7085 Myoclonus Seizure with Pseudo-Adrenal Insufficiency as the Clinical Manifestations Leading to the Diagnosed Multi-focal Insulinomas that Mimic Multiple Endocrine Neoplasia Type 1 Syndrome

Abstract Disclosure: P. Kiatpanabhikul: None. Background: Insulinoma is a rare disease that presents with varying symptoms and can be sporadic or associated with hereditary syndromes (1). These rare points of views of insulinoma-patient on clinical manifestations, hormonal responses and surgical pathology result for final diagnosis and management. Clinical Case: A 59-year-old woman presented with myoclonic seizure of right arm with consciousness duration 5-10 minutes every midday twice a week for 6 months and generalized convulsion for 20 minutes ago. She had a low FPG level (59 mg/dL; n 70-100) and was admitted to doing 72-hour fasting test that revealed hypoglycemia at 12-hour of fasting with a nadir glucose level of 55 mg/dL, insulin 3.7 uIU/mL (cutoff > 5), C-peptide 0.4 ng/mL (cutoff > 0.6), cortisol 6.22 mcg/dL (n 5-25) and normal morning ACTH level (29.8 pg/mL; n 10-65). These were appropriated response of endogenous insulinemia with inappropriate response of serum cortisol level in hypoglycemic feature. MRI pituitary gland was considered to evaluate secondary hypocortisolism which showed a small less enhancing lesion left anterior lobe 0.3x0.45-cm without any pituitary hormonal abnormalities that were considered non-functioning pituitary microadenoma which could not explain inappropriate response of cortisol level to hypoglycemic period in this patient. Five months later, she presented at the emergency room with myoclonic seizure on her extremities, blurred consciousness and slurred speech after having lunch for 1-2 hour and revealed CPG 30 mg%, severe hypoglycemia (26 mg/dL), hypocortisolism (4.49 mcg/dL), with endogenous hyperinsulinemia (insulin 55.2 uIU/mL, C-peptide 2.5 ng/mL). 250-mcg ACTH stimulation test was done and showed normal response of her HPA-axis function (serum cortisol level at 0, 30, 60 min was 9.12, 17.87, 18.61 mcg/dL). CT pancreatic protocol showed several arterial enhancing nodules scattering at pancreatic tails isoattenuation to pancreatic parenchyma on portovenous phase up to 1.7*1.6 cm. She was operated on to distal pancreatectomy with intraoperative insulin/glucose ratio monitoring. Surgical pathology confirmed 4-well-differentiated pancreatic neuroendocrine tumors with insulin-producing, sizes 0.5-1.7 cm in diameter. Her final diagnosis was multi-focal insulinomas with non-functioning pituitary microadenoma that mimic MEN-1 syndrome without secondary adrenal insufficiency. She underwent successful surgical resection with complete resolution of symptoms during 4 years of followed-up with no recurrence and no having any hypercalcemia and hyperprolactinemia. Conclusion: Multi-focal insulinomas can be presented as sporadic, more severe hypoglycemia and endogenous hyperinsulinemia during period after meal with myoclonic seizure and pseudo-adrenal insufficiency in older-aged, non-diabetes person without recurrence after treatment for 4-year of followed-up. Presentation: 6/2/2024