Coexisting bronchogenic carcinoma and pulmonary tuberculosis in the same lobe: Radiologic findings and clinical significance

Objective: Bronchogenic carcinoma can mimic or be masked by pulmonary tuber culosis (TB), and the aim of this study was to describe the radiologic find ings and clinical significance of bronchogenic carcinoma and pulmonary TB w hich coexist in the same lobe. Materials and Methods: The findings of 51 patients (48 males and three fema les, aged 48-79 years) in whom pulmonary TB and bronchogenic carcinoma coex isted in the same lobe were analyzed. The morphologic characteristics of a tumor, such as its diameter and margin, the presence of calcification or ca vitation, and mediastinal lymphadenopathy, as seen at CT, were retrospectiv ely assessed, and the clinical stage of the lung cancer was also determined . Using the serial chest radiographs available for 21 patients, the possibl e causes of delay in the diagnosis of lung cancer were analyzed. Results: Lung cancers with coexisting pulmonary TB were located predominant ly in the upper lobes (82.4%). The mean diameter of the mass was 5.3 cm, an d most tumors (n=42, 82.4%) had a lobulated border. Calcification within th e tumor was seen in 20 patients (39.2%), and cavitation in five (9.8%). For ty-two (82.4%) had mediastinal lymphadenopathy, and more than half the tumo rs (60.8%) were at an advanced stage [IIIB (n=11) or IV (n=20)]. The averag e delay in diagnosing lung cancer was 11.7 (range, 1-24) months, and the ca uses of this were failure to observe new nodules masked by coexisting stabl e TB lesions (n=8), misinterpretation of new lesions as aggravation of TB ( n=5), misinterpretation of lung cancer as tuberculoma at initial radiograph y (n=4), masking of the nodule by an active TB lesion (n=3), and subtleness of the lesion (n=1). Conclusion: Most cancers concurrent with TB are large, lobulated masses wit h mediastinal lymphadenopathy, indicating that the morphologic characterist ics of lung cancer with coexisting pulmonary TB are similar to those of lun g cancer without TB. The diagnosis of lung cancer is delayed mainly because of masking by a tuberculous lesion, and this suggests that in patients in whom a predominant or growing nodule is present and who show little improve ment of symptoms despite antituberculous or other medical therapy, coexisti ng cancer should be suspected.