Which of the following is a type of pleural effusion identified in pathology?

Transudative effusion is indeed a well-recognized type of pleural effusion in pathology. It is characterized by the accumulation of fluid in the pleural space that typically results from systemic conditions, such as heart failure or cirrhosis, where the pleura itself is not significantly involved. The fluid in transudative effusions is generally clear and has a low protein content and low specific gravity.

These effusions are distinct from exudative effusions, which occur due to local factors like infection or malignancy, leading to fluid with a higher protein concentration. Distinguishing between transudative and exudative effusions is vital for diagnosis and management, often achieved using Light's criteria, which assess the protein and lactate dehydrogenase levels in the pleural fluid.

The other types mentioned, such as intraductive effusion and cystic effusion, are not recognized classifications of pleural effusions in standard pathology terminology. Hemorrhagic effusion refers to a pleural effusion containing blood, which can occur due to trauma or malignancy, but it is not a primary classification within the context of how pleural effusions are usually categorized. Therefore, transudative effusion stands out as the