Pathophysiology of Malignant Pleural Effusion

The tumours most commonly associated with malignant pleural effusions are:

• Lung
• Breast
• Lymphoma
• Tumours of the GI tract

Tumour cells migrate to the pleura by either haematogenous or lymphatic spread. This can occur from a primary site in the lung or via metastases from distant sites.

Tumour cells disrupt the network of lymphatic channels within the parietal pleura causing obstruction. Effusions associated with malignancy are therefore exudates.