Glucagon is a hormone normally secreted by the pancreas when blood glucose levels fall. Glucagon simulates the liver to break down stored carbohydrates to increase blood glucose. Glucagonomas are a type of pancreatic endocrine tumor Overview of Pancreatic Endocrine Tumors The pancreas is an organ located in the upper part of the abdomen. It produces digestive juices that are secreted into the digestive tract. The pancreas also produces insulin, which helps control... read more . About 80% of glucagonomas are cancerous (malignant). However, they grow slowly, and many people survive for 15 years or more after the diagnosis. The average age at which symptoms begin is 50. About 80% of people with glucagonomas are women. A few people have multiple endocrine neoplasia Multiple Endocrine Neoplasia Syndromes (MEN) Multiple endocrine neoplasia syndromes are rare, inherited disorders in which several endocrine glands develop noncancerous (benign) or cancerous (malignant) tumors or grow excessively without... read more .
High levels of glucagon in the blood cause the same symptoms as diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , such as weight loss and frequent, excessive urination. In addition, 90% of people have the very distinctive features of a chronic brownish red rash (called necrolytic migratory erythema) and a smooth, shiny, bright red-orange tongue. The mouth also may have cracks at the corners. The rash, which causes scaling, starts in the groin and moves to the buttocks, forearms, hands, feet, and legs.
The diagnosis of glucagonoma is made by identifying high levels of glucagon in the blood. Doctors then locate the tumor by doing computed tomography Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT—see also Computed Tomography (CT)) and magnetic resonance imaging (MRI—see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location... read more (CT) of the abdomen followed by endoscopic ultrasonography Ultrasound Scanning (Ultrasonography) of the Abdomen Ultrasound scanning uses sound waves to produce pictures of internal organs (see also Ultrasonography). An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas... read more . Magnetic resonance imaging Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT—see also Computed Tomography (CT)) and magnetic resonance imaging (MRI—see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location... read more (MRI) or positron emission tomography Positron Emission Tomography (PET) Positron emission tomography (PET) is a type of radionuclide scanning. A radionuclide is a radioactive form of an element, which means it is an unstable atom that becomes more stable by releasing... read more (PET) may be used if the CT scan does not show a tumor.
Ideally, the tumor is surgically removed, which eliminates all symptoms. However, if removal is not possible or if the tumor has spread, chemotherapy may reduce the levels of glucagon and lessen the symptoms. However, chemotherapy does not improve survival.
The drug octreotide can be used to reduce glucagon levels, may clear up the rash, and may restore appetite, facilitating weight gain. But octreotide may elevate the levels of glucose in the blood even more.
Zinc taken by mouth, applied in an ointment, or given by vein (intravenously) may be used to treat the rash. Sometimes the rash is treated with intravenous amino acids or fatty acids.