What is tracheobronchopathia osteochondroplastica?
Tracheobronchopathia osteochondroplastica (TO, sometimes called TPO) is a rare, benign condition in which many small nodules of cartilage and bone form in the inner lining of the trachea (windpipe) and the main bronchi. The nodules grow from the cartilage rings, so they characteristically spare the soft back wall of the trachea, which has no cartilage.
At bronchoscopy the airway looks studded with hard, whitish nodules, often described as a rock garden or cobblestone appearance. The condition usually progresses very slowly over many years, and in most people it causes few problems.
TO is most often found in adults over 50 and is frequently discovered by chance during a CT scan, bronchoscopy or a difficult intubation for surgery.
Symptoms
Many people have no symptoms at all. When symptoms occur, they are usually non-specific and may be present for years before a diagnosis is made:
- Chronic cough, sometimes with sputum
- Recurrent chest infections or pneumonia, as nodules interfere with mucus clearance
- Coughing up small amounts of blood
- Breathlessness on exertion or noisy breathing
- Wheeze that may be mistaken for asthma
- Hoarseness if the larynx is involved
In a small number of people the nodules narrow the airway enough to cause significant breathlessness, and collapse of the lung segment beyond a narrowed bronchus can occur.
Causes and associations
The cause of TO is not known. Suggested contributors include chronic airway inflammation and infection, abnormal cartilage and bone growth signalling, and chemical or mechanical irritation. Some reports have described an association with atrophic rhinitis and with certain bacterial infections, but no single cause has been proven. TO is not cancerous, not contagious and not known to be inherited.
How TO is diagnosed
The diagnosis is usually made from the combination of CT and bronchoscopic appearances, supported by biopsy.
| Test | What it shows |
|---|---|
| CT chest with airway views | Multiple small, often calcified nodules along the front and side walls of the trachea and main bronchi, sparing the back wall |
| Flexible bronchoscopy | The typical hard, whitish nodules, and the degree of airway narrowing |
| Endobronchial biopsy | Cartilage and bone in the airway lining. Biopsies may be difficult because the nodules are hard |
| Lung function tests with flow-volume loop | Whether the nodules are causing significant central airway obstruction |
| Sputum culture | Infection that needs treatment |
Conditions to distinguish
Other conditions can cause nodules or thickening of the airway wall, including tracheobronchial amyloidosis, which typically involves the back wall as well, relapsing polychondritis, granulomatosis with polyangiitis, recurrent papillomatosis, and endobronchial or healed tuberculosis. In India, airway narrowing is often attributed to tuberculosis, so the distinctive pattern of TO is worth recognising to avoid unnecessary anti-tuberculosis treatment.
Treatment
There is no drug that removes the nodules or stops their formation, and most people need no specific treatment. Management is directed at symptoms and complications.
For most patients
- Prompt antibiotic treatment of chest infections, guided by sputum results
- Airway clearance techniques and physiotherapy where mucus is a problem
- Inhaled treatments for cough or wheeze in selected patients, although evidence is limited
- Influenza and pneumococcal vaccination, and avoidance of smoking
When the airway is significantly narrowed
Where nodules cause severe obstruction, interventional bronchoscopy can restore the airway. Options include mechanical removal of nodules with rigid bronchoscopy, laser or other thermal treatments, balloon dilatation and, rarely, airway stents. Surgery on the trachea is very rarely required and is planned with thoracic surgery.
Anaesthesia and intubation
People with TO should tell their anaesthetist before any operation, as the nodules can make passing a breathing tube difficult.
Outlook and follow-up
The outlook is generally good. TO tends to progress very slowly, and most people live a normal lifespan with few symptoms. Follow-up focuses on infections and on any change in breathlessness, with repeat lung function tests, CT or bronchoscopy when symptoms change.
When to seek urgent care
Seek urgent medical help for coughing up more than a small amount of blood, breathlessness at rest, noisy high-pitched breathing (stridor), or a chest infection with high fever and worsening breathing.
Frequently asked questions
Is tracheobronchopathia osteochondroplastica a cancer?
No. TO is a benign condition. The nodules are made of cartilage and bone and do not spread to other parts of the body.
Can the nodules be removed?
Nodules that cause significant airway narrowing can be removed bronchoscopically, for example with rigid bronchoscopy or laser. Most people do not need this, because the nodules usually cause little obstruction.
Will TO get worse over time?
TO usually progresses very slowly over many years, and in many people it remains stable. Regular review helps identify the few who develop significant narrowing.
Is TO the same as tuberculosis of the airway?
No. Endobronchial tuberculosis is an active infection that needs anti-tuberculosis treatment, whereas TO is a non-infectious condition. CT, bronchoscopy, biopsy and cultures help tell them apart.
Does TO affect surgery or anaesthesia?
It can. The nodules may make it harder to pass a breathing tube, so it is important to inform the anaesthetist about the diagnosis before any planned procedure.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.