Abstract
On admission, a 78-year-old man with lower abdominal pain, was found to have a cystic tumor 30 mm in diameter with an intracystic elevated mass in the left medial section of the liver by US and CT. MRI and enhanced US revealed a multilocular cystic tumor with an enhanced elevated lesion. DIC-CT showed mild stenosis of the left hepatic duct, but mucin was not recognized in the bile duct. These findings suggested a cystic neoplasm of the liver, and the patient underwent left hepatic lobectomy. Histopatological examination revealed a multilocular tumor composed of papillary, mucin-producing neoplastic epithelium with various degrees of atypia and the tumor communicated to the bile ducts. Immunohistochemically, the neoplastic epithelium was partly positive for MUC1, MUC5AC and MUC6, but negative for MUC2. The tumor was a mucin-producing bile duct tumor which resembled branch duct type intraductal papillary mucinous neoplasm (IPMN) of the pancreas.
