Endocrine Abstracts

JOINT1663

Malignant insulinoma is a rare pancreatic neuroendocrine tumor that accounts for up to 10% of all cases of insulinoma and it is characterized by the presence of severe hyperinsulinemic hypoglycaemic syndrome which encompasses a short life expectancy and great morbidity. Therapeutic management is challenging due to the need to control both hypoglycemic syndrome and tumor growth. Curative surgery is rarely applicable due to widespread metastases. We report a clinical case with metastatic malignant insulinoma accompanied by a life-threatening, and refractory hypoglycemia that was early and adequately controlled with 177Lu-DOTATATE treatment. A 51-year-old man was referred to endocrinology for hypoglucemic episodes that evolve to severe and repeated with neuroglycopenic symptoms. 7 months prior to the referral, he had been diagnosed with a grade G1, stage IV pancreatic (PNET) gastrinoma and started on PPIs, lanreotide 120mg every 28 days and everolimus achieving stabilization of the pancreatic and hepatic lesions after 6 months of treatment. We suspected a switch in functioning syndrome so we proceeded to initiate treatment with diazoxide after we confirmed hyperinsulinemic hypoglycaemia. Despite everolimus diazoxide, lanreotide 120mg/28 days, Dexamethasone, continuous enteral nutrition and parenteral infusion of glucose iv drip therapy, the episodes did not subsided. After a multidisciplinary discussion, in which other treatment options as Pasiretiode were discussed, first dose of lutetium (Lu-177)-DOTA-Tyr3-octreotate (177Lu-DOTATATE) was administered. After 7 days, the number and severity of the hypoglucemic episodes decreased, and the need for glucose iv drip, enteral nutrition and Dexamethasone, and diazoxide progressively lessen and after the second dose the episodes subsided without the need of any additional treatment. In total he was treated with 4 doses of 177Lu-DOTATATE. Eleven months after the first dose of 177Lu-DOTATATE the patient continued without hypoglycemia and with normal serum proinsulin and insulin concentrations. A somatostain receptors scan with TC 99 after the fourth dose showed radiological stability of the lesions. The patient regained the sense of well-being and transitioned to working full-time. In our experience, the use of 177Lu-DOTATATE in the symptomatic disease it should be considered, to obtain a fast control of the functionality of the disease, improving the quality of life and apparent tumor growth stabilization.