What is the most likely cause of a large unilateral pleural effusion in a 70 year old patient?

Question

Quizplus · Accepted Answer

While all of the options listed can lead to a pleural effusion, malignancy is the most likely cause in a patient of this age. Other factors, such as smoking and prior radiation therapy, can also increase the likelihood of developing a pleural effusion due to malignancy. While a chest x-ray may show a pleural effusion, further testing such as a biopsy may be needed to determine the underlying cause.

What Is the Most Likely Cause of a Large Unilateral