[Tuberculosis of the lung bases]

Tuberculosis of the lung bases is a rare condition that can mimic pneumonia, bronchial carcinoma, lung abscess or bronchiectasis. Diagnostic delays, that can lead to serious complications not amenable to surgical resection, are often the result of repeatedly negative bacteriological examinations. We report a series of 10 cases of tuberculosis of the lung bases collected between 1993 and 1998 that were examined by computerised tomography. The chest x-ray most commonly showed a heterogeneous opacity. On the CT scan this corresponded with an area of alveolar consolidation which, when it was associated with centrilobular micronodules and cavitated nodules and masses, suggested the diagnosis of basal tuberculosis. Indeed the absence of apical lesions and the frequency of involvement of mediastinal and bronchial lymph nodes support the hypothesis of bronchial dissemination of the bacilli from tuberculous nodes. This explanation is supported by the high incidence of endobronchial lesions found at bronchoscopy in this form of tuberculosis.