Because healthy mesothelial tissue produces a lubricating fluid, when this tissue turns cancerous it often produces too much fluid. This can lead to pleural effusion in pleural mesothelioma or ascites in peritoneal mesothelioma.

Pleural Effusion and Ascites

One common symptom in mesothelioma is fluid or water retention in specific areas of the body. If a scan reveals a fluid build-up around the lungs this is called pleural effusion. Pleural effusion is generally defined as excess fluid that fills the pleural cavity. The added pressure of this fluid can make breathing difficult. If a scan reveals fluid build-up around the abdomen this is called ascites. Both types of fluid build-up are one indicator of possible mesothelioma. Clinicians often drain these fluids to provide relief to patients. The fluid can then tested to determine if it contains any cancer cells.

Removing Fluids for Testing

If there is a buildup of fluid, a sample can be removed by inserting a thin, hollow needle through the skin and into the fluid. This may be done in a doctor’s office or in the hospital. Sometimes ultrasound (or an echocardiogram) is used to help guide the needle. This procedure is generally called a fine-needle aspiration or aspiration biopsy. This procedure also has specific names depending on where the fluid is being removed. For example removing fluid from the:

  • Chest = Thoracentesis
  • Abdomen = Paracentesis
  • Area around the heart = Pericardiocentesis

The fluid is then transferred to a pathologist. The pathologist looks at the sample under a microscope to see if it contains cancer cells. If cancer cells are found, additional tests might be performed to identify the type of cancer. However, testing the fluid alone is not considered sufficient in most cases. Most doctors prefer to employ the “gold standard” – a tissue biopsy.