In certain cases pleural adenocarcinoma can behave like a primary tumour of the pleura. If the origin of this type of tumour is not clearly established, the macroscopic aspect of the pleura explored by thoracoscopy enables a distinction to be made between isolated disease of the parietal pleura and mixed disease of both the parietal and visceral pleura. The object of this study was to evaluate the prognosis of tumour disease of the visceral pleura. Using a murine model (the nude mouse) of cancer of both visceral and parietal pleura induced by implanting histologically intact human carcinoma, we have compared the symptoms of survival of the two groups of mice as well as the local and regional dissemination and metastases of the implanted tumour. The growth of the tumour was suspected by the appearance of weight loss, signs of respiratory difficulty and/or cachexia. Autopsy examination allowed a measure of the size of tumour dissemination. A pleural cancer, histologically identical to the initial human tumour with invasion of the neighbouring structures as one sees in man, was obtained in all the implants. Nevertheless, contralateral mediastinal lymph node metastases were only found in mice with implants on the visceral pleura. The median survival was 27.9 days and 31 days respectively for implanted mice on the visceral pleura and on the parietal pleura. Mice with implants on the visceral pleural lost more weight than those implanted on the parietal pleura (p < 0.001). The results of this study show that the models of parietal pleura and visceral pleura each correspond to an early stage disease and to a stage of advanced disease.(ABSTRACT TRUNCATED AT 250 WORDS)