Idiopathic hilar fibrosis
Patients with hilar fibrosis typically present at younger ages than with typical mediastinal fibrosis. The etiology of hilar fibrosis is unknown, but most cases of fibrosing mediastinitis are believed to be secondary to histoplasmosis. Some cases have been associated with tuberculosis.
Clinical presentation and prognosis of idiopathic hilar fibrosis is variable and depends on the structures involved. Patients may have pleural thickening, tracheobronchial narrowing, and obstruction, compression, or stenosis of the pulmonary vessels. This can result in dyspnea, hemoptysis, and pulmonary hypertension. Asymptomatic patients often present with incidental imaging findings of an unknown mediastinal mass.
Asymptomatic patients can safely be monitored and often have a good prognosis with little progression of their fibrosis. Symptomatic patients often have more advanced disease progression and are difficult to manage. Bilateral involvement is associated with higher mortality.
Treatment depends on the affected mediastinal structures, the severity of the scarring, and, in some cases, the cause of the condition.
J98.59 – Other diseases of mediastinum, not elsewhere classified
361196000 – Idiopathic Hilar Fibrosis
Differential Diagnosis & Pitfalls
- Mediastinal fibrosis, retroperitoneal fibrosis, or pulmonary fibrosis
- Interstitial pulmonary pathology: sarcoidosis, histiocytosis, granulomatosis with polyangiitis (Wegener granulomatosis), eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), cryptogenic organizing pneumonitis, radiation pneumonitis
- Pneumoconiosis: coal worker pneumoconiosis, asbestosis, silicosis, berylliosis
- Cardiovascular: aneurysms, pulmonary artery stenosis, pulmonary embolism
- Rheumatologic: rheumatoid arthritis, Behçet syndrome
- Cancer: lymphoma, teratoma, thymoma, thyroid cancer, metastatic cancer, lung cancer, mesothelioma
- Infectious: histoplasmosis, aspergillosis, blastomycosis, coccidioidomycosis, tuberculosis, mucormycosis