[Multiple Endocrine Neoplasia Type 1(MEN1)Presenting with Hypoglycemic Attacks - A Case Report].

A woman in her 60s visited our hospital because of frequent hypoglycemia and episodes of unconsciousness over the last 6 years. A 4 cm tumor was detected on the pancreatic tail using abdominal computed tomography and ultrasonography. An insulinoma was strongly suspected from the results of the fasting test and glucagon load test, and a distal pancreatectomy with splenectomy was performed. Pathological examination indicated an insulinoma and neuroendocrine tumor(NET)G2 based on the WHO 2010 classification. The patient's blood sugar and insulin levels returned to normal, and hypoglycemic attacks disappeared postoperatively. Six months later, a total parathyroidectomy was performed because of primary hyperparathyroidism with hypertrophy of the parathyroid glands. Furthermore, pituitary swellingwas also detected usinghead MRI. However, the patient has been under observation because the tumor was non-functional without any associated symptoms. Thus, we diagnosed the patient with multiple endocrine neoplasia type 1(MEN1). In patients with pancreatic NET, it is necessary to consider the possibility of MEN1.