What are the differentials for this case?
The left pleural effusion and associated lung can have many aetiologies but in this case, the collapsed left lower lobe has an ill-defined hypovascular area that is suspicious for an underlying focal lesion. As the patient is not septic, this became concerning for underlying malignancy. Pleural tap with cytology has been recommended.
There is a large left pleural effusion with partial collapse of the lung. Within the LLL collapsed lung, there is an ill-defined hypovascular mass that is highlighted in the normal enhancing collapsed lung.