Mediastinal and carcinoid lung cancers occur infrequently.
Carcinoid tumors are rare cancers that most often appear in the stomach or intestines. However, they do sometimes start in the lung. About 1 to 2 percent of all lung cancers are carcinoid cancers. There are two types of carcinoid tumors, typical and atypical.
- Typical carcinoids grow slowly and don’t often spread beyond the lungs. Nine out of 10 lung carcinoids are typical carcinoids.
- Atypical carcinoids grow faster and are slightly more likely to spread outside the lungs.
Carcinoid tumors are also sometimes categorized by where they start in the lung:
- Central carcinoids form in the bronchi, which are the large airways located near the center of the lungs. Most lung carcinoid tumors start there. These carcinoids are almost always typical carcinoids.
- Peripheral carcinoids develop in the smaller airways on the edges of the lungs and they too are almost always typical carcinoids.
Lung carcinoid tumors are most often treated by surgery . Chemotherapy and radiation therapy may be used as adjunct therapies or if surgery is not possible.
Mediastinal tumors are rare tumors that develop in the mediastinum, the area of the chest that separates the lungs. It is surrounded by the breastbone in front and spine in the back.
They can be benign or cancerous, forming from any tissue that exists or passes through the chest cavity. Most mediastinal tumors in children are benign while many mediastinal tumors in adults are cancerous. Because they are located in the chest cavity where the heart and major arteries are or near the spinal cord in back, both benign and malignant tumors must be treated.
There are several types of mediastinal tumors:
Germ cell tumors: These cancers are very treatable and often curable. They develop from reproductive cells and are more often found in the reproductive system for both men and women. When found outside the reproductive system, they may also be called extragonadal germ cell tumors (EGGCT). How these cells move from the reproductive system to the mediastinum is not currently known.
Lymphomas: These malignant tumors start in the lymphatic system and include Hodgkin’s lymphoma and non-Hodgkin’s lymphoma. The lymphatic system is a complex network of capillaries, thin vessels, valves, ducts, nodes, and organs that helps to protect and maintain the fluid environment of the body by filtering and draining lymph. In rare case, lymphoma can originate in the lungs.
Teratomas: These malignant tumors are made of cysts that contain one or more layers of embryonic cells. The layers are called ectoderms, medosderms, and endoderms. A rare cancer, teratomas occur most often in young men in their 20s and 30s. The tumors are most often located in the chest area. By the time the cancer is diagnosed, they have often spread. A number of other cancers are often associated with these tumors, including:
- Acute myelogenous leukemia (AML)
- Embryonal rhabdomyosarcoma
- Malignant histiocytosis
- Myelodysplasia (MDS)
- Small cell undifferentiated carcinoma
Thymomas: Thymomas and thymic carcinoma are rare cancers in which cancerous cells form on the outside of the thymus, a small organ that makes white blood cells and is located in the upper chest. Thymomas are rarely malignant, grow slowly and don’t often spread beyond the thymus. Thymoma is linked with myasthenia gravis and other autoimmune diseases (diseases that cause the immune system to attack healthy cells and tissue).
Thymic carcinomas grow more quickly and have usually spread by the time the cancer is diagnosed. People with thymoma often have autoimmune diseases as well.
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