[Short and long term behaviour of pleural effusion cultures. (Report of 200 cases) (author's transl)].

Pleural effusions from 200 patients with benign or malignant pleural involvement have been cultured in vitro and observed from 48 hours to 9 months. The morphology and "social behavior" of the different types of cells are described. Mesothelial cells settle down quickly and come into contact with each other by long cytoplasmic processes. The tendency of epithelial malignant cells is to clump and grow in clusters. These "balls" of varying size are freed into the culture medium. Similar clusters may be found in benign effusions showing mesothelial hyperplasia. In case of malignant primary tumor of the pleura, the morphology of cultured cells is similar to that of mesothelial cells. In 3 cases, typical malignant epithelial cells have allowed us to discard the diagnosis of malignant mesothelioma. Discrepancies between conventional cytology and cell culture were found in 13 cases: in 6 cases, positive for malignant cells using conventional cytology, cell culture was negative. In 7 cases with negative routine techniques, cell culture disclosed malignant cells. Large multinucleated syncytia were observed in 15 cultures. They suggest a cytopathic effect similar to that seen in myxovirus infected cells. Correlation with the etiology of pleural effusions in these cases is described.