Malignant glucagonoma of the pancreas diagnosed through anemia and diabetes mellitus

Abstract

Glucagonoma of the pancreas is a rare tumor with distinct clinical manifestations, such as necrolytic migratory erythema, weight loss, anemia, diabetes mellitus, and hypoamino-acidemia. We report the case of a 68-year-old Japanese man who underwent curative resection for malignant glucagonoma of the pancreas diagnosed through anemia and diabetes mellitus. The patient had had diabetes mellitus for 20 years. Anemia was diagnosed in 1998. On admission, the hemoglobin level was 8.3 g/dl, but the levels of serum iron, vitamin B12, and erythropoietin and, the number of reticulocytes were within normal limits. The levels of carcinoembryonic antigen (CEA), carbohydrate antigen (CA)19-9, and DUPAN-2 were also within normal limits, and exocrine function of the pancreas (PFD, 75%) was normal. Ultrasonography (US) revealed a hypoechoic tumor in the distal pancreas. Computed tomography (CT) demonstrated a high-density area 4 cm in diameter with calcification. The serum glucagon level was very high (2360 pg/ml), but the levels of other hormones such as somatostatin or gastrin were within normal limits, while insulin was low. Glucagonoma of the pancreas was diagnosed, and distal pancreatectomy with splenectomy was performed. Histological examination revealed a malignant endocrine tumor, which was immunohistochemically positive for chromogranin A and glucagon. Two months after the operation, the serum glucagon level had decreased to within normal limits and the hemoglobin level had increased to 10.4 g/dl. The case of glucagonoma reported here was found through diagnostic examinations of anemia and treated by surgical resection, by which the patient's anemia was largely alleviated. Therefore, we recommend checking patients who have diabetes mellitus and anemia in order to diagnose and treat glucagonoma in its early statge.