Extensive lymph node dissection of the hepatic pedicle was undertaken in 100 consecutive patients undergoing curative hepatectomy for colorectal liver metastases in whom lymph node involvement of the hepatic pedicle was not macroscopically detectable. Microscopic lymph node involvement was found in 14 patients, in very different lymph node sites, and was related only to the number of metastases, extent of liver involvement and carcinoembryonic antigen level (all P < 0.05).