predominantly in the body of the stomach and fundus, along with serological tests, confirmed a diagnosis of autoimmune gastritis (AIG). This case highlights the significance of an early AIG diagnosis in non-elderly patients with type 1 diabetes mellitus (T1DM) and autoimmune thyroid disease (AITD) because of the risk of developing pernicious anemia and gastric neoplasms.