This is usually the non-cancerous tumor that develops in the pancreas and produces the excess insulin. The pancreas normally produces the insulin to regulate the blood sugar level in the body after consuming food. Normally, as the glucose level falls toward the normal limit, the insulin production also ceases allowing the glucose in the blood to remain in the normal range. The growth of the tumor in the pancreas causes abnormal regulation of the insulin and the tumor produces the extra insulin even when the glucose level becomes very low. This is normally a rare form of tumor estimated to affect around 3-4 million people.
Causes
In most of the cases, the cause remains unknown. In around 10% of the cases, it can develop as a part of another condition such as multiple endocrine neoplasia type 1 (MEN1) syndrome. Women appear to be more affected with this condition than the men and can develop between the ages of 40 and 60. Other genetic diseases that also increase the risk of developing this condition include von hippel-lindau syndrome and neurofibromatosis type 1.
Symptoms
One of the common symptoms associated with this condition is the abnormal insulin levels in the body which causes the sudden changes in the blood sugar levels. Some of the symptoms associated with low blood sugar levels include fatigue, sweating, lightheaded, palpitations, hunger, blurred vision, confusion, weakness and feeling sick. If individuals with the low blood sugar do not eat, they can become unconscious. In some of the cases, the tumors may be non-functional meaning they do not produce the extra insulin which doesn’t initially cause any symptoms. When the tumor is large enough, it may press on other organs or spread to other parts of the body causing its associated symptoms which may include jaundice, abdominal pain and diarrhea.
Diagnosis
The diagnosis of insulinoma on average is around 3 years from the start of the symptoms. If an individual is suspected of insulinoma, they may be hospitalized for a few days to monitor their blood sugar level and the presence of other materials in the blood with fasting. Individuals with this condition usually have very low blood sugar within a couple of days of starting this process. The transabdominal ultrasound imaging test may also be needed to determine the size and the location of the tumor. Additional tests include endoscopic ultrasound, MRI and CT scan. In the case the tumor is too small to be observed with the imaging system, a blood sample from various parts of the pancreas may be necessary to determine the location of the tumor that is producing the extra insulin.
Treatment
Surgery is the common treatment of insulinoma which can cure the condition. If the tumor cannot be surgically removed or if it has spread to the other parts of the body, then the medications are used to control the blood sugar levels and to provide relief from the symptoms.
References
http://www.cancerresearchuk.org/about-cancer/cancers-in-general/cancer-questions/insulinomas#causes
https://medlineplus.gov/ency/article/000387.htm
http://endocrinediseases.org/neuroendocrine/insulinoma.shtml
