CYSTIC GLUCAGONOMA WITH LOSS OF HETEROZYGOSITY ON CHROMOSOME-11 IN MULTIPLE ENDOCRINE NEOPLASIA TYPE-1

A 52-year-old man with a past history of a pituitary adenoma and hyper parathyroidism due to a parathyroid adenoma was admitted because of a solitary tumour of the pancreas revealed by ultrasonography. His famil y history was unremarkable. Plasma glucagon levels were slightly eleva ted (280 ng/l, normal range, 40-180 ng/l) with decreased plasma amino acid levels. Plasma glucagon levels disclosed an exaggerated response during an arginine infusion test and paradoxical elevation during a 75 g oral glucose tolerance test. Endoscopic ultrasonography revealed a monolocular cystic mass of about 3 cm in diameter in the body of the p ancreas. A pancreatic tumour was diagnosed before surgery as a cystic glucagonoma. Intra-operative ultrasonography showed one cystic mass in the body of pancreas and two other solid tumours, about 1 cm and 0.5 cm in diameter, in the tail of the pancreas. Histologically, all three tumours showed neoplastic epithelial cells with round nuclei forming cords and/or a ribbon-like arrangement. They showed positive staining for Grimelius' silver stain and immunopositive cells for glucagon. Gen etic analysis of the main cystic tumour revealed loss of heterozygosit y (LOH) on chromosome 11. After the operation, the responses of plasma glucagon to arginine infusion and oral glucose became normal. Here we describe the usefulness of these provocation tests for early diagnosi s and post-operative follow-up in a rare cystic glucagonoma associated with multiple endocrine neoplasia type 1 (MEN 1) which had LOH on chr omosome 11.