Rev Pneumol Clin. 2009 Jun; 65(3): 159-63Maalej S, Zidi A, Ayadi A, Chorfa A, Bourguiba M, Kilani T, Ben Kheder A, Drira IMediastinal fibrosis or fibrosing mediastinitis is a rare condition characterized by chronic fibrosis occurring in mediastinal structures, in proliferating fibrous scar tissue. The disease may be secondary or idiopathic. The authors report the case of a 46-year-old woman, without a particular past history, who, in December 2006, presented dyspnoea on exertion and a superior vena cava syndrome. Her chest X-ray showed a right laterotracheal opacity. Fiberoptic bronchoscopy revealed concentric tracheobronchial narrowing, severe hyperemia and mucosal edema. The chest computed tomography documented the obstruction of the superior vena cava, the right main bronchus and the right upper lobe bronchus secondary to a mediastinal mass. Mediastinoscopy revealed a hard and dense mass, surrounding the different structures of the mediastinum. Pathologic examination corroborated mediastinal fibrosis. No cause was determined. Prednisone and anticoagulant were prescribed during 2 years with a regression of dyspnoea and the superior vena cava syndrome and an important regression of radiological lesions. In conclusion, prolonged corticosteroids may be efficient in the treatment of idiopathic mediastinal fibrosis.