Black pleural effusion.

BACKGROUND: Black pleural effusions are extremely rare and have been reported in patients with infection, malignancy, and hemorrhage. However, no review articles appear to have focused on this rare clinical presentation.

PURPOSE: To classify and characterize diseases causing "black pleural effusion" based on the pathophysiological mechanisms involved.

METHODS: We searched the medical literature to find reports of "black pleural effusion" using the PubMed database.

RESULTS: We identified 8 cases and classified the underlying diseases into the following 4 entities based on pathophysiological conditions: 1) infection (Aspergillus niger and Rhizopus oryzae); 2) malignant melanoma, in which cells contain melanin pigment; 3) hemorrhage and hemolysis associated with non-small cell lung cancer or rupture of a pancreatic pseudocyst; and 4) other causes (charcoal-containing empyema). Discrimination between biliopleural fistula and pancreatico-pleural fistula, which also mimicking in color, was easily achieved by focusing on pleural amylase levels, elevation of pleural indirect bilirubin, presence of pleural glycoholic acid, and the predominant site of pleural effusion.

CONCLUSION: Black pleural effusions can be divided into 4 major categories based on the underlying pathophysiological conditions.