musculoskeletal and connective tissue disorders
IgG4 Related Disease
Pathology of IgG4 Related Disease
IgG4-RD is characterized by a dense lymphoplasmacytic infiltrate composed of CD3+ T cells, activated B cells, and plasma cells with a disproportionate number expressing IgG4 (usually > 40% of all IgG expressing cells) ( Pathology reference ). Classically, inflammation progresses over time to fibrosis with a characteristic "storiform" or whorled pattern. Additional features include obliterative phlebitis and a mild eosinophilic infiltrate. Importantly, the eosinophilic component should not be more prominent than the lymphoplasmacytic infiltrate. The histopathology may differ slightly among tissues, for instance, typical storiform fibrosis is less commonly observed in lacrimal gland, parotid gland, and lung biopsies. Deshpande V, Zen Y, Chan JK, et al: Consensus statement on the pathology of IgG4-related disease.Mod Pathol25(9):1181-1192, 2012. doi:10.1038/modpathol.2012.72 