Mesothelioma is a very rare cancer which originates in the membranes lining the chest, abdominal cavities or the heart. These membranes are called mesothelium, which is a protective sac of thin tissues covering vital organs. The mesothelium is comprised of two layers, the visceral membrane which covers the organ and the parietal membrane which forms a sac around it. A fluid is produced by the mesothelium to allow organs to move easily in the body.

Prevalence Of Mesothelioma And Its Associated Risk Factors

Although relatively rare, the incidence of mesothelioma has increased over the last 20 years with roughly 2,000 new cases reported in the U.S. each year. The disease is more common in men with a male- to-female ratio of 3:1. Occupational exposure to asbestos is reported in 3-4 out of every 5 cases. Those who work with asbestos carry an overall 8% lifetime risk of developing malignant pleural mesothelioma. Increase in both time and intensity of exposure increases the risk for all asbestos-related disease. Even those indirectly exposed, such as family members of asbestos workers, have an increased risk of mesothelioma. Cigarette smoking does not increase the incidence of mesothelioma. However, it should be noted that a combined history of asbestos exposure and smoking increases the risk of bronchogenic cancer. Additionally, not all cases of mesothelioma have an identified exposure to asbestos and not all who are exposed to asbestos will develop asbestos-related disease.

Mesothelioma occurs when the cells in the tissue continually produce this fluid. Excess fluid and tissue builds up around these vital organs making it difficult for them to function effectively. The cells can then multiply and spread to other organs or areas in the body which is called metastasis.

The majority of malignant mesotheliomas (around 90%) occur in the lining of the lungs. The remaining cases of mesotheliomas develop in the abdomen and the heart.

This is a free informational resource for mesothelioma patients and their families, answering common questions related to mesothelioma and related diseases.

Causes And Symptoms Of Mesothelioma

Mesothelioma is caused by prolonged exposure to asbestos. Most cases occur in those working in direct contact, but it can be acquired indirectly by the asbestos that workers bring into their homes or by living near a manufacturer. What are some mesothelioma symptoms?

Pleural: The most common symptom, pleural effusion, occurs when mesothelial cells in the visceral and parietal pleura overproduce fluid. This may lead to shortness of breath, pain/difficulty breathing and a persistent cough. Less often, fever, weight-loss and/or night sweats, pain in the back or the lower chest, dyspnea, and dry cough. Patients may have no symptoms or just a feeling of malaise or being unwell.

Peritoneal: Accumulated peritoneal fluid causes abdominal swelling, pain with nausea and weight-loss, and possibly a palpable mass. Less commonly is anemia, pedal edema, bowel obstruction and/or abnormal clotting.

Pericardial: Symptoms can be very similar to pleural mesothelioma and other maladies of the heart and/or lungs, but may also include exertion-induced chest pain, palpitations, and face and upper- extremity swelling.

Symptoms Of Mesothelioma In Depth

Patients with mesothelioma generally present with chest pain that is quite severe and sometimes disabling. The nature of this pain is generally described as aching and non-pleuritic in character. Patients generally also have shortness of breath. This shortness of breath may or may not be accompanied by a cough. Symptoms that are less often seen include night sweats, fever, and weight loss. If the tumor has progressed into the peritoneal cavity, patient may experience abdominal pain or swelling. Peritoneal mesothelioma may also present with nausea, bowel obstruction, anemia, or pedal edema. Some patients present with no mesothelioma symptoms at all. Signs on physical exam may reveal chest dullness to percussion secondary to pleural effusion. Plain radiographs will also reveal pleural effusions. Mesothelioma and its subsequent pleural effusion are most often right-sided. Mesothelioma Questions

Some Symptoms Of Mesothelioma Mimic Other Ailments

Many symptoms of malignant mesothelioma are similar to those of other health problems. Chest pain, shortness of breath, persistent cough, difficulty swallowing, and weight loss are symptomatic of pleural mesothelioma. Abdominal pain and swelling, nausea, and weight loss are associated with peritoneal mesothelioma. Peritoneal mesothelioma is also sometimes accompanied by bowel obstruction, anemia, abnormal blood clotting, and fever. A more characteristic symptom of mesothelioma is fluid accumulation in the cavity lined by the mesothelia. In early stages of mesothelioma, tumors are localized to the mesothelial membrane of origin. In malignant pleural mesothelioma, tumors may also develop in the lungs, pericardium, or diaphragm. Advanced pleural mesothelioma is associated with the progressive spread of cancerous cells to the chest wall, esophagus, heart, lymph nodes, and peritoneum.

The Early Symptoms Of Pleural Mesothelioma

The first symptoms of pleural mesothelioma are generalized and usually go unrecognized for quite sometime. Symptoms such as shortness of breath, persistent cough, and chest tightness/pain are common but, some patients are asymptomatic. These symptoms are usually caused by a pleural effusion. Pleural effusion is when fluid settles between the parietal and visceral pleura in the lungs. This happens due to the damage, by the cancer, to the mesothelial cells that make up the parietal and visceral pleura. The pleura, under healthy circumstances, should absorb any extra fluid formed in the pleural cavity, when cancer is present, normal fluid is not reabsorbed. There are two types of pleural effusions, transudates and exudates. The type of pleural effusion that presents in mesothelioma is exudative. As the pleural cavity continues to fill with fluid, patients present most commonly with shortness of breath, which then leads to a more thorough exam and more extensive testing.

