How can a pleural process be differentiated from an extrapleural process?

Differentiation can be difficult. If the center of the lesion is inside the chest wall, a pleural process is likely. Rib destruction indicates extrapleural extension and possibly the origin of the mass. CT can be most definitive.

I HATE pleural calcification.

Hemothorax (previous)
Asbestos exposure
Tuberculosis (previous), talc pleurodesis
Empyema (previous)