[Thoracoscopic anatomy, significance of pathologic findings in thoracoscopic open lung biopsy, and pleural mesothelioma].

To better understand diseases of the thoracic space, pathologic findings of thoracoscopic open lung biopsy are described based on thoracoscopic anatomy and pleural mesothelioma. A positive colloidal iron stain in the plasma membrane of the mesothelial cells indicates the presence of hyaluronic acid, which appeared to decrease the friction between the lung and thoracic cavity. Excess fluid in the pleural cavity was removed from specific sites in the parietal pleura with stomas. We evaluated the pathologic features of 57 video-thoracoscopic open lung biopsies. Specific diagnoses were established in 89%, and of these half were pneumothorax. Nonspecific pathologic changes were found in 11%, of which interstitial pneumonia was the most common. This procedure is useful in taking a large number of specimens for diagnosis, and to evaluate the degree and progress of fibrosis. The differential diagnosis of mesothelioma from pulmonary adenocarcinoma, reactive mesothelial hyperplasia, and sarcoma of the pleura are described. Also, to understand mutations of the p53 tumor-suppressor gene in mesothelioma, mesothelial lesions were studied with immunostaining for p53 antibody (DO-7) and with in situ hybridization for p53 mRNA. In immunohistochemical staining for DO-7, all reactive mesothelial cells were positive, and 75% of mesotheliomas including epithelial, biphasic, and sarcomatous types were positive, and 75% of mesotheliomas including epithelial, biphasic, and sarcomatous types were positive. mRNA for p53 was expressed in all reactive mesothelial cells, and in 55% of allmesotheliomas.