The role of pleural biopsy in the diagnosis of pleural tuberculosis.

<bold>Introduction:</bold> Diagnosing pleural tuberculosis (pTB) is challenging due to low sensitivity in conventional microbiological methods. Treatment initiation decisions are often based on a possible/probable diagnosis. A confirmed diagnosis may involve identifying <italic>Mycobacterium tuberculosis</italic> in direct or cultural examination of pleural products. Pleural biopsy (PB) performed by pleuroscopy is not widely available in most countries. <bold>Objective:</bold> To assess the utility of closed-needle PB in the diagnosis of pTB. <bold>Methods:</bold> Retrospective observational study of patients diagnosed with pTB who underwent thoracentesis between 01/2010 and 12/2023 in our department. Demographic, clinical, and laboratory data were analyzed. When available, results of direct, cultural and histological examination of PB were also analyzed. <bold>Results:</bold> 38 patients were studied, with 28 (73,7%) being male and an average age of 42.7 years. A confirmed diagnosis of pTB was possible in 34.2% of cases, while the remaining 65.8% initiated treatment based on a probable diagnosis. In 2 cases, pleural fluid (PF) analysis was not possible due to complications in thoracentesis. Pleural biopsy was conducted in 28 (73,7%) patients. All PF samples were exudates, 86.1% had a lymphocytic predominance and 88.8% had ADA levels above 30 IU/L (average was 69.2 IU/L). PF cultures were positive in 22.2%. Regarding PB, histological examination suggested pTB in 92.9% of cases. A positive PB culture was the confirmation method in 46.2% patients with confirmed pTB. <bold>Conclusion:</bold> Definitive diagnosis was not possible in most cases. Even though outdated, closed-needle PB and pleural samples cultures remain a useful diagnostic test in settings where pleuroscopy is not widely available.