We report a case of bile duct cystadenocarcinoma.
A 69-year-old woman who had been observed for a hepatic cyst for about 5 years received close exploration because a papillary prominence in the hepatic cyst and debris like echo were revealed by abdominal ultrasonography in July 2002. On imaging methods, an about 8-cm sized cystic lesion mainly in the medial segment of the liver and an about 6-mm sized ridge on the cystic wall were visualized. Tumorous cyst or a cyst communicated with the bile duct was suspected and a puncture examination of the hepatic cyst was conducted. The content of the cyst was white translucent mucus and its cytological diagnosis resulted in class II. An extended left lobectomy was performed with a diagnosis of cystic hepatic tumor. The excised material revealed an about 8-cm sized monolocular cyst mainly locating in the medial segment of the liver with mucus in it. The cystic wall was smooth except a part at where the 6-mm sized palillary prominence was identified. Pathologically the cystic wall except the papillary prominence was covered with high columnar atypical epithelium, and was diagnosed as bile duct cystadenoma. Atypical cells predominated in the papillary prominence, where was diagnosed as cystadenocarcinoma. It is etiologically thought that cancer change had occurred in a part of the adenoma.