In March, 2004, a 64-year-old man was given a diagnosis of IPMN of the pancreas in postoperative CT of left shoulder blade chondrosarcoma. In October, 2007, because a tumor in the pancreas body was found, distal pancreatectomy was performed a diagnosis of the poorly differentiated adenocarcinoma. Histopathologic diagnosis revealed as pancreatic endocrine tumor and immunity dyeing was useful for differential diagnosis. A case of pancreatic endocrine tumor developing from IPMN has a possibility not rare for frequency, but few reports are available so far.