Causative & risk factors
Carcinoid tumors arise from neuro-endocrine cells present in the lungs and the gastro-intestinal tract. As with most cancers, the exact cause of the onset of carcinoid tumors is not known. However it is known that a family history of multiple endocrine neoplasia type I (MEN I) is associated with an increased risk of developing carcinoid tumors.
Clinical presentation
The symptoms of this condition are largely determined by the location of the carcinoid tumors and the chemicals they secrete. The symptoms produced by carcinoid tumors are referred to as carcinoid syndrome.
Flushing of the face (pink, red or purple) is a common feature and may be triggered by stress or exercise.
Patients with abdominal carcinoid tumors usually suffer from cramps in the abdomen accompanied by diarrhea. There may be pain or bleeding from the rectum. Sometimes intestinal obstruction may occur presenting with an inability to pass stool, nausea and vomiting.
Lung carcinoids are characterized by chest pain, breathlessness, wheezing, palpitations and tachycardia. There may be weight gain around the midriff and the upper portion of the back. Discolored (purplish) marks may appear on the skin.
Investigations
Since carcinoid syndrome produces non-specific, variable symptoms, the diagnosis can be easily missed.
Blood tests are performed to check chromogranin A. Urine testing is done to detect a substance called 5-HIAA.
Imaging tests such as X-rays, CT scans or MRI scans are used to look for carcinoid tumors. A specialized imaging test known as an octreoscan is performed after injecting the patient’s vein with a radioactive material and a specific substance.
Endoscopy with or without a biopsy examination is performed in areas that are suspected of having carcinoid tumors.
Treatment
The primary treatment is surgical removal of the carcinoid tumors. When this is not possible, octreotide and other drugs are used to control the symptoms. Radiofrequency ablation therapy and cryotherapy are other treatment options. Chemotherapy works well for certain carcinoid tumors, especially the ones located in the pancreas.
Since carcinoids are usually slow-growing tumors, a patient with carcinoid syndrome has a fairly good prognosis.
