Case Report: A rare case of multiple gastrointestinal autoimmune disorders mimicking autoimmune polyglandular syndrome type 3B.

Autoimmune polyglandular syndrome type 3 (APS-3) encompasses autoimmune thyroid disease and other autoimmune disorders. APS-3B involving gastrointestinal autoimmune diseases. In this case, due to the coexistence of multiple autoimmune diseases including ulcerative colitis (UC), autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and hypothyroidism after papillary thyroid carcinoma surgery and iron deficiency anemia, we diagnosed autoimmune gastritis (AIG) through endoscopic manifestations, histological and serological tests. After the identification of this disease subtype, the correlations among these diseases within the group strengthened the rationale for implementing targeted screening strategies in these various autoimmune disorders. Future research is expected to identify the targets and new directions for treating these immune-related diseases through these correlational studies.