anatomical basis of pleural effusion

ABSTRACT

Pleural effusions associated with pulmonary diseases or malignancy emphasise the absorptive efficiency of the pleura. This review focuses attention on the major role of the lymphatic drainage system in absorbing fluids from the pleural cavity. Mesothelial cells of the diaphragmatic pleura in particular overlie a rich plexus of lymphatic lacunae strategically located within the submesothelial connective tissue. The existence of patent stomata between mesothelial cells of the diaphragm ensures continuity between the pleural cavity and the lymphatic lacunae. These pleurolymphatic stomata are exclusive to the diaphragm and may serve as the main drainage channels for absorption of particulates, pathogens and tumour cells from the pleural cavity. Pleural effusion may develop when production of pleural fluids exceeds the capacity of the lymphatic system and when inflammation or malignant infiltration involves any component of this drainage system