The mesothelium is composed of mesothelial cells, which provide a protective surface and play a role in a number of processes such as fluid transport, inflammation, and tissue repair. The mesothelium lines the pleural, peritoneal, and pericardial cavities, as well as the testicles. Malignant mesothelioma is an aggressive cancer in the lining of the lungs or abdomen. This cancer starts in a thin layer of protective tissue called the mesothelium that lines several major body cavities and covers most of the body’s internal organs.
When asbestos fibers are inhaled or ingested, they can enter the mesothelium and injure the mesothelial cells, eventually giving rise to malignant tumors. Then cells of the mesothelium undergo changes that become malignant, they can spread to other parts of the body. Mesothelioma can start in the membrane surrounding the lungs, heart or abdomen, with the lungs being the most common site of the disease.
Unfortunately, mesothelioma undergoes a very prolonged latency period, so symptoms of the disease may not appear for decades (up to fifty years) after the asbestos exposure has occurred. It’s this delay in obvious onset that produces the low (5% to 10%) five-year survival rate.
Mesothelioma: Read About Symptoms, Types and Diagnosis
Types of Mesothelioma Cancers
The most common type of the cancer is malignant pleural mesothelioma, which affects the pleura — the mesothelial membrane lining the lungs and chest wall.
Mesothelioma that begins in the pleura typically results from asbestos fibers being inhaled. Tumors that develop in the pleura may spread to the nearby diaphragm, heart, and blood vessels of the chest.
When it develops in the peritoneum, the mesothelial membrane that covers the abdominal cavity and the organs within it, the cancer is called peritoneal mesothelioma (or abdominal mesothelioma). Peritoneal mesothelioma may result from swallowing asbestos fibers or inhaling fibers that then work their way into the abdomen. Patients with malignant peritoneal mesothelioma often experience abdominal swelling due to fluid build-up accompanied by abdominal pain, weight loss, and loss of appetite.
The pericardium is the mesothelial membrane covering the heart. Pericardial mesothelioma is a highly lethal and very rare form of the cancer. Fluid in the pericardial space, shortness of breath, fever, chest pain, weight loss, and heart palpitations are symptoms of pericardial mesothelioma.
The rarest of all types, mesothelioma of the tunica vaginalis testis (testicular mesothelioma) is a tumor of the membrane covering the testicle. Because of its rarity, there is little clinical agreement about testicular mesothelioma characteristics and symptoms, making diagnosis extremely difficult. Patients sometimes report painful swelling of the testicle, and a doctor diagnoses the cancer intra-operatively (during surgery) or post-operatively, following laboratory analysis.
Signs and symptoms
Symptoms of malignant pleural mesothelioma, the most common form of the asbestos cancer, often start out like other respiratory diseases such as the flu, pneumonia, or COPD. However, anyone with a history of asbestos exposure should seek medical attention immediately if he or she exhibits these symptoms generally for any of the mesothelioma:
- Bowel Obstruction
- Abdominal swelling and pain
- Lumps under the skin of the chest or abdomen
- Shortness of breath
- Chest pain
- Pleural effusion (fluid on the lungs)
- Weight loss
- Persistent cough
- Loss of appetite
How is Mesothelioma Diagnosed?
After seeing a physician, the diagnostic process determines the causes of these symptoms and a treatment plan. Mesothelioma Diagnostic Procedures
- Imaging tests are used to locate tumors inside the body. Tests like X-rays, CT scans, PET scans and MRIs are commonly used to diagnose mesothelioma.
- Blood-Marker Tests:
Doctors use a variety of blood tests in order to determine if cancer is present in patients. Doctors can also analyze the type of cancer and what treatment options work best for each patient.
A biopsy is a tissue or fluid sample taken from a tumor or its surrounding area. These samples are examined under a microscope to determine cell type and are the only way to definitively diagnose mesothelioma. Surgical biopsies are used to extract tissue from a patient. This sample of tissue is sent to a pathologist to examine for the presence of mesothelioma. This can be accomplished with traditional surgical methods or camera-assisted surgery. The various biopsy procedures are:
- Thoracotomy – This is a traditional biopsy of the chest cavity, which is useful for pleural mesothelioma diagnosis.
- Laparotomy – This is a traditional biopsy of the abdominal cavity, which is useful for peritoneal mesothelioma diagnosis (peritoneum covers the abdominal organs)
- Thoracoscopy – A thoracoscopy is an alternative, less invasive chest biopsy for pleural mesothelioma diagnosis taken with the help of a camera.
- Laparoscopy – A laparoscopy is an alternative, less invasive abdominal biopsy for peritoneal mesothelioma diagnosis.
- Mediastinoscopy – A mediastinoscopy is an alternative, less invasive chest biopsy.