Calcitonin-Secreting Pancreatic Neuroendocrine Tumor in a Patient with Multiple Endocrine Neoplasia Type 1

ABSTRACT Objective: To present a patient with multiple endocrine neoplasia type 1 (MEN1) syndrome recently diagnosed with a calcitonin-secreting pancreatic neuroendocrine tumor. Methods: Clinical and diagnostic evaluation, along with intervention, is presented. The relevant literature is reviewed. Results: The patient was a 52-year-old Caucasian man with a history of known MEN1 who had a right parathyroidectomy 10 years prior to admission, completion parathyroidectomy and total thyroidectomy for C cell hyperplasia 3 years prior, and removal of a pituitary adenoma 4 years prior. He was asymptomatic but had persistently elevated serum calcitonin levels. Venous sampling and positron emission tomography–computerized tomography indicated several lesions in the pancreas as the most likely cause of ectopic calcitonin secretion. The patient underwent pylorus-sparing pancreaticoduodenectomy (Whipple procedure). Several well-differentiated neuroendocrine lesions of the pancreas were noted, with lymphatic invasion and spread to a peripancreatic lymph node. Postoperatively, the patient's calcitonin levels returned to the normal range. Conclusion: Calcitonin-secreting pancreatic neuroendocrine tumors are relatively rare entities that are even more rare in familial syndromes such as MEN1. Due to the clinically silent nature of these lesions, they are often discovered incidentally and late in their clinical course. More data are needed in order to establish a consensus on ideal management. Calcitonin elevation even in MEN1 may herald non-thyroid malignancy, therefore demanding an aggressive approach to evaluation and treatment. Abbreviations: CT computerized tomography; MEN1 multiple endocrine neoplasia type 1; PNETs pancreatic neuroendocrine tumors; PP pancreatic polypeptide; VIP vasoactive intestinal peptide