If your foreign worker has pulmonary granuloma, he is considered unfit for employment in Malaysia. Why?
Granulomas are known to harbour tubercle bacilli. These bacilli are dormant and may become re-activated anytime the patient’s immunity drops. In fact, granulomas contain macrophages, T & B lymphocytes and fibroblasts. By forming an aggregate, they prevent dissemination of mycobacterium. Within the granulomas, T lymphocytes (CD4+) secrete cytokines such as interferon gamma, which activates macrophages to destroy the bacteria with which they are infected. Without doubt, granuloma is an important form of body defense against tuberculous infection.
How do granulomas appear on chest radiograph?
Granulomas are seen as rounded discrete nodules between 3-8mm in diameters. Typically, they are within the upper lobes but may be seen at any part of the lung fields. They may also calcify and are then called calcified granulomas. They may also have satellite lesions (ie, small discrete nodules in the vicinity of the granuloma).
How do you differentiate them from end-on vessels?
I would say this is the most common dilemma in chest x-ray reporting. Granulomas and end-on vessels may look alike and differentiating them can sometimes be difficult. This is especially so if the ‘nodule’ is in the middle 1/3 of the lung field.
Can you see the nodule? I forgive you if you cannot see the it as granulomas are often between 3-8mm in size.MY RULES OF THUMB ARE:
- Granuloma is more likely if the ‘nodule’ is in the upper zones or the outer 1/3 of the lung fields.
- Granuloma is less likely if the ‘nodule’ is in the medial 1/3 of the lung fields.
- Granuloma is less likely if there is a vascular structure leading to or adjacent to the ‘nodule’.
- Granuloma is less likely if there is an end-on bronchus next to it (appears as a rounded hollow shadow).
- Granuloma is more likely if the ‘nodule’ is calcified.
What to do if you are still unsure?
- Send the film for 2nd opinion reporting.
- Request for a CT scan of the chest.