Abstract
Thoracoscopy is an old but still very valuable technique for the evaluation of pleural pathology and, especially for the further investigation of the aetiology of pleural fluid. It remains of great importance, since it is able to not only provide an exact diagnosis, but also can have therapeutic potential. In this review, the differential diagnostic aspects of transudate versus exudate are further elaborated, and the role of thoracoscopy is compared to closed pleural biopsy and image guided biopsy.