Tracheobronchopathia osteoplastica (TO) is a rare condition of the large airways. It is characterized by the presence of multiple growths (nodules) made of bone and cartilage tissue, in the submucosa of the tracheobronchial wall. The nodules protrude into the spaces inside the trachea and bronchi, which can lead to airway obstruction. Affected people may have persisting or recurrent respiratory symptoms, and/or recurrent infections. The cause of TO is not currently known. There is no specific treatment to prevent the formation of nodules. Laser therapy or removal of the nodules may be needed in some cases.

The underlying cause of tracheobronchopathia osteoplastica (TO) remains unknown. Several theories have been proposed, including chronic airway inflammation, exostosis (formation of new bone), and metaplasia (abnormal cell changes) in the affected tissue. Numerous cases have been reported in association with different conditions including allergic rhinitis. However, no theories have been validated. There is no known genetic susceptibility to the development of TO.

There is no known genetic susceptibility to the development of TO, and it typically occurs in people with no known history of the condition in their family. Familial occurrence has been reported only once, in a woman and her daughter.

Symptoms of tracheobronchopathia osteoplastica (TO) may be absent or non-specific. Affected people may have various respiratory symptoms such as cough, wheezing, coughing up blood (hemoptysis), and/or recurrent upper airway infections. Stridor and low-pitched wheezing may occur if there is severe airway obstruction. In some cases, obstruction of the lobar bronchi can cause recurrent atelectasis (collapse of the lung) or pneumonia. Nodules seem to remain stable over years, or progress at a very slow rate. It is thought that over 90% of cases are diagnosed incidentally on autopsy. Rapid progression has been reported rarely.

Fiberoptic bronchoscopy is thought to be the best procedure to diagnose tracheobronchopathia osteoplastica (TO). This procedure is done when it is important to see the airways or to get samples of mucus or tissue from the lungs. It involves placing a thin, tube-like instrument through the nose or mouth and down into the lungs. During this procedure a bronchial biopsy is usually performed, but samples are sometimes hard to obtain. TO is usually an incidental finding during fiberoptic bronchoscopy, and is rarely suspected before the procedure is done.

There is no specific treatment for tracheobronchopathia osteoplastica (TO). Recurrent infections and collapse of the lung are treated conventionally. Inhaled corticosteroids may have some impact on people in early stages of the condition, but whether they may be helpful for people with more advanced disease needs further study. Occasionally, tracheostomy may be needed. Surgical treatment options may be considered when all conservative therapies have been unsuccessful. The long-term outlook (prognosis) for affected people is generally good, but usually depends on the extension and location of the lesions. It has been reported that over 55% of affected people do not have any disease progression following the diagnosis.