What is primary pulmonary lymphoma?
Lymphoma is a cancer of lymphocytes, the white blood cells of the immune system. It usually begins in lymph nodes, and the lungs are commonly affected when lymphoma spreads. Primary pulmonary lymphoma is different: the lymphoma starts in the lung itself, with no evidence of disease elsewhere at the time of diagnosis, or only in nearby chest lymph nodes.
It is rare, accounting for a very small fraction of all lung tumours and lymphomas. The commonest type, by a wide margin, is extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), which grows slowly. Less common types include diffuse large B-cell lymphoma, which is faster-growing, and lymphomatoid granulomatosis, a rare Epstein-Barr virus driven condition.
The pulmonologist's role is mainly in recognising the condition and obtaining adequate tissue. Treatment is planned with haematology-oncology.
Symptoms
Many patients with MALT lymphoma have no symptoms, and the abnormality is found on a scan done for another reason. When symptoms occur, they include:
- Persistent cough
- Breathlessness
- Chest discomfort
- Coughing up blood: uncommon
- B symptoms: fever, drenching night sweats and unintentional weight loss, more typical of high-grade lymphoma
A key clue is a patch of lung change that looks like pneumonia but does not clear despite antibiotics over several weeks.
Causes and risk factors
MALT lymphoma of the lung is thought to develop from lymphoid tissue that forms in the airways in response to long-term immune stimulation. Recognised associations include:
- Autoimmune diseases, particularly Sjogren's syndrome, as well as rheumatoid arthritis and lupus
- Lymphocytic interstitial pneumonia and other lymphoproliferative lung disease
- Immune deficiency, including HIV infection and medication after organ transplantation
- Chronic inflammation from long-standing infection or smoking
Most patients are in their fifties or sixties. Lymphoma is not contagious and is not usually inherited.
How primary pulmonary lymphoma is diagnosed
A firm diagnosis needs a tissue sample large enough for the pathologist to study the cells, their markers and their genetic features. Small needle samples may not be sufficient.
| Test | What it shows |
|---|---|
| CT chest | A persistent consolidation, mass or multiple nodules, often with air bronchograms |
| Bronchoscopy with lavage and biopsy | Lymphocyte excess, exclusion of infection and sometimes diagnostic tissue |
| CT-guided core biopsy or surgical biopsy | Larger samples for full lymphoma classification |
| Immunohistochemistry and gene studies | Lymphoma type and confirmation that cells are a single clone |
| PET-CT and bone marrow tests | Staging to confirm the disease is confined to the lung |
Persistent lung shadows in India are frequently treated empirically as tuberculosis. When TB tests are negative and the shadow does not respond, a biopsy should be considered rather than continuing treatment indefinitely. Bronchoscopy and EBUS-TBNA can sample airway lesions and chest lymph nodes.
Treatment
Treatment depends on the lymphoma type, stage, symptoms and overall health, and is decided with the haematology-oncology team.
MALT lymphoma
Because it grows slowly, some patients without symptoms are safely observed with regular scans. Where treatment is needed, options include surgical removal of a single localised lesion, low-dose radiotherapy, rituximab alone, or rituximab combined with chemotherapy for more extensive disease.
Diffuse large B-cell lymphoma
This faster-growing type is treated with combination chemotherapy with rituximab (R-CHOP or similar regimens), sometimes followed by radiotherapy.
Supportive care
Vaccinations, infection prevention, and management of any associated autoimmune disease with rheumatology are part of overall care.
Outlook and follow-up
The outlook for pulmonary MALT lymphoma is generally very good, with most patients living for many years, although the disease may recur. High-grade lymphoma is more serious but is often responsive to treatment. Long-term follow-up includes clinical review and imaging to detect recurrence or transformation to a more aggressive type.
When to seek urgent care
Seek urgent medical attention for fever during chemotherapy, breathlessness at rest, coughing up blood, chest pain, or swelling of the face and neck. Fever in a patient receiving chemotherapy can signal a serious infection and should be treated as an emergency.
Frequently asked questions
Is primary pulmonary lymphoma the same as lung cancer?
No. Lung cancer arises from the cells lining the airways and lungs, while lymphoma arises from immune cells. They are treated very differently, and lymphoma often responds well to treatment.
Why did my doctor not start treatment straight away?
MALT lymphoma often grows very slowly. If it is not causing symptoms, careful observation with regular scans may be safer than treatment, which can be started if the disease progresses.
Why was my lung shadow treated as pneumonia or TB first?
Lymphoma in the lung can look very similar to infection on a scan. A shadow that does not resolve with appropriate treatment, especially with negative TB tests, is a reason to obtain a biopsy.
Why do I need a larger biopsy?
Lymphoma classification depends on the structure of the tissue and specialised stains and gene tests. Small samples are sometimes inconclusive, so a core or surgical biopsy may be required.
Can it come back after treatment?
MALT lymphoma can recur, sometimes years later, but recurrences are usually treatable. This is why follow-up continues long after treatment ends.
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.