Clinical and metabolic aspects of glucagonoma

The features of 41 proven or suspected cases of pancreatic glucagonoma and one possible case of renal glucagonoma have been reviewed. Glucagonoma is one form of islet cell neoplasm and involves pancreatic alpha cells. It may occur more frequently in women and is more likely to be malignant than insulinoma. Patients may present with glucose intolerance, an erythematous, eczematous dermatitis, glossitis, stomatitis, vaginitis and unexplained weight loss. Anemia, hypoproteinemia, hypoaminoacidemia and hypolipidemia may also be present. Malignant glucagonoma metastasizes frequently to liver. An evaluation for possible glucagonoma may be considered in a patient with the characteristic eczematous dermatitis, glossitis or stomatitis and glucose intolerance, an unusual or atypical history of diabetes mellitus, or hepatomegaly with other characteristics of glucagonoma. Initial evaluation may include measurement of fasting plasma glucagon concentration, and an oral glucose tolerance test with measurements of plasma glucose and glucagon levels. Extreme fasting hyperglucagonemia, and a paradoxical rise in plasma glucagon concentrations after glucose ingestion should strongly suggest the presence of glucagonoma. Radiographic demonstration of pancreatic glucagonoma is best carried out by celiac arteriography. Surgical excision of the tumor is the treatment of choice. Nonresectable lesions may respond to chemotherapy with streptozotocin. Treatment for the various dermatologic or metabolic complications of glucagonoma which include glucose intolerance, hypoproteinemia, hypocholesterolemia and anemia may not be satisfactory. Glucose intolerance is usually mild and may be adequately treated with dietary or insulin therapy. Rarely, glucagonoma with massive destruction of the pancreas or other factors may induce severe glucose intolerance. In contrast, the anemia, skin rash, and hypoproteinemia do not respond to conservative therapies tested thus far. Glucagonoma is a model for studying the importance of glucagon in causing the hyperglycemia of diabetes mellitus. Study of patients with glucagonoma does suggest that glucagon has some role in the etiology of hyperglycemia in diabetic states; however, as in studies on diabetes, investigations on glucagonoma do not demonstrate that glucagon has a primary role in producing severe glucose intolerance.