Signs and Symptoms Of Malignant Mesothelioma: Some Startling Facts & Figures

Initial symptoms of mesothelioma are vague, and often ignored or mistaken for a different disease process. It is for this reason that a complete physical and medical history must be obtained by the doctor. Some patients may not show any symptoms until the asbestos cancer has reached an advanced stage.

The early symptoms of mesothelioma resemble common, minor illnesses. Mesothelioma symptoms generally appear 2 to 3 months before a diagnosis is made. In about 25% of cases, symptoms may have appeared for six months before a diagnosis is made.

In 50% of patients, pleural mesothelioma presents with hyperesthesia in the low back and at the side of the thorax. The hyperesthesia may be accompanied with difficult respiration. Patients may also report difficulty while swallowing, coughing, elevated temperature, tiredness and loss of weight.

Peritoneal mesothelioma presents with abdominal hyperesthesia, vomiting, nausea and loss of weight.

If a patient exhibits the symptoms of mesothelioma, and also has the risk factors, imaging test will be performed to determine the diagnosis.

An x-ray is generally the first test performed as it will show an irregularity which would suggest the presence of a mesothelioma. If a mesothelioma is suspected, either a computed tomography (CT) scan, or a magnetic resonance imaging (MRI) scan will be performed to establish the size, extent, and location of the mesothelioma.

How To Distinguish Between The Symptoms Of Pleural And Peritoneal Mesothelioma

Pleural mesothelioma can cause these symptoms:

  • Chest wall pain, may be in the side or lower back
  • Pleural effusion
  • Dyspnea
  • Wheezing, and/or persistent cough
  • Husky voice, hoarseness
  • Difficulty swallowing
  • Fever
  • In severe cases, the person may have many tumor masses. The individual may develop a pneumothorax, or collapse of the lung.
  • Pleural tumors are usually found on only one side of the lung.

Peritoneal mesothelioma can cause these symptoms:

  • Cachexia, (physical wasting with loss of weight and muscle mass caused by disease)
  • Abdominal pain and swelling due to ascites (may be severe)
  • Abdominal mass
  • Bowel dysfunction
  • Thrombophlebitis
  • Disseminated intravascular coagulation
  • Jaundice
  • Hypoglycemia
  • Pleural effusion
  • Pulmonary emboli

Treatment Of Mesothelioma

Treatment can consist of radiation, surgery, or chemotherapy but results have been disappointing. Clinical trials are underway to study other ways to fight this cancer and interested patients should consult with their doctor about participation in such trials. For now, palliative care with narcotic pain relief and supplemental oxygen for shortness of breath is frequently all that can be done. Fluid build-up is drained via thoracentesis or paracentesis.

How Is Mesothelioma Diagnosed?

  • The lung exam may reveal dullness to percussion and diminished breath sounds.
  • Another physical exam finding may be finger clubbing which is also found in asbestosis.
  • Radiographic studies may aid in the diagnosis of mesothelioma.
  • Chest x-rays may reveal nodular, irregular, unilateral pleural thickening and unilateral pleural effusion.
  • CT scans are helpful in determining the extent of pleural involvement.
  • Abdominal CT may show sheet-like masses involving the omentum and mesentery.
  • Pleural fluid is usually exudative and may be hemorrhagic, but this is not diagnostic.
  • Open pleural biopsy is necessary for histologic diagnosis.
  • Histological types of mesothelioma are epithelial, sarcomatous, or mixed.
  • Special stains and electron microscopy may be needed to confirm the histologic diagnosis.
  • Diagnosis of mesothelioma is confirmed by thoracoscopy or pleuroscopy.

The Three Cancer Cell Types Associated With Malignant Mesothelioma

Malignant mesothelioma is divided into three types of cancer cells: epitheliod, sarcomatoid and biphasic.

Epitheliod cancer cells have a tubular pattern with a distinct cell nucleus, and tend t be uniform in shape. The individual cells resemble cubes.

Sarcamatoid cancer cells typically are oval and irregular in shape, and have a less distinct nucleum that do epitheliod cells. This is the least common type of mesothelioma cancer cell.

Biphasic cancer cells consist of a combination of both epitheliod and sarcomatoid cells. In some instances of biphasic cancer cells, both epitheliod and sarcomatoid cells are intermixed throughout a tumor. In other cases, the epitheliod and sarcomatoid cells are clustered into type-specific groupings, often with transitional areas in between

Can Mesothelioma Be Benign?


Technically there are two types of mesothelioma:

  1. Localized (benign or malignant)
  2. Diffuse (highly malignant)

Localized mesothelioma often presents with: pleuritic pain, joint pain and swelling, and dyspnea. Diffuse mesothelioma often presents with chest pain (not necessarily pleuritic), malaise, weight loss, and cough. Pleural effusion is the hallmark sign presenting in greater than 75% of diffuse cases, but on 10% to 15% of the time in local disease. Benign disease presents as "broccoli" or "cauliflower" pedunculated masses on the visceral pleura, as opposed to the "sheet like" growth of malignant disease. Overall malignant mesothelioma occurs in the pleura 90% of the time. Pleural malignant mesothelioma is associated with asbestos exposure in 77% of cases.

Last Updated: 07/29/2014