Metastatic MEN1 Syndrome Treated with Lutetium-177 – A Case Report

Abstract Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant endocrine tumour syndrome characterised by three main manifestations: primary hyperparathyroidism (78–94%), gastroenteropancreatic neuroendocrine tumours (GEP-NETs) (35–78%) and pituitary adenomas (20–65%). For metastatic and inoperable GEP-NETs, there are some interventional and medical therapies. Peptide receptor radionuclide therapy (PRRT) with Yttrium-90 (90Y) and Lutetium-177 (177Lu) is one of the important radiotherapies. Herein we describe a case of MEN1 syndrome with inoperable metastatic GEP-NETs who had excellent response to the treatment with six cycles of 177Lu-DOTATATE. The patient was admitted to our clinic with widening of hands and feet, polyuria, polydipsia, nausea, vomiting and constipation. His laboratory and screening findings were consistent with primary hyperparathyroidism, acromegaly, secondary hypogonadism and central diabetes insipidus. He underwent 3.5 parathyroidectomy and hypophysis adenomectomy. Under treatment with lanreotide and cabergoline, he developed metastatic duodenal NET. PRRT with 177Lu-DOTATATE was administered in six cycles and an excellent response was displayed without any side effect. In conclusion, the dramatic response of the patient to PRRT with 177Lu-DOTATATE, described in our case report and recent published articles indicating the beneficial efficacy and limited adverse effects of 177Lu-DOTATATE, should encourage clinicians to use PRRT for inoperable or metastatic NETs.