Glucagon is a peptide produced by the α cells of pancreatic islets. Tumors that produce excessive glucagon may lead to altered glucose tolerance and frank diabetes mellitus. In fact, new-onset type II diabetes in a thin patient older than age 60 years should prompt investigation into the presence of a pancreatic glucagonoma. If present, a characteristic skin rash, named necrolytic migratory erythema, is pathognomonic for glucagonoma4 and is present in two thirds of patients with glucagonomas. The rash consists of painful, pruritic lesions that begin as blistering, erythematous plaques and slowly spread outward. The edges appear to erode and then crust over. Hyperpigmentation may be seen at the location of a prior lesion. These lesions generally appear in areas subject to great friction and pressure, such as the perineum, lower abdomen, buttocks, and groin. Patients with glucagonomas often have other signs of nutritional deficiencies, such as hypoaminoacidemia and zinc deficiency. They may present with stomatitis, glossitis, cheilosis, and vulvovaginitis. Other symptoms may include weight loss, depression, and anemia that is normochromic and normocytic. Finally, patients with a glucagonoma may have a marked risk of hypercoagulability and deep venous thrombosis.