The spectrum of mass-forming IgG4related sclerosing disease includes fibroinflammatory masses (some of which resemble pulmonary hyalinizing granuloma, see below); inflammatory pseudotumor, plasma cell granuloma type; and sclerosing mediastinitis
1,3,5) Retroperitoneal fibrosis, sclerosing cholangitis, Riedel thyroiditis, and sclerosing mediastinitis
are all associated with orbital pseudotumors, and they provide a basis for a unifying autoimmune or genetic cause.
8) Some cases of sclerosing mediastinitis, which may secondarily affect the lung, have also been reported as a manifestation of IgG4 systemic sclerosing disease.
Sclerosing mediastinitis consists of a fibroinflammatory mass within the mediastinum that often secondarily obstructs the trachea and bronchi, esophagus, and veins.
Inoue et al (9) reported a case of sclerosing mediastinitis accompanied by high serum levels of IgG4.
The observations suggest that idiopathic cases of sclerosing mediastinitis may sometimes be a manifestation of IgG4-related sclerosing disease.
Successful treatment of sclerosing mediastinitis with a high serum IgG4 level.
Sclerosing mediastinitis and hyalinizing granuloma share similar histologic features and are both thought to be immunologically derived.
Sclerosing mediastinitis is a rare condition thought to result from many etiologies, an abnormal immunologic response to histoplasmosis being the most prominent one in the United States (Table 2).
Radiologically, sclerosing mediastinitis is divided between 2 types: focal, the most common, and diffuse.
The gross findings for sclerosing mediastinitis are described as tan-yellow, gelatinous masses to gray-white, hard masses that compress or infiltrate mediastinal structures (Figure 6, a).
3] It has also been described as part of multifocal or systemic fibrosclerosis, a disease spectrum that also includes retroperitoneal fibrosis, sclerosing mediastinitis
, Riedel thyroiditis, and orbital pseudotumor.