Neuroendocrine tumor within the tail of pancreas is commonly mistaken by imaging studies for intrapancreatic accessory spleen. Herein, we report a case of neuroendocrine tumor that mimicked accessory spleen on imaging studies, but eventually confirmed as neuroendocrine carcinoma after laparoscopic distal pancreatectomy. A 70-year-old Korean man was admitted for a lung mass in the right lower lobe. During evaluation, however, a mass lesion was incidentally found in pancreatic tail on abdominal CT scan. This 2.6 cm sized pancreatic tail mass showed T2 high signal intensity and T1 low signal intensity, along with T2 bright high signal intensity indicating the presence of cystic portion. Radiologic impression was neuroendocrine tumor or accessory spleen rather than metastasis from lung cancer. Therefore, he underwent concurrent operation of right lower lobe wedge resection and laparoscopic distal pancreatectomy. The result of the immunohistochemistry for pancreatic mass was as follows: synaptophysin (＋), CD56 (＋), chromogranin A (＋), Ki-67 index (3-4%). Based on these findings, the patient was diagnosed with well-differentiated endocrine carcinoma of the pancreas.