Serosal involvement in IgG4-related disease: report of two cases and review of the literature.

IgG4-related disease (IgG4-RD) is a recently described entity characterized by lymphoplasmacytic infiltrates, usually mimicking tumors, affecting almost every organ or system. Nevertheless, serosal involvement has been rarely reported. In this article, we report two cases of IgG4-RD with serosal involvement and review the literature. Because of the varied clinical pictures found in our review, we suggest a new terminology for the description of IgG4-RD with serosal involvement.