[IgG4-related systemic sclerosing disease: a review].

IgG4-related systemic sclerosing disease (SSD) is a multisystemic condition characterized by an increased number of IgG4-producing plasma cells which occurs mainly in older men. SSD involves particularly pancreas, hepatobiliary system, salivary glands and retroperitoneum. Microscopically, the findings include lymphoplasmacytic inflammation, fibrosis and vascular changes in the form of obliterative phlebitis. Using immunohistochemistry, an increased number of IgG4-positive plasma cells might be detected in affected tissues. Since SSD frequently mimicks a malignancy both clinically and radiologically, this inflammatory sclerosing condition should be considered in the differential diagnosis of neoplastic and/or pseudoneoplastic lesions.