This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lung Tumor, Subject name: Pathology
[{'content': 'A 27-year-old man with history of alcoholism and repeated bouts of aspiration pneumonia comes to the emergency room with a high fever and pleuritic chest pain. Physical examination reveals dullness on percussion and absence of breath sounds in the right lower lung field. A chest X-ray demonstrates pleural fluid on the right side. Thoracentesis returns a thick, foul-smelling fluid. Which of the following is the most likely diagnosis? \nSelect and explain. \nA. Chylothorax, B. Empyema, C. Hemothorax, D. Pneumothorax', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pleuritis (inflammation of the pleura) may result from the extension of any pulmonary infection to the visceral pleura. Pyothorax refers to a turbid effusion containing many neutrophils. Empyema is a variant of pyothorax in which thick pus accumulates within the pleural cavity, often with loculation and fibrosis. Hydrothorax refers to transudation of edema fluid into the pleural cavity.', 'role': 'assistant'}]