A pleural tumor is more frequently metastatic cancer (cancer that has spread from the place where it first started to another place in the body) than mesothelioma. It is important to distinguish between the two, because they have vastly different treatment options.

It is also important to distinguish which sub-type of mesothelioma a patient has (epithelioid, sarcomatoid or Biphasic/mixed). The different kinds are determined by the pathologist who looks at the tumor tissue under the microscope. Epithelioid mesothelioma is the more favorable subtype of mesothelioma and carries a greater chance of survival after surgery and multi-modality therapy. Sarcomatoid mesothelioma is composed of spindle-shaped cells, and these tumors tend to have a less favorable outcome. Surgery is typically not offered for patients with sarcomatoid mesothelioma.

Radiologic Tests

There are a number of radiologic tests that we order while trying to establish the diagnosis and the stage (how advanced the cancer may be), and determine if surgery is feasible and in the best interest of the patient.

  • CT scans of the chestc can reveal the pleural abnormalities suggesting mesothelioma, but a biopsy is needed to make a definitive diagnosis.
  • PET scans help determine if there is any suggestion of disease in the other lung, in the abdomen or in other areas of the body
  • MRI can suggest invasion into the chest wall, mediastinum or across the diaphragm into the abdomen

Invasive Diagnostic Tests


A needle or small catheter is used to drain fluid from the pleural space. The fluid is sent for analysis to a pathologist to see if cancer cells are present. It is not uncommon that the pleural fluid is analyzed and does not indicate a diagnosis of mesothelioma, or even cancer at all – even if cancer is present in that space.

CT scan

The most common approach is a video-assisted thoracoscopic biopsy, or VATS. Through a very small incision in the chest wall, a videoscope is introduced into the pleural space and multiple biopsies are taken of the pleural surfaces (VATS pleural biopsy). This often results in a definitive diagnosis of mesothelioma. This procedure should be performed by a thoracic surgeon with experience in treating mesothelioma.