A Case of Colorectal Biliary Metastasis that Metastasized to the Bile Duct Epithelium and Grew Intrabiliary without Forming An Extrabiliary Mass

Abstract

An 81-year old woman underwent laparoscopic left hemi colectomy for transverse and descending colon cancer. In pathological examination, transverse colon lesion was diagnosed as tub2, pMP, ly0, v0, PM0, DM0, pN0, pStageI and descending colon lesion was pap, pMP, ly0, v0, PM0, DM0, pN1, pStageIIIA. In five years later after the operation, CT examination revealed a mass 1cm in size at liver S8. In the dorsal branch of B8, tumor thrombus was detected continuous from the mass. We diagnosed as metastatic liver cancer with bile duct tumor thrombus and performed partial liver S8 resection. In pathological examination, the tumor originated from the bile duct epithelium replaced by atypical cells proliferating into the bile duct. However, the mass did not invaded into liver parenchyma. The primary cholangiocarcinoma of intra biliary growth type and metastatic liver cancer with growth into the bile duct were identified as differential diagnosis. From the immunohistological findings: CK7 was negative, CK20 was negative and CDX-2 was positive, we diagnosed as colorectal biliary metastasis. We report this rare case of biliary metastasis from colorectal cancer that metastasized to the bile duct epithelium and grew into the bile duct without invasion of liver parenchyma.