CLINICS 2012;67(S1):145-148 REVIEW DOI:10.6061/clinics/2012(Sup01)24 Surgical treatment of pancreatic endocrine tumors in multiple endocrine neoplasia type 1 Marcel Cerqueira Cesar Machado Faculdade de Medicina da Universidade de S a˜o Paulo, Department of Surgery, Sa˜ o Paulo/SP, Brazil. Surgical approaches to pancreatic endocrine tumors associated with multiple endocrine neoplasia type 1 may differ greatly from those applied to sporadic pancreatic endocrine tumors. Presurgical diagnosis of multiple endocrine neoplasia type 1 is therefore crucial to plan a proper intervention. Of note, hyperparathyroidism/multiple endocrine neoplasia type 1 should be surgically treated before pancreatic endocrine tumors/multiple endocrine neoplasia type 1 resection, apart from insulinoma. Non-functioning pancreatic endocrine tumors/multiple endocrine neoplasia type 1 .1 cm have a high risk of malignancy and should be treated by a pancreatic resection associated with lymphadenectomy. The vast majority of patients with gastrinoma/multiple endocrine neoplasia type 1 present with tumor lesions at the duodenum, so the surgery of choice is subtotal or total pancreatoduodenectomy followed by regional lymphadenectomy. The usual surgical treatment for insulinoma/multiple endocrine neoplasia type 1 is distal pancreatectomy up to the mesenteric vein with or without spleen preservation, associated with enucleation of tumor lesions in the pancreatic head. Surgical procedures for glucagonomas, somatostatinomas, and vipomas/ multiple endocrine neoplasia type 1 are similar to those applied to sporadic pancreatic endocrine tumors. Some of these surgical strategies for pancreatic endocrine tumors/multiple endocrine neoplasia type 1 still remain controversial as to their proper extension and timing. Furthermore, surgical resection of single hepatic metastasis secondary to pancreatic endocrine tumors/multiple endocrine neoplasia type 1 may be curative and even in multiple liver metastases surgical resection is possible. Hepatic trans-arterial chemo-embolization is usually associated with surgical resection. Liver transplantation may be needed for select cases. Finally, pre-surgical clinical and genetic diagnosis of multiple endocrine neoplasia type 1 syndrome and localization of multiple endocrine neoplasia type 1- related tumors are crucial for determining the best surgical strategies in each individual case with pancreatic endocrine tumors. KEYWORDS: MEN1; Pancreatic Tumors; Endocrine Tumors; Pancreatic Endocrine Tumors; Neuroendocrine Tumors. Machado MCC. Surgical treatment of pancreatic endocrine tumors in multiple endocrine neoplasia type 1. Clinics. 2012;67(S1):145-148 E-mail: mccm37@uol.com.br Tel.: 55 11 3289-1188 INTRODUCTION Pancreatic neuroendocrine tumors (PETs) originate from pancreatic islet tissue. Pancreatic endocrine tumors may produce clinical symptoms as a result of excessive produc- tion of one or more hormones such as gastrin, insulin, somatostatin, glucagon, and vasoactive intestinal polypep- tide (functioning PETs) or may be silent, producing only pancreatic polypeptides (non-functioning PETs). Multiple endocrine neoplasia type 1 (MEN1) is a complex inherited condition, which may comprise up to 20 different types of endocrine and non-endocrine tumors, although the three most prevalent conditions are hyperparathyroidism, PETs, and pituitary tumors (1). MEN1 leads to increased morbidity and mortality rates, mainly as a result of PETs and thymic carcinoids (1,2). Copyright 2012 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. No potential conflict of interest was reported. 145 PETs/MEN1 VERSUS S-PETs The PETs associated with MEN1 (PETs/MEN1) may differ markedly from sporadic PETs (S-PETs) and are characterized by: (i) an earlier disease onset; (ii) a propensity to present higher risk for malignancy; (iii) multiple tumor lesions scattered throughout the pancreas and duodenum, instead of a single pancreatic nodule as in S-PETs; (iv) variable hormone production; (v) most patients having a familial history of PETs; and (vi) most cases (,90%) harboring an inactivating germline mutation in the MEN1 tumor suppres- sor gene (1). Based on the clinical differences between PETs/ MEN1 and S-PETs, distinct surgical approaches are used for each of these conditions. Surgical treatment of tumor lesions in PETs/MEN1 may be controversial but its rationale is based on cure of the clinical syndrome and avoidance of malignant tumor progression (2). In MEN1 patients, primary hyperparathyroidism is fre- quently the first clinical manifestation and is usually the first condition to be surgically treated. This was recently verified in a large MEN1 family caused by a founding MEN1 gene mutation (3,4). The reduction in calcium/parathyroid hor- mone serum levels after total parathyroidectomy followed by