OBJECTIVE To identify the aetiologies of pulmonary cavities and the clinical predictors of cavities of mycobacterial origin.

SETTING A tertiary referral hospital in South Korea, where the prevalence of tuberculosis (TB) is intermediate.

DESIGN A retrospective review of clinical records and radiographic examinations of patients presenting pulmonary cavities on simple chest radiograph between January and December 2005.

RESULTS Of 131 patients enrolled with pulmonary cavities, 66 (50.4%) had cavities of mycobacterial origin. Age <50 years (P = 0.04) and largest cavity located in the upper lobes (P = 0.04) increased the likelihood that the cavities were of mycobacterial origin. Conversely, history of malignancy (P = 0.02), lesions confined to one lobe (P = 0.02) and multiple enlarged mediastinal lymph nodes (P = 0.03) suggested a non-mycobacterial cause.

CONCLUSION Mycobacterial infection accounted for half of the cavitary lesions identified in this study. In older patients with a history of malignancy, non-nodular infiltration, lesions confined to one lobe and with multiple lymphadenopathy, diseases not caused by mycobacteria should be considered.