12th May 2024

A 70-year-old man presents with chest pain, a persistent cough producing blood-tinged sputum, and shortness of breath.

A 70-year-old man presents with chest pain, a persistent cough producing blood-tinged sputum, and shortness of breath. He has a history of asbestos exposure and a 40-year history of smoking. A CT scan reveals a mass in the left lower lobe of the lung, and a biopsy confirms non-small cell lung carcinoma. Further imaging indicates pleural effusion and thickening.

Which is the most likely route by which this tumour spread to the pleural cavity?