Successful treatment of sclerosing mediastinitis with a high serum IgG4 level.

Sclerosing mediastinitis is not a common condition in the thoracic cavity and is difficult to cure. Several medications have been used; however, most of the cases do not achieve satisfactory results, and the most successful treatment is operative resection. We report the first case of IgG4-related sclerosing mediastinitis that showed IgG4-positive plasma cells infiltrated into the fibrous tissue and a high serum IgG4 level. The patient clearly showed remission of the symptoms after steroid therapy. Our findings suggest that the serum IgG4 level is a good selection indicator for steroid therapy in sclerosing mediastinitis.