Her symptoms had been worsening for 4 years despite specialized wound care. In addition, she noted concurrent weight loss, depression, abdominal pain, and intractable nausea. She was taking 500 mg of metformin daily. Given her history of diabetes mellitus and the skin findings, abdominal computed tomography was performed, and glucagon levels were measured.
An enhancing, lobulated mass measuring 7 cm in diameter was found in the tail of the pancreas, and the patient's fasting glucagon level was elevated, at 890 pg per milliliter (normal range, 0 to 80). The mass was resected, and pathological examination of the specimen confirmed a diagnosis of glucagonoma.
Glucagonomas are rare neuroendocrine tumors that can cause diabetes and a rash known as necrolytic migratory erythema, which has a characteristic annular pattern of erythema with central crusting and bullae. The prognosis correlates with the stage of tumor development and the potential for resection. In this patient, 1 day after resection, the rash had faded significantly. Four weeks after discharge, the patient had normal glucose levels (while taking no medication), and the necrolytic migratory erythema had completely resolved.