When the majority of pleural mesotheliomas are diagnosed, they are made up of many small nodules along the pleural surface. These nodules are about one millimeter to one centimeter in size. In most cases, this nodule covering is associated with a pleural effusion, which is a buildup of pleural fluid.
What Happens during the Later Stages of Pleural Mesothelioma?
As the disease progresses, the nodules merge together to create solid tumors that surround the lung and wipe out the pleural cavity. Mesothelioma penetrates the skeletal muscle in the chest wall and can also invade the skin, the tissue below the skin and the main functioning area of the lung. The tumor rind that surrounds the lung varies in thickness.
The portion of the tumor at the base of the pleural cavity is much thicker than the tumor portion that is at the top. Many times mesothelioma has a nodular shape and a thin tumor rind, making it resemble other types of lung cancer. Sometimes mesothelioma will spread to the lymph nodes in the triangular area in the center of the lung where the arteries, veins and nerves and bronchial airways enter the lungs. When this occurs, it produces a mass that is easier to recognize on a chest x-ray that the thin tumor rind.
Mesothelioma can invade the sac surrounding the heart and it can also affect the muscular tissue of the heart. It is common for pleural mesothelioma to penetrate through the side of the diaphragm near the diseased lung and extend into the abdominal cavity.
What does Peritoneal Mesothelioma Look Like?
Just like pleural mesothelioma, peritoneal mesothelioma starts as a series of small nodules that merge together over time to form a rind of tumor that encases organs inside the abdominal cavity. The rind can be so large that it compresses the organs so tightly that they are non-existent. Peritoneal mesothelioma is also associated with a fluid buildup.
How does a Mesothelioma Tumor in the Tunica Vaginalis Begin?
Mesothelioma of the tunica vaginalis, or the lining of the testes, starts as a mass in that area. It can remain localized; however, it is very common for this type of tumor to invade the abdominal cavity.
How does Pericardial Mesothelioma Present?
Primary pericardial mesothelioma tumors, meaning tumors that original in the sac surrounding the heart are very rare. The chief concern when diagnosing this type of tumor is determining that it is really a primary tumor and not just an extension of pleural mesothelioma. Pericardial mesothelioma is similar to both pleural and pericardial in that it begins as a large amount of small nodules that merge together over time to form a tumor rind around the heart that wipes out the sac that usually surrounds it.
Is Metastasis Common in Mesothelioma?
Metastases are common in mesothelioma, but not as common as in other types of lung cancer. The disease typically metastasizes to the:
- Lymph nodes in the triangular section in the center of the lung
- Lymph nodes that collect the lymph that drains out of the lungs
- Pleural surface of the lung that is not covered by the tumor
Mesothelioma can metastasize to almost any organ. There have been about 25 cases of the disease metastasizing to the brain.