BACKGROUND/AIMS: This study aimed to evaluate the usefulness of immunohistochemical combinations for discrimination between intraepithelial ductal spread of colorectal carcinoma liver metastasis (CRLM) and that of intrahepatic cholangiocarcinoma (ICC). METHODOLOGY: A retrospective analysis of resected specimens from 151 patients with CRLM and 28 patients with ICC was conducted. Intraepithelial ductal spread along the bile ducts was judged positive when tumor cells spreading along the intact basement membranes of intrahepatic bile ducts. We evaluated immunoreactivity of cytokeratin (CK) 7, CK20, CDX2, MUC2, MUC5AC and human gastric mucin (HGM). RESULTS: Of the 151 patients with CRLM, 21 had intrahepatic bile duct involvement verified histologically. Intraepithelial ductal spread was detected in 17 of 21 (81%) patients with CRLM with bile duct involvement, whereas it was detected in 22 of 28 (79%) patients with ICC. CK20-positive/ CK7-negative immunophenotype demonstrated a high accuracy of 95% for evaluation of intraepithelial ductal spread from CRLM. CK7-positive/ CK20-negative immunophenotype demonstrated the highest accuracy of 85% for evaluation of intraepithelial ductal spread from ICC. CONCLUSION: Intraepithelial ductal spread is a common feature of CRLM with bile duct involvement. Immunohistochemical combination of CK7 and CK20 is useful for discrimination between intraepithelial ductal spread of CRLM and that of ICC.
BACKGROUND/AIMS: This study aimed to evaluate the usefulness of immunohistochemical combinations for discrimination between intraepithelial ductal spread of colorectal carcinoma liver metastasis (CRLM) and that of intrahepatic cholangiocarcinoma (ICC). METHODOLOGY: A retrospective analysis of resected specimens from 151 patients with CRLM and 28 patients with ICC was conducted. Intraepithelial ductal spread along the bile ducts was judged positive when tumor cells spreading along the intact basement membranes of intrahepatic bile ducts. We evaluated immunoreactivity of cytokeratin (CK) 7, CK20, CDX2, MUC2, MUC5AC and humangastric mucin (HGM). RESULTS: Of the 151 patients with CRLM, 21 had intrahepatic bile duct involvement verified histologically. Intraepithelial ductal spread was detected in 17 of 21 (81%) patients with CRLM with bile duct involvement, whereas it was detected in 22 of 28 (79%) patients with ICC. CK20-positive/ CK7-negative immunophenotype demonstrated a high accuracy of 95% for evaluation of intraepithelial ductal spread from CRLM. CK7-positive/ CK20-negative immunophenotype demonstrated the highest accuracy of 85% for evaluation of intraepithelial ductal spread from ICC. CONCLUSION: Intraepithelial ductal spread is a common feature of CRLM with bile duct involvement. Immunohistochemical combination of CK7 and CK20 is useful for discrimination between intraepithelial ductal spread of CRLM and that of ICC.