Endocrine Pancreatic Tumors
Endocrine pancreatic tumors, also called neuroendocrine tumors, occur in the islet cells of the pancreas. Immature stem cells in the neuroendocrine system give rise to these tumors. The neuroendocrine system secretes hormones that control functions like digestion and blood sugar levels. The incidence of endocrine pancreatic tumors is quite low, with only 1 person in every 100,000 developing them. They differ from their cousins the adenocarcinomas in that they are rare, they occur more in women between the age of 40 and 50 years, they cause cancer at a lower rate, and about seventy percent of them secrete hormones. The population that creates hormones is called functional. These functional tumors fall into one of the following types: Insulinomas, Gastrinomas, VIPomas, Somatostatinomas, GNRHomas, Glucagonomas, ACTHomas, or PPomas. The last three occur exclusively on the pancreas.
The first type, the glucagonoma, are rare, occurring in the alpha cells of the pancreas. They appear in people between the ages of 50 and 70. They usually are less than 5 centimeters long, and 50 to 80 percent are cancerous. When they metastasize, they first affect the liver and surrounding lymph nodes.
Glucagonomas secrete the hormone glucagons, hence their name. The alpha cells in the pancreas create glucagon. Glucagon serves as insulin's antagonist, raising blood sugar levels. When blood glucose levels rise, the alpha cells respond with a higher secretion of glucagon. The hormone affects many cells, just as does insulin, but it mainly affects the liver. It reacts by releasing more glucose. But when blood glucose rises, the amount of glucose the alpha cells secrete falls. Glucagonomas, however, do not lower their glucagon production. With higher levels of the hormone comes hyperglycemia, which is a high blood sugar. As a result, symptoms such as rashes (necrolytic erythema migrans), mental disturbances, venous thrombosis, and anemia result. Mild glucose intolerance occurs first in 90 percent of cases.
The second type of endocrine pancreatic tumors only found in the pancreas is the ACTHoma. Over 95 percent of ACTHomas are cancerous. The "ACTH" stands for adrenocorticotropic hormone, which the tumor secretes. The hormone stimulates the adrenal cortex to produce cortisol. A corticosteroid hormone, cortisol is created in response to stress. Its function is to increase blood pressure and blood sugar, and suppress the immune system. ACTHomas create symptoms like those found in Cushing's syndrome. This includes rounded facial features and torso obesity; bruise-colored stretch marks over the buttocks, thighs, arms, and breasts; osteoporosis; high blood pressure; weakness; and hirsutism (facial hair growth in females). Also, skin may become fragile, thin, easily bruised, and slow to heal. The third endocrine pancreatic tumor type is the PPoma. The tumors have a wide range, affecting people from 20 to 70+ years, though the average is 51. Sixty percent of PPomas are cancerous. The neoplasm is named for is secretion of pancreatic polypeptide (PP). PP is a mysterious hormone whose blood levels increase with age, fasting, chronic renal failure, exercise, and pancreatic problems. Glucoganomas, ACTHomas, and PPomas are dangerous, if rare, tumors that should not be neglected. If you suspect you may have signs of these endocrine pancreatic tumors, see you doctor immediately. Prompt diagnosis and treatment are essential.
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