Long-term tissue cultures of human pleural effusions: a cytological follow-up.

A cytological follow-up was performed on long-term cultures of 53 metastatic pleural effusions and 34 cases of mesothelial hyperplasia. Cells were grown in Leighton tubes with up to 11 changes of cover slip in the same tube. Cell morphology and arrangement was followed for up to 1 year. Morphological criteria are of no use in recognizing malignant cells with any degree of certainty. As to cell distribution, several types of heaping up are observed both in benign and malignant pleural effusions. In malignant cases, patches of cells in an epithelial-like arrangement are seen heaping up from their substrate. They can be recovered from the used medium by cytocentrifugation. Such behavior may explain the numerous unsuccessful attempts to establish epithelial cell lines, as the clusters of epithelial cells are progressively lost in the supernates.