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Cavitating pulmonary lesions are areas of lung parenchymal necrosis that communicate with the bronchial tree, producing an air-filled cavity visible on imaging. They may occur due to infection, malignancy, autoimmune disease, or vascular causes.
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| Infectious (most common) | Bacterial: • Tuberculosis (post-primary TB – upper lobes, thick-walled cavities). • Staphylococcus aureus pneumonia (post-influenza, abscess). • Klebsiella pneumoniae (bulging fissure, cavitation). • Gram-negative organisms (Pseudomonas, Enterobacter). Fungal: • Aspergillosis (aspergilloma in pre-existing cavity). • Histoplasmosis, blastomycosis. Parasitic: • Echinococcus (hydatid cyst rupture → cavity). Septic emboli: Cavitary nodules (IV drug use, right-sided endocarditis). | | --- | --- | | Malignancy | • Primary lung cancer: Squamous cell carcinoma (most common cavitating carcinoma). • Metastases: From squamous cell tumors (head & neck, cervix, GI tract). | | Autoimmune / Inflammatory | • Granulomatosis with polyangiitis (GPA) – multiple cavitating nodules. • Rheumatoid nodules (may cavitate). • Sarcoidosis (rare cavitation). | | Vascular | Pulmonary infarction (secondary infection → cavity). | | Other | Trauma (pulmonary laceration → post-traumatic pseudocyst). |
| Modality | Imaging features |
|---|---|
| CXR | • Radiolucent area within a consolidation/mass. |
| • May show air-fluid level (lung abscess). | |
| CT | Wall thickness: |
| • Thin wall (<4 mm) → benign (resolving abscess, bulla). | |
| • Thick wall (>15 mm) → suspicious for malignancy. |
Etiological subtypes:
| Etiology | Imaging features |
|---|---|
| Infective cavities | Irregular, thick walls, often with air-fluid levels. |
| TB | Thick-walled upper lobe cavities ± satellite nodules. |
| Septic emboli | Mutiple peripheral cavitating nodules. |
| Aspergilloma | Fungus ball with air crescent sign in pre-existing cavity. |
| Squamous carcinoma | Solitary thick-walled cavitating mass, often central. |