Abstract
We report a case of biliary cystadenocarcinoma. A 59-year-old woman diagnosed with simple hepatic cyst elsewhere 2.5 years ago and admitted with abdominal discomfort was found in CT and MRI to have a cystic tumor 22 cm in diameter in the right hepatic lobe. The inner surface of the cystic tumor was smooth, and no suspected mural nodule was enhanced. Based on suspected biliary cystadenocarcinoma, we conducted right hepatic lobectomy. Macroscopically, the resected tumor was a simple hepatic cyst with no mural nodule or septum. Histopathologically, well-differentiated adenocarcinoma had spread flat to most of the cystic wall. A transitional portion from adenoma to adenocarcinoma suggested that this cystadenocarcinoma resulted from malignant transformation from cystadenoma. Asymptomatic hepatic cystic tumors are often found incidentally in mass screening. Biliary cystadenocarcinoma may, however, be difficult to distinguish from a simple hepatic cyst. The occurrence of hepatic cystic tumor should thus raise the possibility of biliary cystadenocarcinoma.
