Pancreatic serous cystadenomas account for 1-2% of all exocrine pancreatic tumors, and endocrine tumors account for 1-2% of all pancreatic neoplasms. The combination of pancreatic serous cystadenoma and endocrine tumor is even rarer. Here, we report two cases of combined pancreatic serous adenoma and endocrine tumor. One was a 64-year-old woman with serous cystadenoma and pancreatic endocrine tumor. The other case was a 28-year-old woman with von Hippel-Lindau disease with combined pancreatic serous oligocystic adenoma and well-differentiated malignant endocrine carcinoma. Reviewing the literature, we found 15 similar cases that showed two different age distributions and clinical presentations. Careful examination of benign serous cystadenoma should be kept in mind during clinical practice, to rule out the possibility of combined malignant endocrine tumor. In addition, von Hippel-Lindau disease should also be suspected when a young adult presents with combination of pancreatic serous cystadenoma and endocrine tumor.