Mesothelioma Questions

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.

Pleural mesothelioma is not always cancer.  It can be localized and benign or  generalized and malignant.

When mesothelioma is localized and benign, it can be surgically removed and not generally life threatening.

Generalized and malignant mesothelioma, however, is an aggressive and dangerous cancer.  While treatment options are available, life expectancy for patients is limited.  Because of the aggressive nature of this form of cancer, treatment usually begins immediately upon diagnosis.  Treatment may include a combination of any or all of the following:  surgery, radiation, and chemotherapy.  Even in cases where the malignancy cannot be completely removed, surgery is sometimes performed to reduce the size of tumors as a means of improving the patient’s quality of life.  Additional treatment may involve draining fluid that builds up in the patient’s lungs.

Diagnosing mesothelioma involves both imaging tests and biopsies.  Imaging tests, which may include x-rays, CT scans, and/or MRI scans, are usually the first step in making a preliminary diagnosis.

If an imaging test indicates the possibility that mesothelioma may be present, the next step is to perform a biopsy.  Biopsies involve collection of tissue to be examined by a pathologist.  A needle biopsy involves extracting tissue via a hollow needle inserted into the chest cavity.  This is the least invasive, but also the least conclusive biopsy technique.  A surgical biopsy involves making an actual incision for the purpose of collecting tissue for examination.

The tissue is then examined by a pathologist, who checks for the presence of malignant cells is the sample.

The three forms of mesothelioma are pleural, peritoneal, and pericardial.

Pleural mesothelioma affects the lung cavity and the protective lining of the lungs.  Symptoms include shortness of breath, difficulty breathing or swallowing, persistent coughing and coughing up blood, shortness of breath, rasping, weight loss, and fever.

Peritoneal mesothelioma affects the stomach and abdomen initially; however it can spread to other parts of the body.  Symptoms include abdominal pain and swelling, nausea, appetite loss, vomiting, chest pain, breathing problems, obstructed bowels, fever, bleeding, and abnormal blood clotting.

Pericardial mesothelioma affects the heart and the surrounding cavity.  Symptoms include chest pain, heart palpitations, persistent coughing, shortness of breath, and general breathing trouble.

The 3 most common treatment options for mesothelioma are surgery, chemotherapy, and radiation therapy:
A pleurectomy/decortication is the surgical removal of a tumor or mass in or around the lung.  In some cases, all or part of the lung may have to be removed.
Cytoreductive surgery is the removal of all or nearly all of a tumor located in the peritoneal cavity.
If any residual cancer cells exist after surgery, a follow-up of Intra-Peritoneal Hyperthermic Chemotherapy (IPHC) can be delivered to the abdominal cavity.
Radiotherapy, if indicated, is usually the final stage of treatment.  A large dose of radiation is administered to the residual cancerous area to kill any remaining cancerous cells.

Gene Therapy is a less common approach to treating mesothelioma.  This involves injecting therapeutic genes into the tumor cells.  This is believed to promote tumor regression, (tumor shrinkage.)

The following are methods used to diagnose mesothelioma:
Chest X-ray – will show an abnormal fluid build-up within the pleural cavity, called a pleural effusion.  Another sign may include a mass or calcification near or in the pleural lining.
Computed Tomography (CT) Scan – will confirm a pleural effusion. It will also give the exact location and measurement of a mass or suspected tumor.  Another sign may include thickening of the pleural lining (usually greater than 1 cm.)
Computed Tomography & Positron Emission Tomography Scan (CT/PET) – combined exams that will show the extent of the malignant disease.  This is a test which evaluates the biological function of the malignancy to determine the “stage” of the disease.
Fine needle aspiration – a tissue or fluid sample is collected using a thin needle.  The sample is thin viewed under a microscope to determine whether it’s malignant (cancerous) or benign (non-cancerous).

The most common sites for mesothelioma are the pleura (lining of the lungs) and the peritoneum (lining of the abdomen.)

Symptoms of pleural mesothelioma can include: dyspnea (difficulty breathing), chest pain near or under the rib cage, fever, night sweats, persistent dry cough, weight loss, lethargy, and fatigue.

Symptoms of peritoneal mesothelioma can include: swelling, pain (due to increased fluid and pressure in the abdomen), weight loss, a mass or lump in the abdomen, bowel obstruction (blockage), irregular blood clotting, anemia (decreased red blood cell count), and fever.

Symptoms of pericardial mesothelioma can include: chest pain and shortness of breath .  This can be caused by a tumor or fluid build-up that may compress the heart during beats.

Symtoms of mesothelioma can manifest as many as 30 years from the initial time of exposure.

Asbestos is a naturally occurring mineral or group of minerals.  It is a “mined” mineral that takes on the form of natural fibers.  These fibers a capable of floating in air and can lodge into the lungs, causing infection and other damage to the cells.

Asbestos is also found in products such as old plastics, textiles, electrical switchboards, caulking/patching tape, brake linings, paper products, crayons containing talc, and heavy industrial sealants.  There is a widespread use of asbestos in manufacturing because heat and chemicals do not affect asbestos and it is not a conductor of electricity. Asbestos is often added to cement and plastic to increase its durability. It is also used in some products for fire proofing and sound absorption.

Asbestos is a dust-like fiber that clings to clothing, skin, fingernails, and hair.   As a result of this, workers exposed to asbestos also run the risk of exposing other people who are in close contact.

Certain organs such as the heart, the lungs, and the abdomen are surrounded by a thin tissue membrane.  The pericardium is the membrane that surrounds the heart, the pleura surrounds the lungs, and the peritoneum surrounds the abdomen.  These membranous layers are comprised of cells called mesothelium.

Cells within the body constantly divide and grow.  An irregular or abnormal growth or division of the cells creates a marked mass (tumor).  A tumor that develops in the mesothelium is called mesothelioma, or cancer of the mesothelium.

The most common type of mesothelioma is Malignant Pleural Mesothelioma (MPM).  The rarest form of mesothelioma is pericardial mesothelioma.  Mesothelioma is also referred celothelioma and/or asbestos cancer.  (It is important to note that Asbestosis is not the same as Mesothelioma.  Asbestosis is a non-malignant, chronic lung disease.)

Word Roots:
meso = middle or median
thelium  = layer of cellular tissue

Needle biopsy is one of two definitive ways to confirm a diagnosis of mesothelioma. The procedure is performed, using local anesthesia, to obtain tissue samples for pathologic examination. It is used instead of video assisted thoracoscopy when the patient has contraindications to, or cannot tolerate the general anesthesia needed for thoracoscopy.

In pleural needle biopsy, a large bore needle is inserted into the chest cavity in order to take sample tissue from the pleura, or lining of the lungs. Often, radiographic guidance, such as computerized tomography, assists in assuring proper placement of the needle. Tissue is aspirated into the needle, which is then removed. The tissue is sent to the pathology lab for microscopic examination. Needle biopsy has advantages in that it takes little time, and does not require general anesthesia, but it does not allow the surgeon to view the biopsy area, an advantage in video assisted thoracoscopy.