IgG4-positive plasma cells in inflammatory pseudotumor (plasma cell granuloma) of the lung

The association between IgG4 dysregulation and inflammatory pseudotumor (IPT) was first reported in sclerosing pancreatitis. Recently, we described IPTs of the liver and breast, into both of which many IgG4-positive plasma cells had infiltrated. In this study, we examined the clinical and histological features of 9 cases of IPT (histologically corresponding to plasma cell granuloma) of the lung with an emphasis on IgG4-positive plasma cell...