NCIt definition : A collection of fluid in the pleural cavity resulting from malignant disease. Malignant
pleural effusions often contain free-floating malignant cells.;
Alternative definition : NCI-GLOSS: A condition in which cancer causes an abnormal amount of fluid to collect
between the thin layers of tissue (pleura) lining the outside of the lung and the
wall of the chest cavity. Lung cancer, breast cancer, lymphoma, and leukemia cause
most malignant pleural effusions.;