IgG4-related disease (IgG4-RD) is a systemic fibrotic-inflammatory disease characterized by elevated serum concentration of IgG4 and infiltration of tissues by plasma cells. IgG4-RD may occur as an isolated disease or co-exist with other inflammatory conditions, such as Mikulicz’s disease, autoimmune pancreatitis, sinusitis, thyroiditis, interstitial pneumonitis, nephritis, lymphadenopathy, inflammatory pseudotumor. IgG4-RD is a separate, clinically distinct disease entity, but due to its heterogeneous manifestation raises the interest of physicians with various specialties. The gold standard in the diagnosis is a histopathological examination.