pleural biopsy

When the fluid drawn from the chest does not give a clear answer, the next step is to examine the pleura itself. A pleural biopsy is the act of taking a small piece of the pleural lining so a pathologist can look at the tissue under the microscope and identify what is wrong.

There are gentler and more thorough ways to do it. A needle can be passed through the chest wall to grab a sliver of pleura, best done under image guidance to aim at thickened areas. The more reliable approach is thoracoscopy (medical or surgical keyhole inspection), in which a camera lets the operator see the pleural surface directly and take targeted samples — far more sensitive for patchy disease such as cancer or tuberculosis.

The two diagnoses that most often justify a biopsy are malignancy (including mesothelioma, where tissue, not fluid, is usually needed for certainty) and tuberculous pleuritis. Because it samples tissue rather than just fluid, a pleural biopsy can both confirm a diagnosis and provide material for the molecular tests that increasingly guide cancer treatment.