Mediastinal granuloma and mediastinal fibrosis.

Mediastinal granuloma/mediastinal fibrosis is a chronic inflammatory disease of the mediastinum. Mediastinal granuloma is the abnormal enlargment of mediastinal lymph nodes by granulomatous inflammation, is usually asyptomatic or minimally symptomatic, and is often detected on chest radiographs taken for other reasons. In contrast, mediastinal fibrosis is extensive fibrous tissue throughout the middle mediastinum causing compression, encasement, or invasion of the large bronchi, superior vena cava, pulmonary veins, or esophagus, often with serious clinical consequences. Some patients may exhibit a clinical entity characterized by enlarged fibrotic and/or calicified lymph nodes with a variable amount of fibrosis that may be asymptomatic, or may cause symptoms by compression or invasion of structures in the mediastinum. Clinical manifestations may be due to superior vena cava (SVC) obstruction, esophageal compression, large airway involvement, pulmonary artery or pulmonary vein narrowing, or laryngeal or phrenic nerve impingement. Definitive diagnosis is traditionally made on the basis of a surgical exploration and biopsy, either a mediastinoscopy or thoracotomy; however, characteristic findings on computed tomography (CT) of the chest may be sufficient for a diagnosis in a certain number of cases. The best therapy is unknown. Antifungal therapy and corticosteroids have been reported effective in some cases. Surgical resection of localized mediastinal granuloma or fibrosis causing symptoms is often effective. However, surgical resection of extensive mediastinal fibrosis usually is not feasible.