Immunoglobulin G4 (IgG4)-related disease of the stomach - a challenging differential diagnosis in suspected gastric cancer.

ABSTRACT

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) can involve different organs and is diagnosed by a combination of clinicopathological features, including storiform fibrosclerosis infiltrated by numerous IgG4-positive plasma cells that frequently forms tumor-like lesions with or without associated obliterative phlebitis. Involvement of the stomach is rare and can occur as part of a multiorgan involvement of IgG4-RD or as isolated gastric involvement. CASE REPORT We report 2 female patients with therapy-refractory gastric ulcers associated with gastric wall thickening and lymphadenopathy that were highly suggestive of gastric cancer or lymphoma. Biopsies failed to confirm a diagnosis, and IgG4-RD was diagnosed only after surgical resection in both patients. The previous literature on gastric IgG4-RD is summarized and shows different characteristics in patients with multiorgan IgG4-RD and isolated gastric IgG4-RD. As reported for autoimmune pancreatitis type 1, patients with multiorgan IgG4-RD are mainly elderly men with frequently elevated serum IgG4 concentrations. In contrast, isolated gastric IgG4-RD predominantly affects female patients with normal serum IgG4 levels. Surgical resection is commonly performed due to the clinical suspicion of malignancy and the absence of findings indicative of IgG4-RD on biopsy. Today, diagnosis is confirmed histopathologically only after resection. CONCLUSION: IgG4-RD should be taken into account when gastric malignancy is suspected endoscopically or radiologically and biopsies fail to confirm the presence of a malignancy (especially subepithelial tumors or refractory gastric ulcers). Serum IgG4 concentrations are insufficient to confirm localized gastric IgG4-RD. Diagnostic workups need to be improved to avoid unnecessary surgical resections with the attendant potential morbidity and mortality.