[A histopathological study of 102 autopsy cases of primary lung cancer with respect to pleural carcinomatosis].

Visceral pleural lesions in primary lung cancer were studied histopathologically in 102 autopsy cases. Pleural carcinomatosis was defined as the presence of cancer cells in the visceral pleura and/or pleural space. Ipsilateral and contralateral pleural carcinomatosis in the primary lung cancer were compared. They were found to be similar in that both were closely related with cancer cell infiltration of blood vessels in the lung parenchyma, lymphangiosis carcinomatosa in the lung parenchyma and multiple extrathoracic organ metastases. However, differences were observed. In the ipsilateral visceral pleura, cancer cells were thought to infiltrate the interstitium in the vascular layer of the visceral pleura from lymphatic vessels in the vascular layer of the visceral pleura with the following frequency; 3.6:8.52:6.52:1. In the contralateral visceral pleura, however, cancer cells were thought to infiltrate the interstitium in the vascular layer of the visceral pleura from lymphatic vessels in the vascular layer of the visceral pleura, the pleural space, the subpleural lung parenchyma and blood vessels in the vascular layer of the visceral pleura with the following frequency; 4:1.9:12.25:1. Disruption of the elastic layer of the visceral pleura was also studied. Twenty-eight of 66 pleural carcinomatosis cases showed no disruption of the elastic layer, and greater than 1-mm disruption was found in only 7 cases. The author thought that the disruption in these few cases was related to the manner of cancer-cell infiltration of the visceral pleura. When cancer cells spread to the visceral pleura from the lung parenchyma, they lost intercellular adhesiveness in four adenocarcinoma cases. Thus we suspected that cancer cells lost intercellular adhesiveness and became single cells or small cancer nests when infiltrating the visceral pleural from the lung parenchyma, and single cells or small cancer nests entered through the elastic layer of the visceral pleura. Therefore only small disruptions are found in the visceral pleura of pleural carcinomatosis cases.