A 77-year-old woman was admitted suffering from fever and headache. On laboratory examination, bacterial meningitis and sepsis due to Klebsiella pneumoniae were diagnosed. In addition, a hepatic cystic lesion measuring 13 cm in diameter in the left lobe was indicated on diagnostic imaging. After treatment with antibiotics, her signs of infection improved and the hepatic lesion decreased in size. After discharge, however, the cystic liver mass increased and a gastric fistula developed. Hepatic and gastric resections were performed because of the possibility of biliary cystadenocarcinoma and gastric invasion. Pathologically, a pyogenic liver abscess complicated by gastric fistula was diagnosed.