Immunoglobulin-g4(IgG4)-rich Pseudotumor of the Kidney – A case report and review of the literature

Abstract

IgG4-related disease is a newly identified fibroinflammatory condition characterized by tumefactive lesions, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells and storiform fibrosis. Elevated serum IgG4 levels are frequently observed. IgG4-related disease affects predominantly middle-aged and elderly patients, with male predominance and responds favorably to steroids. The patients present with symptoms referable to the involvement of one or more sites either simultaneously or serially, usually in the form of mass lesions affecting various organs including pancreas, biliary tree, salivary glands, periorbital tissues, kidneys, lungs, retroperitoneum and lymph nodes. The case of a 61-year old male referred for therapy of a 6.6 cm tumorous lesion of the right kidney is presented. Histological assessment of the resected mass showed IgG4-rich sclerosing pseudotumor. The available literature is summarized, and diagnostic and therapeutic options for this condition are discussed. Consideration of a non-malignant disease may be reasonable even in cases of CAT scan findings suggestive of renal cancer.