Parietal Pleural Lymphatic Blockage by Anthracotic Nodule Laden Macrophage, Leading Cause of Pleural Effusion in Anthracosis.

Anthracosis of lung is assumed to be a disease that causes parenchymal accumulation of macrophage-laden anthracotic nodules, which leads to bronchial obstruction, lung mass, and lymphadenopathy. Pleural surface anthracosis involvement as extra-parenchymal involvement has been rarely reported. Still, due to presentation with a transudate pattern, pleural effusion is considered to be a side effect of lung collapse. I represent two subjects with patches of anthracosis in the presumptive place of anatomical fenestra of lymphatic vessels in the parietal pleural. It may cause inhibition of reabsorption of pleural fluid and finally accumulation of transudate pleural effusion. Involvement of the pleura by anthracosis, and black discoloration of the parietal pleura have already been discovered by physicians who perform pleuroscopy. The pleural involvement by anthracosis is usually diffuse. In these two subjects, pleural involvement was in the early stage of anthracosis, which helped me to introduce a new mechanism for transudative pleural effusion due to blockage of the pleural lymphatic channels entrance.