Needle track seeding after percutaneous ethanol injection therapy for small hepatocellular carcinoma

We present two cases of patients experiencing needle track seeding after undergoing percutaneous ethanol injection therapy (PEIT) for small hepatocellular carcinoma, who were treated by surgical resection of the metastases. One patient demonstrated metastatic tumors due to needle track seeding 6 months after the beginning of PEIT (a total of 7 injection sessions for 2 tumors measuring < 20 mm in diameters), whereas the other developed a metastatic tumor 20 months after beginning PEIT (a total of 30 injection sessions for 3 tumors measuring < 20 mm in diameter). In the two cases, both the primary and metastatic tumors histologically revealed moderately differentiated hepatocellular carcinoma. Moreover, the histological findings of the metastatic foci did not always appear to be more aggressive than those of the primary tumors. Therefore, in order to detect such metastasis as early as possible, more careful attention should be paid to the appearance of needle track seeding after performing PEIT for hepatocellular carcinoma, even if the target of such PEIT is small HCC.