We describe a case of a solid variant of serous cystadenoma of the pancreas. The preoperative examination results led to a diagnosis of a nonfunctional pancreatic islet cell tumour, and the patient underwent a pylorus-preserving pancreaticoduodenectomy. The tumour was diagnosed as a solid variant of serous cystadenoma by histopathological examination. Solid variant of serous cystadenoma of the pancreas is difficult to diagnose preoperatively. More cases must be accumulated and investigated to obtain clues for accurate diagnosis.