A glucagonoma is a pancreatic alpha-cell tumor that secretes glucagon, causing hyperglycemia and a characteristic rash. Diagnosis is by elevated glucagon levels and imaging studies. Tumor is localized with CT and endoscopic ultrasonography. Treatment is surgical resection.
(See also Overview of Pancreatic Endocrine Tumors.)
Glucagon is a hormone normally secreted by the pancreas when blood glucose levels fall. It stimulates glycogenolysis in the liver and thus increases blood glucose.
Glucagonomas are a type of pancreatic endocrine tumor that arises from the alpha cells of the pancreas. They are very rare but similar to other islet cell tumors in that the primary and metastatic lesions are slow-growing: 15-year survival is common. Most glucagonomas are malignant.
The average age at symptom onset is 50 years; 80% of patients are women. A few patients have multiple endocrine neoplasia type 1.
Symptoms and Signs of Glucagonoma
Because glucagonomas produce glucagon, which raises blood sugar, the symptoms are the same as symptoms of diabetes.
Frequently, weight loss, normochromic anemia, hypoaminoacidemia, and hypolipidemia are present.
The most distinctive clinical feature is a chronic eruption involving the extremities, often associated with a smooth, shiny, vermilion tongue and cheilitis. The exfoliating, brownish red, erythematous lesion with superficial necrolysis is termed necrolytic migratory erythema.
Diagnosis of Glucagonoma
Serum glucagon level
CT and endoscopic ultrasonography to localize
Most patients with glucagonoma have glucagon levels > 1000 pg/mL (> 1000 ng/L; normal is < 200 pg/mL [< 200 ng/L]). However, moderate elevations occur in renal insufficiency, acute pancreatitis, severe stress, and fasting. Correlation with symptoms is required.
Patients should have abdominal CT followed by endoscopic ultrasonography; MRI or positron emission tomography (PET) may be used if CT is unrevealing.
Treatment of Glucagonoma
Surgical resection for localized disease
Chemotherapy for metastatic disease
Resection of the tumor alleviates all symptoms.
glucagon
glucagon production and relieve the erythema, but glucose tolerance may also decrease because octreotide decreases insulin secretion. Octreotide may quickly reverse anorexia and weight loss caused by the catabolic effect of glucagonoctreotide may also need to take supplemental pancreatic enzymes because octreotide suppresses pancreatic enzyme secretion.
Locally applied, oral, or parenteral zinc may cause the erythema to disappear, but resolution may occur after simple hydration or IV administration of amino or fatty acids, suggesting that the erythema is not solely caused by zinc deficiency.
