AIM:To investigate the clinicopathologic features of bile duct tumor thrombus(BDTT) occurrence after treatment of primary small hepatocellular carcinoma(sHCC) .METHODS:A total of 423 patients with primary sHCC admitted to our hospital underwent surgical resection or local ablation.During follow-up,only six patients were hospitalized due to obstructive jaundice,which occurred 5-76 mo after initial treatment.The clinicopathologic features of these six patients were reviewed.RESULTS:Six patients underwent hepatic resection(n=5) or radio-frequency ablation(n=1) due to primary sHCC.Five cases had an R1 resection margin,and one case had an ablative margin less than 5.0 mm.No vascular infiltration,microsatellites or bile duct/canaliculus affection was noted in the initial resected specimens.During the follow-up,imaging studies revealed a macroscopic BDTT extending to the common bile duct in all six patients.Four patients had a concomitant intrahepatic recurrent tumor.Surgical re-resection of intrahepatic recurrent tumors and removal of BDTTs(n=4) ,BDTT removal through choledochotomy(n= 1) ,and conservative treatment(n=1) was performed.Microscopic portal vein invasion was noted in three of the four resected specimens.All six patients died,with a mean survival of 11 mo after BDTT removal or conservative treatment.CONCLUSION:BDTT occurrence is a rare,special recurrent pattern of primary sHCC.Patients with BDTTs extending to the common bile duct usually have an unfavorable prognosis even following aggressive surgery.Insufficient resection or ablative margins against primary sHCC may be a risk factor for BDTT development. AIM: To investigate the clinicopathologic features of bile duct tumor thrombus (BDTT) occurrence after treatment of primary small hepatocellular carcinoma (sHCC). METHODS: A total of 423 patients with primary sHCC admitted to our hospital underwent surgical resection or local ablation. Fluid follow -up, only six patients were hospitalized due to obstructive jaundice, which occurred 5-76 mo after initial treatment. clinicopathologic features of these six patients were reviewed .RESULTS: Six patients underwent hepatic resection (n = 5) or radio-frequency ablation (n = 1) due to primary sHCC. Patients had an R1 resection margin, and one case had an ablative margin less than 5.0 mm. No vascular infiltration, microsatellites or bile duct / canaliculus affection was noted in the initial resected specimens. the follow-up, imaging studies revealed a macroscopic BDTT extending to the common bile duct in all six patients. Patients with a concomitant intrahepatic recurrent tumor. Surgical re-resection of intrahepatic recurrent tumors and removal of BDTTs (n = 4), BDTT removal through choledochotomy (n = 1), and conservative treatment (n = 1) was performed. Microscopic portal vein invasion was noted in three of the four resected specimens. All six patients died, with a mean survival of 11 mo after BDTT removal or conservative treatment. CONCLUSION: BDTT occurrence is a rare, special recurrent pattern of primary sHCC. Patients with BDTTs extending to the common bile duct usually have an unfavorable prognosis even following aggressive surgery .Insufficient resection or ablative margins against primary sHCC may be a risk factor for BDTT development.