Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody IHC IgG4 is used in distinguishing IgG4 related sclerosing disease from inflammatory myofibroblastic tumour. IgG4 related sclerosing disease is a syndrome affecting various sites with elevated serum IgG and site related lymphoplasmacytic infiltrates, increased IgG4 related plasma cells and sclerosis.