11% of primary lung cancers (cancers that start in the lung) have cavities that can be seen on chest X-ray; 22% of primary lung cancers will have cavities on CT, which is more sensitive. Squamous-cell carcinoma of the lung is more likely to develop cavitations than lung adenocarcinoma or large-cell lung carcinoma. Other primary cancers of the lung, such as lymphoma and Kaposi’s sarcoma, can also cavitate, especially in people with AIDS. Lung cancers that develop cavities are associated with a poor prognosis (worse outcomes). Cancers that metastasize (spread) to the lung can also develop cavitations, but this is only seen about 4% of the time on X-ray. Metastatic cancers of squamous cell origin are also more likely to cavitate than cancers of other origins. Both chemotherapy (drugs to treat cancer) and radiofrequency ablation (destroying cancer with radio waves) can cause lung cancers to develop cavities, which is a sign of a good response to treatment. It is possible to have both an infection and lung cancer in the same cavity; the most common combination is primary lung cancer and tuberculosis. Autoimmune
Autoimmune causes of lung cavities include granulomatosis with polyangiitis, rheumatoid arthritis, and rarely necrotizing sarcoidosis (less than 1% of people with sarcoidosis develop lung cavities). Ankylosing spondylitis, eosinophilic granulomatosis with polyangiitis, and systemic lupus erythematous rarely cause lung cavities.
Although NTM lung infections can cause lung cavities, the most common finding on imaging is bronchiectasis, which may occur with or without cavities. Mycobacterium avium complex (MAC) is the most common cause of NTM lung disease in most countries, including the United States. Classically, MAC infection results in either upper lobe cavities in male smokers with COPD or bronchiectasis in thin, older women; however, it is possible to have both cavities and bronchiectasis in the same patient. Similar to tuberculosis, the presence of cavities in MAC infection is associated with worse outcomes. Mycobacterium kansasii, Mycobacterium xenopi, and the rapidly-growing Mycobacterium abscessus have also been associated with lung cavities. Fungal
Fungal infections that can cause cavitations include histoplasmosis, coccidiomycosis, cryptococcosis, and aspergillosis. Aspergillosis, most commonly caused by Aspergillus fumigatus, can present in four different ways (listed in order of increasing severity): aspergilloma, allergic bronchopulmonary aspergillosis (ABPA), chronic necrotizing aspergillosis, and invasive aspergillosis. All of these are associated with lung cavities except for ABPA, which is a hypersensitivity response associated with bronchiectasis on imaging. An aspergilloma is an infection of a pre-existing lung cavity by Aspergillus species without tissue invasion and results in the formation of a fungal ball. Historically, tuberculosis was the most common cause of the lung cavity (and still is in areas where tuberculosis is endemic); however, the cavity can also be caused by sarcoidosis, bullae, bronchiectasis, or cystic lung disease. Chronic necrotizing aspergillosis and invasive aspergillosis are usually seen in immunocompromised people.