Carcinoid lung tumour is a rare type of lung tumour, which develops from a special type of cell present in the lungs called neuroendocrine cell/s.
Tumours are usually classified as benign (noncancerous) or malignant (cancerous) based on how they behave clinically; but a few types of tumours are neither benign (noncancerous) nor malignant (cancerous). These tumours behave between the two classifications of benign and malignant and therefore, they are sometimes called "midway" tumours. Carcinoid tumours behave neither like benign (noncancerous) nor like malignant (cancerous) tumours and are considered as "midway" tumours. Often they are referred to as "cancers in slow motion." They can become malignant, but in most cases they grow so slowly that people with carcinoid tumours usually live for many years (may also be a normal lifespan).
The neuroendocrine cells, from which the carcinoid tumours develop, have some properties of both nerve cells and cells of endocrine (hormone-producing) glands. These cells are present throughout different organs of the body such as lungs, stomach and intestines. If these cells lose their controlled and organized division and growth, they can form (tumours) in many different organs, but most of these tumours occur in the endocrine glands such as the adrenal or thyroid glands or the intestinal tract. Carcinoid tumours can also develop in the lungs. Carcinoid lung tumours form only about 10% of all carcinoid tumours and about 1%-2% of all lung tumours. Carcinoid lung tumours can be categorized as:
Typical carcinoid lung tumours: These occur more commonly than atypical carcinoid lung tumours. They usually grow slowly and rarely spread to other parts of the body beyond the lungs.
Atypical carcinoid lung tumours: These tumours grow more aggressively as compared with typical carcinoid lung tumours and are more likely to spread to other parts of the body beyond the lungs. The atypical carcinoid lung tumour forms about 10% of all carcinoid lung tumours.
Some carcinoid tumours may secrete hormone-like substances, which cause specific symptoms. The term carcinoid syndrome is used to refer to the symptoms, which are caused due to the hormone-like substances produced by the carcinoid tumours. In carcinoid tumours, the symptoms occur as result of excessive response of the body to the hormone-like substances produced. Carcinoid syndrome, however, occurs rarely in people with carcinoid lung tumours (in about 2% of people). Most cases with carcinoid tumours are treated surgically whereby the tumour is removed. If the tumour is localized to lungs, surgery can cure the cancer.