膵尾部癌の像を示した膵内副脾の1例

Intrapancreatic accessory spleens exhibit the same computed tomography （CT） findings as the spleen itself. We experienced a case in which an intrapancreatic accessory spleen mimicked pancreatic tail carcinoma. A ５４-year-old female who had a medical history of splenectomy presented with a pancreatic tail tumor, which exhibited low density in the arterial phase and slightly high density in the portal and equilibrium phases on CT. In addition, an accessory spleen was present in the greater omentum. We initially diagnosed the tumor as a pancreatic carcinoma, and scheduled distal pancreatectomy（DP）combined with lymph node dissection（LND）. Intraoperatively, the tumor was found to be elastic-soft, which indicated that it might be benign. We changed the planned procedure from DP combined with LND to DP without LND. The cut surface of the tumor had the appearance of spleen tissue, and the pathological diagnosis was an intrapancreatic accessory spleen. Intrapancreatic accessory spleens can display the same imaging findings as pancreatic carcinomas. Intraoperative palpation and gross pathological examinations were useful for selecting the optimal surgical procedure in the present case. It is important to differentiate pancreatic tail tumors that exhibit low density in the arterial phase on CT from accessory spleens.