A biopsy is a diagnostic procedure in which a doctor removes cells or tissues for further testing, often in attempting to discern the presence of a disease. While there are several types of biopsies, the initial test for mesothelioma often involves a needle aspiration biopsy. During this test, a needle is inserted into the affected area and a fluid or tissue sample is taken by a surgeon, radiologist, or pulmonologist.
The needle biopsy is a closed procedure, less traumatic and safer than an open surgical or excision biopsy, usually requiring only a local anesthetic. No incision is necessary, and usually the only complications are bruising, soreness, and light bleeding at the biopsy site. The site and extent of the biopsy depends on the location of the suspected tumor and the severity of the patient’s symptoms.
In this kind of biopsy, a needle is inserted into the pleural cavity, which is the lining that surrounds the lungs. Between two layers of pleura exists a small amount of pleural fluid, and a biopsy here involves the removal of a small amount of this fluid or surrounding membrane. These cells are then taken to the lab to test for the presence of mesothelioma or other diseases.
A thoracentesis is similar to a pleural biopsy, but generally involves a larger, hollow needle called a cannula and the removal of a greater amount of fluid. In addition to gathering cells for diagnostic testing, this procedure also relieves the pressure caused by a build-up of fluid in the pleura, a condition called pleural effusion. The removal of this fluid can improve lung function and greatly lessen the patient’s discomfort.
Paracentesis is the procedure for draining fluid from the peritoneal cavity in the abdomen. Like the thoracentesis, this procedure performs the dual purpose of collecting cells and fluid for testing and relieving the pressure of any built-up fluid. This build-up is called ascites or hydroperitoneum, and can be a symptom of peritoneal mesothelioma or other cancers.
While it is rare for mesothelioma to develop in the pericardium – the sac surrounding and cushioning the heart – it has been known to happen. In this case, a physician may decide to drain fluid from this sac for testing or to ease discomfort, a procedure known as pericardiocentesis.