A recently described mass-forming lesion that occurs in the pancreas, submandibular glands, lacrimal glands, lymph nodes, and hepatobiliary tract. It is characterized by the presence of marked tissue sclerosis and infiltration by numerous plasma cells. The plasma cells show immunohistochemical staining for IgG4 and the serum IgG4 levels are often increased. The disease is immunoglobulin G4-related sclerosing disease (MONDO_0017287). Also known as: IgG4-RD, IgG4-related disease, IgG4-related sclerosing disease, IgG4-related systemic disease.