Endobronchial tuberculosis: histopathological subsets and microbiological results

Background: Endobronchial tuberculosis (EBTB) is defined as a tuberculous infection of the tracheobronchial tree with microbial and histopathological evidence, with or without parenchymal involvement. Bronchoscopic appearances of EBTB have been divided into seven subtypes: actively caseating, edematous-hyperemic, fibrostenotic, tumorous, granular, ulcerative, and nonspecific bronchitic. However, information for establishing a definite microbiological diagnosis in each of these categories is lacking. We aimed to present bronchoscopic appearances and percentages for the EBTB subtypes and to compare bronchoscopic appearances with microbiological positivity in bronchial lavage fluid. Methods: From 2003 to 2009, 23 biopsy-proven EBTB patients were enrolled in the study. Diagnosis of EBTB was histopathologically confirmed in all patients. Results: The commonest subtype was the edematous-hyperemic type (34.7%); other subtypes in order of occurrence were: tumorous (21.7%), granular (17.3%), actively caseating (17.3%), fibrostenotic (4.3%), and nonspecific bronchitic (4.3%). Although all patients were sputum-smear-negative for acid-fast bacilli (AFB), 26% of patients were smear-positive for AFB in the bronchial lavage fluid. The bronchial lavage fluid grew Mycobacterium tuberculosis in 39.1% of all patients. The bronchial lavage smear positivity for AFB in the bronchial lavage fluid was 75%, 25%, 20%, 12.5%, 0%, and 0% for the granular, actively caseating, tumorous, edematous-hyperemic, fibrostenotic, and nonspecific bronchitic subtypes of EBTB, respectively. Culture positivity for Mycobacterium tuberculosis in bronchial lavage fluid was 75%, 50%, 40%, 25%, 0%, and 0%, respectively. Conclusion: The commonest subtype of EBTB was the edematous-hyperemic subtype. The granular type had the highest smear positivity and culture positivity for Mycobacterium tuberculosis in bronchial lavage fluid. Bronchoscopy should be performed in all patients suspected to have EBTB.