Aetiology of solitary pulmonary nodules
| Type | Aetiology |
| Infectious | Tuberculosis Atypical mycobacteria Fungal (histoplasmosis, coccidioidomycosis, cryptococcosis) Parasitic Nocardia Measles Pneumocystis jirovecii Round pneumonia Lung abscess Septic embolism Infected bulla |
| Neoplastic benign | Pulmonary hamartoma Benign mesenchymal tumours (lipoma, fibroma, chondroma, haemangioma, leiomyoma) Neural tumours (schwannoma, neurofibroma, paraganglioma) Sclerosing pneumocytoma Plasma cell granuloma Endometriosis |
| Neoplastic malignant | Lung cancer Neuroendocrine tumours (well differentiated, moderately differentiated, and poorly differentiated) Metastasis Malignant teratoma |
| Vascular | Haematoma Arteriovenous malformation Pulmonary artery aneurysm Pulmonary venous varix Lung infarct |
| Congenital | Bronchogenic cyst Lung sequestration |
| Inflammatory | Rheumatoid nodules Sarcoidosis Granulomatosis with polyangiitis Microscopic polyangiitis |
| Miscellaneous | Round atelectasis Lipoid pneumonia Amyloidosis Mucoid impaction Focal scar |
| Lymphatic | Intrapulmonary lymph node Lymphoma |
Reproduced and modified from [8] with permission.