Fibrosing mediastinitis

  • sclerosing mediastinitis or mediastinal fibrosis
  • fibrous tissue and collagen in mediastinum
  • sequel to infection from histoplasmosis or tuberculosis
  • sarcoidosis, autoimmune diseases, retroperitoneal fibrosis, radiation, drugs (methysergide maleate)
  • SVC obstruction, obstruction to central pulmonary artery or veins
  • two types: focal or diffuse. Focal in tuberculous/ histoplasmosis. Diffuse in idiopathic form, associated with retroperitoneal fibrosis
  • focal: calcified. diffuse: non calcified infiltrative
imaging
Chest xray
  • non specific
  • underestimates extent of disease
  • TB or fungal infection may show calcified lymph nodes
CT
  • infiltrative, extensively calcified hilar or mediastinal process
  • focal in tuberculous or histoplasmosis
  • diffuse in idiopathic form
MRI
  • intermediate on T1
  • variable signal on T2
  • low signal in T2 seen in fibrous components, distinguishes from other conditions like malignancy
  • heterogeneous enhancement post Gado