Diagnosis
A diagnosis of mesothelioma is most often obtained with a careful assessment of clinical and radiological findings in addition to a confirming tissue biopsy. Following are some of the tests your specialist may recommend and their value in diagnosing and assessing mesothelioma.Computed Tomography (CT)CT scans are able to define pleural effusion, as well as pleural thickening, pleural calcification, thickening of interlobular fissures or possible chest wall invasion. CT, however, is not able to differentiate between changes associated with benign asbestos disease, or differentiate between adenocarcinoma of the lung versus mesothelioma. CT scans may also be of value in guiding fine needle aspiration of pleural masses for tissue diagnosis. This scan usually takes 10-30 minutes, but may vary according to the patient.
Magnetic Resonance Imaging (MRI)MRI scans are most often used to determine the extent of tumor prior to aggressive treatment. Because they provide images in multiple planes, they are better able to identify tumors as opposed to normal structures. They are also more accurate than CT scans in assessing enlargement of the mediastinal lymph nodes which lie between the two lungs, as well as a clear diaphragmatic surface, both of which play an important role in surgical candidacy. An MRI scan usually takes 20-40 minutes, but may vary according to the patient.
Positron Emission Tomography (PET)PET imaging is now becoming an important part of the diagnosis and evaluation of mesothelioma. PETs are considered to be the most diagnostic of tumor sites, as well as the most superior in determining the staging of mesothelioma. Because PET scans are relatively new and may not be available in all locations, it may be necessary to travel to a specialized center to have one.
Fluid AnalysisTesting of the pleural fluid for malignant cells is considered to have limited value in diagnosing mesothelioma. Diagnostic thoracentesis, in which cells are extracted from the pleural cavity, is commonly done when the possibility of mesothelioma exists. Unfortunately, negative or inconclusive readings account for nearly 85% of all fluid tested. Even in the event of a positive fluid report, doctors may opt to perform a confirming tissue biopsy as long as it is not detrimental to the patient’s health.
Tissue Analysis (Biopsy)In most cases, it is ultimately a needle biopsy of the pleura, or an open surgical biopsy, that yields a confirmed diagnosis of mesothelioma. In a pleural biopsy procedure, the surgeon will make a small incision through the chest wall and insert a thin, lighted tube called a thorascope into the chest between two ribs. He will then remove a sample of tissue to be reviewed under a microscope by a pathologist. In a peritoneal biopsy, the surgeon makes a small incision in the abdomen and inserts a peritoneoscope into the abdominal cavity.
