Mesothelioma is a debilitating form of cancer which, although rare, has a relatively high occurrence in certain occupations, particular those involving asbestos, such as milling, shipbuilding, metalworking, plumbing or pipefitting and construction. This cancer has a high rate of malignancy, and attacks the mesothelium, a cellular membrane which covers most organs in the body, including the heart and lungs.
When airborne asbestos fibers are inhaled, they can penetrate the mesothelium—usually that which surrounds the lungs—and lead to the formation of tumors. However, inhaled asbestos can also affect the mesothelium surrounding other organs, including the heart, stomach and testes. The four types of mesothelioma, from most to least common, are pleural, peritoneal, pericardial, and testicular.
Mesothelioma may present with a variety of symptoms, but may not be diagnosed until relatively late in life since symptoms may take 30 to 50 years to become prevalent. This time between asbestos exposure and diagnosis of the disease is known as a “latency period,” and is one of the reasons that most cases of mesothelioma are not discovered until they have reached Stage III or Stage IV.
In the most common form of this cancer, pleural mesothelioma, symptoms frequently include a dry or rasping cough which does not go away, chest pains, and shortness of breath or difficulty breathing. Excessive fatigue, initially after exertion but later during periods of rest, may also occur. Some patients may also experience difficulty swallowing, weight loss, hoarseness and swelling of the face or arms.
A persistent cough and pain in the chest can be due to pleural effusion, which is fluid buildup in the pleural space. Over time these initial symptoms can lead to fatigue or anemia, as well as hemoptysis, which is coughing up blood in the sputum. If pleural mesothelioma continues without treatment, it can even lead to outcomes as severe as the collapse of a lung, or pneumothorax - a dangerous medical emergency in which air or gas gets into the pleural cavity after leaking out of the lungs. However, part of the difficulty of diagnosing mesothelioma is that these symptoms can be present in a variety of other respiratory ailments. Often, patients either delay seeking medical attention for their symptoms, because they believe they are simply suffering from a simple virus or respiratory infection, or they do consult with their doctor and are misdiagnosed with bronchitis, asthma or emphysema. For this reason, it's essential that anyone with possible exposure to asbestos, whether occupational or secondhand, let their doctor know about this so that mesothelioma can be considered should the patient present with these symptoms.
Diagnostic tests such as biopsy, x-ray, CT scan or MRI, or analysis of fluid in the lungs or pleural cavity, will generally be performed in order to successfully diagnose pleural mesothelioma.
The peritoneum, which is the mesothelial membrane covering the organs such as the liver, kidneys, and intestines, is also susceptible to mesothelioma, and carries its own unique set of symptoms. Peritoneal mesothelioma often firsts manifests as cachexia, or a loss of appetite, as well as loss of weight, anemia, and fatigue, due to damage done to the intestines and stomach. Additionally, there will also be abdominal pain and ascites, which is a build-up of fluid between the peritoneum and the internal organs. Ascites can also lead to abdominal swelling, which will appear paradoxical given the patient's lack of appetite and overall weight loss. Due to the diversity of organs affected by this type of cancer, there mayl also be symptoms ranging from fever to bowel obstruction and abnormalities with blood clotting. Generally these symptoms appear even later in life than those of pleural mesothelioma.
Pericardial mesothelioma, or a cancer attacking the membrane around the heart, is more rare, but no less deadly than the other forms of this disease. Many of the symptoms of pericardial mesothelioma are caused by the build-up of fluid in the pericardial space between the heart and mesothelium. These symptoms can include heart palpitations, heart murmurs, and arrhythmia, also known as an irregular heartbeat. Chest pain, dyspnea (difficulty breathing, even while lying down or resting), or a lingering cough may also be present, similar to the same symptoms seen in pleural mesothelioma. These symptoms can in turn lead to chronic fatigue, as well as fevers and inappropriate sweating, especially at night. As with pleural mesothelioma, many of these symptoms are so similar to those of other heart disorders that a successful diagnosis can often be quite difficult, and may even require an MRI or biopsy.
The rarest type of mesothelioma is testicular mesothelioma, which affects the tunica vaginalis, the membrane surrounding the testicles. This type of mesothelioma is so rare that there is no official diagnostic set of symptoms for the disease. However, in those cases which have been studied and treated, the main symptoms are usually testicular lumps and swelling in the scrotum area, which can lead to pain or tenderness. Since this form of mesothelioma is usually not diagnosed until the lumps appear, most cases of testicular mesothelioma without lumps were only diagnosed after a biopsy was performed for other diseases which can affect the testicles.
As mesothelioma develops, it may metastasize, which is a process in which cancer cells become separated from the original tumor and travel through the bloodstream to other areas of the body. If this happens, the most common symptoms can be swelling and pain in the neck and face, as well as difficulty swallowing. Symptoms of pleural and peritoneal mesothelioma may be present at the same time, for example, having abdominal pain and swelling, but also pleural effusion, or fluid buildup in the pleural cavity.
Other signs of advanced forms of mesothelioma can include low blood sugar as the body is unable to process food properly; pulmonary emboli, which are blood clots in the lungs; and blood inappropriately clotting in the veins, which can lead to thrombophlebitis, a condition where the vein begins to swell, leading to pain and inflammation in the affected area and the extremities. The most serious consequence of abnormal blood clotting may be disseminated intravascular coagulation, which refers to widespread small blood clots throughout the body. This can cause bleeding from the skin, respiratory tract and digestive tract, and has the potential to cause multiple organ failure.
If the person is unable to clear the compound bilirubin through the kidneys and liver due to mesothelioma, a patient can develop jaundice, which is a buildup of bilirubin and which leads to yellow coloration of the skin and the whites of the eyes. However, it is important to note that while a metastasized cancer can spread to nearly any part of the body and a large array of symptoms could be present in this event, mesothelioma does not generally spread to the brain, bones, or adrenal glands.