Fibrosing mediastinitis (FM), also known as mediastinal fibrosis or sclerosing mediastinitis, is a rare disorder characterized by proliferation of fibrous tissue within the mediastinum.[sup] Although FM is a benign disease, it is often progressive and leads to compression and occlusion of mediastinal structures.
Sclerosing mediastinitis: Improved management with histoplasmosis titer and ketoconazole.
Microscopically, a sclerosing thymoma can mimic sclerosing mediastinitis
, solitary fibrous tumors, or lymphoma with prominent sclerosis in a limited biopsy specimen.
(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.
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
(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.
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.
Fewer than 300 cases have been reported in the literature since it was first described by Jura in 1924.[1,2] It has been reported under many different names; the names most frequently used in the literature, in addition to sclerosing mesenteritis, include mesenteric lipodystrophy, mesenteric panniculitis, and retractile mesenteritis. 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.