Malignancies and IgG4‐related disease

Abstract Immunoglobulin G4‐related disease (IgG4‐RD) is a systemic fibro‐inflammatory disease characterized by tumefactive lesions. Beyond the role of the disease as a cancer mimic, studies over the past decade have demonstrated that IgG4‐RD is associated with increased cancer risk. A search of articles, case reports, and reviews concerning malignancies in patients with IgG4‐RD was conducted on PubMed, Web of Science, and Google Scholar. The site of cancer development is not always affected by IgG4‐RD. The prevalence of solid cancers varies among populations. Moreover, B‐cell neoplasms constitute a proportion of the malignancies linked to this disease. The precise mechanism of oncogenesis in IgG4‐RD is ambiguous. Several mechanisms may be relevant to the increased cancer risk in patients with IgG4‐RD, including chronic inflammation, IgG4‐positive plasma cell infiltration, and the involvement of follicular helper T cells, macrophages, and plasmacytoid dendritic cells in tumor immunity. The risk factors include male sex, older age, smoking status, occupational exposure, disease recurrence, and involvement of specific organs. Malignancies in patients with IgG4‐RD are associated with a poor prognosis, underscoring the importance of cancer risk management and regular screening during follow‐up. The precise mechanisms linking IgG4‐RD to malignancy remain unclear and warrant further research. Regular cancer screening should be prioritized during follow‐up to facilitate early detection of malignancies.