Mixed Neuroendocrine - Non-Neuroendocrine Neoplasm (MiNEN) - A Rare Heterogenous Malignancy of the Pancreas

Abstract

Introduction: Pancreatic mixed neuroendocrine non-neuroendocrine neoplasms are extremely rare tumours accounting for 0.5% of all the pancreatic malignancies and 5% of all pancreatic neuroendocrine neoplasms. These tumors are rarely diagnosed preoperatively and they have a poor prognosis. Pancreatic MiNEN is characterized by 2 malignant lesions adenocarcinoma and Neuroendocrine tumour with each constituent involving more than 30% of the tumour. We report a case of 57yr old male with dullaching abdominal pain radiating to back. CA 19-9 was mildly elevated. Other laboratory tests are within normal limits. CECT abdomen revealed bulky pancreas with specks of calcification in the head of the pancreas and few tiny non enhancing hypodense areas and a well defined isodense lesion measuring 1.2x1.4cm in the second part of duodenum with enhancement in post contrast images associated with thickness of duodenal wall. The patient underwent Whipple’s pancreaticoduodenectomy with regional lymphadenectomy. Histopathological examination of specimen revealed an infiltrating acinar adenocarcinoma of the pancreas interspersed with a well differentiated neuroendocrine tumour component which made up of more than 45% of the tumour. The features were consistent with Mixed Neuroendocrine Non Neuroendocrine Neoplasm of the pancreas. Keywords: MiNEN, Pancreas, Neuroendocrine, Non neuroendocrine, Adenocarcinoma