Background: Immunoglobulin G4 (IgG4)-related gastrointestinal diseases (IgG4-GID) are becoming increasingly recognized. However, few cases have been reported, and the disease concept is not yet well established. This study aimed to elucidate the clinical features of IgG4-GID.
Methods: This nationwide multicenter retrospective study collected 37 cases of IgG4-GID, which were classified and analyzed based on the pathological findings and the presence or absence of IgG4-related diseases in other organs. The pathological possibility of IgG4-GID was classified as definite, highly likely, probable, or unlikely based on the presence of typical pathological findings, number of IgG4-positive cells, and adequacy of histological evaluation.
Results: Thirteen patients were classified as unlikely to undergo pathological evaluation. Among the remaining 24 cases, 20 had other organ involvement (pathologically definite, n = 8; highly likely, n = 6; probably, n = 6). The four cases without the involvement of other organs were classified as definite. After defining definite and highly likely cases, 18 cases of IgG4-GID were identified. The most commonly affected organs were the stomach (n = 12) and the duodenum (n = 6), with one case involving both. Endoscopic findings most frequently showed ulcers (n = 7), followed by submucosal tumor (SMT)-like morphology (n = 6). Treatments included surgery (n = 8; SMT-like cases), steroids (n = 2), and proton pump inhibitors or potassium-competitive acid blockers (n = 3), with all cases showing improvement.
Conclusions: IgG4-GID exhibits characteristic pathological findings and various endoscopic features. Although many patients respond to treatment, some undergo surgery; thus, increased awareness may help avoid unnecessary surgeries.
Keywords: Clinical outcome; Endoscopy; IgG4-related gastrointestinal disease; Treatment.
© 2025. The Author(s), under exclusive licence to Japanese Society of Gastroenterology.