A 77-year-old man was pointed out thrombocytopenia and polycystic liver and kidney disease following hypertension and diabetes mellitus and duodenitis. He consulted to our hospital for further examination. Computed tomography (CT) showed multiple cysts in the liver and kidney and also showed cystic lesions in the pancreatic tail. The size of the tumor of pancreas was 3 cm × 4 cm. FDG-PET CT showed FDG uptake in the tumor of the pancreatic tail. It has not showed metastasis in the other organs. The examinations suggested that the cause of thrombocytopenia was infection of Helicobacter pylori or idiopathic thrombocytopenic purpura or drugs. We performed distal pancreatectomy for the tumor of pancreas. Histological findings revealed that the tumor of pancreas was invasive intraductal mucinous carcinoma. He had no recurrence for 3 months after operation. In this case, the patient with autosomal-dominant polycystic kidney disease (ADPKD) and multiple liver cysts developed IPMC. We suggest that some genetic interactions may exist between ADPKD and pancreatic carcinogenesis.