Stage I of the TNM mesothelioma staging involves the pleura on one side of the chest cavity only. The chest pleura are the cellular membranes (the mesothelium) located between the inside of the thoracic cavity (chest wall) and the lungs themselves. Stage I of the TNM mesothelioma staging involves the pleura on one side of the chest cavity only.
The chest pleura are the cellular membranes (the mesothelium) located between the inside of the thoracic cavity (chest wall) and the lungs themselves.
The mesothelium produces a fluid that lubricates and protects the lungs. In cases of mesothelioma, the DNA of the mesothelial cells is damaged by exposure to asbestos fibers, causing them to become malignant (cancerous) and grow uncontrollably; excess fluid and tumors are also produced within the pleura, spreading malignant cells into other tissues.
Mesothelioma involves the right or left pleura only. From the affected pleura, the malignancy may also have spread into the lung, pericardium (lining of the protective sac that surrounds the heart) or diaphragm (muscle that separates chest cavity from abdominal cavity) on the same side. Lymph nodes on both sides remain unaffected.
These limitations define TNM mesothelioma Stage I.
