Q: You were surprised with black colored pleural effusion on thoracentesis. What are your differential diagnosis?

Answer:

• infection with Aspergillus niger
• infection with Rizopus oryzae,
• malignant melanoma,
• non-small cell lung cancer 
• ruptured pancreatic pseudocyst,
• charcoal-containing empyema

Reference:

Saraya T, Light RW, Takizawa H, Goto H. Black pleural effusion. Am J Med. Jul 2013;126(7):641.e1-6.