What is pulmonary blastoma?
Pulmonary blastoma is an ultra-rare type of lung cancer. Under the microscope it resembles the lung tissue of a developing fetus. Classic pulmonary blastoma is biphasic, meaning it contains two malignant components: gland-forming cells similar to adenocarcinoma, and a primitive connective tissue component similar to sarcoma.
It accounts for only a very small fraction of lung cancers. It is usually diagnosed in adults, most often in their forties, and the majority have a history of smoking.
Related but different tumours
Two other tumours have similar names. Well-differentiated fetal adenocarcinoma contains only the gland-forming component, is now classified as a type of adenocarcinoma, and generally has a better outlook. Pleuropulmonary blastoma is a separate childhood tumour, often linked to inherited DICER1 gene variants. It is treated by paediatric oncology teams, and children are managed jointly with paediatric pulmonology.
Symptoms
Pulmonary blastoma often grows as a single, large mass in the outer part of the lung. A proportion of patients have no symptoms and the tumour is found on a chest X-ray. When symptoms occur they may include:
- Persistent cough
- Coughing up blood
- Chest pain
- Breathlessness
- Fever, tiredness and weight loss
These symptoms are shared with more common conditions such as pneumonia, tuberculosis and other lung cancers, so a cough lasting more than three weeks or any blood in the sputum should be investigated.
Causes and risk factors
Cigarette smoking is the main recognised risk factor for classic pulmonary blastoma. The tumours frequently carry acquired mutations in the CTNNB1 gene, which controls the beta-catenin signalling pathway involved in lung development. These mutations arise within the tumour and are not inherited. In contrast, childhood pleuropulmonary blastoma is often associated with an inherited DICER1 variant, which is why genetic counselling is offered to those families.
How pulmonary blastoma is diagnosed and staged
Diagnosis requires tissue, and staging determines whether surgery is possible.
| Test | What it shows |
|---|---|
| Contrast CT chest and upper abdomen | The size and position of the mass and any spread within the chest |
| PET-CT | Spread to lymph nodes and distant organs |
| CT-guided or bronchoscopic biopsy | Tissue for diagnosis, although the biphasic pattern may only be confirmed after complete surgical removal |
| EBUS-TBNA | Sampling of mediastinal lymph nodes for accurate staging |
| Brain MRI | Spread to the brain |
| Lung function tests | Whether the patient can safely undergo lung surgery |
A small biopsy may show only one component and be reported as adenocarcinoma or sarcoma, so review by a pathologist experienced in thoracic tumours is important. Bronchoscopy also helps exclude infection, including tuberculosis.
Treatment
Treatment is planned by a multidisciplinary tumour board including pulmonology, thoracic surgery, medical oncology, radiation oncology, radiology and pathology.
Surgery
Complete surgical removal, usually lobectomy with lymph node dissection, is the main treatment and offers the best chance of long-term control when the tumour is localised.
Additional treatment
Because recurrence is common, chemotherapy and sometimes radiotherapy may be offered after surgery, particularly for large tumours or lymph node involvement. The evidence comes from case series, so decisions are individualised.
Advanced disease
For tumours that cannot be removed or have spread, chemotherapy regimens used for lung cancer or sarcoma, radiotherapy, and clinical trials are considered. Tumour molecular profiling may identify additional treatment options. Supportive measures, such as drainage of pleural effusion or interventional bronchoscopy for airway obstruction, help control symptoms.
Stopping smoking
Stopping smoking improves surgical recovery and overall health and is supported at every stage.
Outlook and follow-up
Classic biphasic pulmonary blastoma is an aggressive tumour and recurrence after surgery is common, especially with larger tumours or spread at diagnosis. Patients with small, completely removed tumours do better. Well-differentiated fetal adenocarcinoma has a considerably more favourable outlook. Regular follow-up with clinical review and CT scans is needed for several years after treatment.
When to seek urgent care
Seek urgent medical help for coughing up more than a small amount of blood, sudden or severe breathlessness, chest pain, fever during chemotherapy, sudden severe headache, weakness or confusion, or swelling of the face and neck.
Frequently asked questions
Is pulmonary blastoma the same as pleuropulmonary blastoma?
No. Pulmonary blastoma occurs mainly in adults and is linked to smoking. Pleuropulmonary blastoma is a separate tumour of young children, often associated with an inherited DICER1 gene variant, and is treated by paediatric oncology teams.
Can pulmonary blastoma be cured?
When the tumour is small and completely removed by surgery, long-term control is possible. Because recurrence is common, additional treatment and regular follow-up are often recommended.
Why was my first biopsy report different?
Pulmonary blastoma contains two components, and a small needle biopsy may sample only one of them. The full diagnosis is sometimes made only after the whole tumour has been removed and examined.
Is pulmonary blastoma caused by smoking?
Most adults with classic pulmonary blastoma have a history of smoking, and smoking is the main recognised risk factor. Stopping smoking is strongly recommended.
Do my family members need testing?
For adult pulmonary blastoma, the gene changes are usually acquired and family testing is not needed. For childhood pleuropulmonary blastoma, genetic testing for DICER1 is offered to the family.
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.