[A Patient with Multiple Endocrine Neoplasia Type1(MEN1)Presenting with Hypoglycemic Attacks]

Here, we report the case of a woman with multiple endocrine neoplasia type 1(MEN1) who experienced hypoglycemic attacks. At the age of 59, she underwent parathyroid tumor resection for hyperparathyroidism. At the age of 65, she presented with dizziness at our hospital. Magnetic resonance imaging (MRI) revealed a left cerebellopontine (CP) angle tumor and a pituitary tumor. The CP angle tumor (acoustic neurionoma) was removed;the pituitary adenoma (prolactinoma) was managed by using bromocriptine. At the age of 77, she lost consciousness and was transferred to a local hospital. Her blood sugar level was 24 mg/dL. Due to the frequent recurrence of hypoglycemic attacks, she was readmitted to our hospital. MRI revealed the almost complete removal of the acoustic tumor and that her pituitary gland was atrophied. Despite her baseline pituitary hormone levels being normal, we suspected panhypopituitarism and administered cortisol (15 mg/day). As her hypoglycemia failed to improve, we performed a 75-g oral glucose tolerance test, and its result was not indicative of diabetes mellitus. Her pretest immunoreactive insulin (IRI) level was 6.8μU/mL;ΔIRI/ΔBS was 0.62, indicative of insulin hypersecretion. Contrast-enhanced abdominal computed tomography revealed multiple pancreatic tumors (insulinomas), and she underwent resection of the uncal tumor and pancreas body and tail. Her postoperative IRI level was normalized and she experienced no further hypoglycemic attacks. Based on her hyperparathyroidism, pancreatic tumor, and pituitary adenoma, we diagnosed her with MEN1.