Mesotheliomas of the pleura

: The materials concerning 19 patients with pleural mesotheliomas are analysed. The patients were subdivided into three groups according to the clinico-roentgenological picture and course of the affection: 1) four patients in whom pleural mesothelioma proceeded without exudate accumulation; 2) seven patients in whom exudate accumulation in the pleural cavity was the main sign of the tumor; 3) 8 subjects in whom the tumor developed on the side of an artificial pneumothorax many years following its cessation. Among 19 patients only in 5 cases the tumor was suspected soon after their admission to the hospital. A needle biopsy of the pleura is felt to be the most effective method of diagnosis of pleural mesotheliomas, whereas in failure of the former -- pleuroscopy.