Transthoracic needle aspiration biopsy: value in the diagnosis of mycobacterial lung opacities.

The purpose of this study was to assess the value of transthoracic fine-needle aspiration in the diagnosis of mycobacterial infection as the cause of focal lung opacities. Six hundred twelve fine-needle aspiration biopsies were performed from 1985 to 1997 in 587 patients with solitary or multiple lung opacities. Initial procedures, including sputum analysis and bronchoscopy, had been nondiagnostic. Fluoroscopic or computed tomography guidance was used, and a pathologist was present. A diagnosis of mycobacterial infection was established when acid-fast bacilli were demonstrated in the aspirate. In 487 patients, a malignant cause was confirmed, and six other patients had carcinoid tumor. Of 94 nonmalignant opacities, 24 (26%) were determined to have a mycobacterial cause. Fine-needle aspiration biopsy detected acid-fast bacilli in 15 of 24 cases (sensitivity, 62.5%; specificity, 100%). Radiologic findings included upper lobe involvement (17 of 24 cases), single opacities (12 of 24 cases), satellite nodules (4 of 12 cases with single opacities), irregular borders (19 of 24), eccentric calcification (2 of 24), and cavitation (8 of 24). The authors conclude that fine-needle aspiration biopsy must be processed for acid-fast bacilli when nonmalignant cytologic findings result, even if the results of sputum smears, cultures, and bronchoscopy are negative.