Mesothelioma diagnosis is obtained with careful and thorough assessment of radiological and clinical findings, as well as a confirmed tissue biopsy. There should be a review of the person's medical history, an extensive physical exam, chest and abdomen X-ray and a history of asbestos exposure. At the same time, an MRI or a CT scan may be done. If these preliminary tests reveal any suspicion of mesothelioma, it is essential to confirm the diagnosis through a biopsy. (Learn about the common mesothelioma symptoms.)

 

The Value of Imaging Techniques in the Diagnosis and Assessment of Mesothelioma
Various imaging techniques prove useful when there is suspicion on malignant mesothelioma because of the presence of pleural effusion plus a history of secondary or occupational asbestos exposure. While the imaging techniques may be very valuable in the assessment of the possibility of cancer, authoritative diagnosis is still often ascertained through tissue biopsy or fluid diagnosis.
These are some of the most common imaging methods.
• X-ray – A chest X-ray reveals fluid build up (pleural effusion) which is confined to either right or left lung. Probabilities are 60% on the right lung and 40% on the left; and a mass may be found on some occasions. Some signs of prior asbestos diseases that are non-cancerous may also be found. These may be pleural plaques or calcifications, or scarring as a result of asbestosis.

• CT (Computed Tomography) Scan – CT scans can define pleural effusion, thickening, calcification as well as the thickening of interlobular fissures or possible invasion of the chest wall. Computed Tomography however, will not be able to manifest the difference between mesothelioma and lung adenocarcinoma which could have scattered to the pleura. For tissue diagnosis, CT scans may be very useful in directing fine needle aspiration of pleural mass.

• MRI (Magnetic Resonance Imaging) – MRI scans are commonly used to determine the degree of tumor before the aggressive treatment. They provide images in many planes that is why they can better identify tumors as compared to normal structures. CT scans are more accurate in assessing growth of lymph nodes that lie between the lungs (mediastinal) and clear diaphragmatic surface. These two play an essential role in surgical candidacy.

• PET (Positron Emission Tomography) – This imaging method is now becoming a vital part of the evaluation and diagnosis of evaluation. PET scans are more costly than other kinds of imaging techniques and does not always have insurance but they are believed to be the most analytical of tumor sites and the most superior in identifying mesothelioma staging. There are further explanations about PET scans here.

• PET / CT – This is a combination of PET (Positron Emission Tomography) and CT (Computed Tomography). For mesothelioma patients who are recommended for aggressive multimodality treatment (chemotherapy, surgery and radiation), precise clinical staging is exceedingly important. Incorporated PET / CT imaging has a fairly new tool and has become the preferred imaging method for identifying surgical eligibility. By combining the advantages of PET and CT (metabolic and anatomic information) into one scan, this technology more accurately determines the stage of mesothelioma. This can help identify the best option for treatment of the patients. You can read more about the study of PET – CT imaging techniques in preoperative assessment of patients having malignant pleural mesothelioma.

Needle biopsy of a mass, or the removal and test of fluid around the lung can be used to diagnose mesothelioma. But these samples are often insufficient in determining whether it is epithelial, sarcomatous or mixed cell type. Sometimes also fluid diagnosis is unreliable. Because of these, open pleural biopsy might be advised. In this process, the surgeon makes a tiny incision though the wall of the chest and inserts a lighted thin tube known as thoracoscope in the chest between the ribs. Then he will remove a tissue sample for review under a microscope which is done by a pathologist. In peritoneal biopsy, the surgeon will make an incision in the abdomen and will insert a peritoneoscopic to the abdominal cavity.

When there is suspicion of mesothelioma as revealed by the imaging tests, it will be confirmed by pathological exams and a pathology report is issued. This will be the last stage in this process which started with symptoms that led patients to visit the doctor. Symptoms may be a build up of fluid (also called pleural effusion), shortness of breath, chest pains or swelling of the abdomen, in which case a doctor may recommend a CT scan or X-ray of the chest and abdomen. The following tests may be undertaken if further tests are needed:

- VATS (Video-Assisted Thoracoscopic Surgery
The use of VATS is one of the most common tools in diagnosing mesothelioma. Biopsies of pleural masses, lining, nodules and pleural fluid can be easily be acquired using this least invasive procedure. Concurrently, other therapies can be done, such as talc (pleurodesis) for pleural effusions. The patient will be under general anaesthesia and several "ports" or small incisions will be made through the wall of the chest. The surgeon inserts a tiny camera as well as other surgical instruments, through a scope, into an incision, to take back tissue samples into other incisions. The surgeon will view the camera images through a video screen to complete the necessary procedures.
In other cases, this technique replaces thoracotomy, which needs a larger incision to access through the chest cavity. And because VATS is much less invasive, there is lesser post-operative pain for the patient and hopefully shorter period of recovery.

- Thoracoscopy
The doctor may need a special instrument known as thoracoscope for pleural mesothelioma. He needs it to look within the chest cavity. A cut is made through the wall of the chest and the thoracoscope is put into the chest, amid two ribs. This is usually done with a local anaesthesia or painkiller. If the doctor found some fluid collected inside your chest, he may drain it by inserting a needle in your chest and use a suction to remove the fluid gently. This procedure is called thoracentesis.

- Peritoneoscopy
This is for peritoneal mesothelioma where the doctor uses the special tool peritoneoscope to look within the abdomen. This instrument is inserted through an opening made in the abdomen. This is also done with local anaesthesia or painkiller. Same as with the lungs, collected water in the abdomen has to be drained by putting into the abdomen and gently suction it to remove the fluid. Paracentesis is the term used for this process.

- Biopsy
If the surgeon found any abnormal tissue, he will cut out a small piece and have it verified under a microscope. Usually, this is done during the process of thoracoscopy or peritoneoscopy, but may also be made during surgery.

What is Pathology? What is the Role of Pathologists in the Process of Diagnosis?
Pathology is the study of fluid, cells, and tissue taken from the patient's body. Pathology plays a very vital part in the diagnosis of mesothelioma; its significance cannot be underestimated because the entire course of treatment is reliant on an accurate diagnosis. Majority of hospitals have pathology laboratories with licensed technologies and board-certified pathologists.
Pathologists make diagnosis by examining the tissue under a microscope. Based on some established criteria, they will determine if the cells are benign or malignant. Consequently, the type of cancer disease is determined. Generally, pathologists have an expertise on various diseases but a few are trained in a subspecialty like mesothelioma. These are doctors who are recognized world-wide as premier experts and have made highly acclaimed research papers, have published abstracts and articles and have acquired some experiences on teaching. You may call MW toll-free at 1-8777-367-6376 for a list of pathology experts in the field of mesothelioma. Also, you may check out this site for more details on tissue processing.
Knowledge of the stage of mesothelioma is a great factor in assisting the doctor in formulating a treatment plan. If the cancer is limited to the pleura, the cancer can be considered localized; if it has scattered beyond the pleura to several parts of the body like the chest wall, lungs, lymph nodes or abdominal cavity.