IgG4-related disease (IgG4-RD) is a multi-organ fibroinflammatory condition that has now been described to affect essentially every organ system. Rheumatologists are frequently called upon to evaluate this disease because of its propensity to involve the salivary glands, orbits, lymph nodes, lungs, kidneys, aorta, and retroperitoneum. IgG4-RD often causes mass lesions and is therefore misdiagnosed frequently as a cancer, but it can also closely mimic common rheumatologic disorders such as Sjögren's syndrome, systemic lupus erythematosus, and granulomatosis with polyangiitis (formerly Wegener's), and large-vessel vasculitis.

Both the diagnosis and treatment of IgG4-RD are challenging. This lecture will emphasize the multiple clinical features of IgG4-RD and its characteristic pathology findings, all in the context of treatment dilemmas. IgG4-RD is an immune-mediated condition that has lent itself well to therapeutic manipulations such as B cell depletion. Treatment efforts to date have yielded much knowledge about the nature of this disease and the larger immune system that drives IgG4-RD.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.6350