Pancreatic Endocrine Tumors
Pancreatic endocrine tumors, more commonly known as neuroendocrine tumors, are neoplasm that occur in the islet cells of the pancreas. They spring from immature stem cells in the neuroendocrine system. This system is responsible for secreting hormones that regulate functions such as digestion and blood sugar levels. These islet cell tumors are very rare; only 1 person in 100,000 people develops them. They are most often found in women between 40 and 50 years of age. This differs from adenocarcinomas, a more common type of pancreatic tumor, which occurs largely in males over the age of 60.
There are two types of pancreatic endocrine tumors that exist: functioning and nonfunctioning. About seventy percent of cases are functioning, which means they secrete hormones. In fact, they are usually found only because of their hormones' over-secretion. Excess amounts of the hormones produce symptoms depending on what their purpose is. For example, glucaconomas produce mild diabetes due to their glucagons secretion. Glucagon's role is to increase blood sugar levels.
There are many types of pancreatic endocrine tumors. These types are composed of Insulinomas, Gastrinomas, VIPomas, Somatostatinomas, GNRHomas, Glucagonomas, ACTHomas, and PPomas. They are named for the hormones they secrete. The most common of these is the insulinoma. Unlike other species of pancreatic endocrine tumors, insulinomas are usually not cancerous. Compared with the 50 to 90 percent cancer rate in the others, only about 10 percent of insulinomas are malignant. Also, they almost always occur in the pancreas (more than 99 percent). They are slow growing and under an inch in size.
Insulinomas look much like other functional pancreatic tumors. They are pale pink throughout and often have a granular texture. They contain speckled coloring. And when pathologists study them with an electron microscope, they find the granules that secrete the hormones. This kind of pancreatic endocrine tumor is usually found by its symptoms, which occur from its production of insulin. This hormone controls how much glucose (sugar) is circulating in the blood at any given time. Insulin normally regulates blood sugar very effectively. Beta cells in the pancreas create it in response to high levels of blood glucose. In the presence of insulin, many cell types, such as muscle, red blood cells, and fat cells, absorb the sugar. Because of their absorption, the amount of sugar in the blood falls. When the blood sugar levels have been brought into a normal range, the lowered levels signal the beta cells to slow their secretion. With lower levels of insulin, cells absorb less sugar. Beta cells never totally cease secretion, but they do drastically limit their output. But this changes when an insulinoma exists. It does not respond to the signal to slow. Thus, a condition called hypoglycemia results. This refers to a low level of glucose in the blood. Because of the increased sugar absorption, people with this kind of pancreatic endocrine tumor are overweight. Hypoglycemia also results in other symptoms: altered states of consciousness confusion, visual disturbances such as hallucinations, weakness, tremors, sweats, and even seizures. After the pancreatic endocrine tumors are diagnosed, usually with imaging technology and chemical tests, doctors attempt to control the tumors' hormone production. Then they remove the neoplasm via surgery. If the tumor was cancerous, chemotherapy and radiation is also used. The survival rate of those with cancerous pancreatic endocrine tumors is about 5 years. Of course, when the growth is benign, this does not apply. In these cases, pancreatic endocrine tumors usually do not return, and the person continues with his or her life.
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