Needle track seeding after radiofrequency ablation for hepatocellular carcinoma: prevalence, impact, and management challenge Giampiero Francica Interventional Ultrasound Unit, Department of Radiology, Pineta Grande Hospital, Castel Volturno, Italy Abstract: Neoplastic seeding may arise after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). A low risk of seeding after RFA (0–1.1%) has been reported, which may rise up to 2.5% if ablation followed diagnostic biopsy. Needle track seeding presents with one or multiple rounded nodules along the needle track located within the peritoneum, along the abdominal muscles, which were penetrated by the needle, pleural surface, or in the subcutaneous and cutaneous tissues. The most widely used method for the assessment of seeding nodules is ultrasound (US), which usually displays hypoechoic nodules with intralesional vascularization. Fine needle aspiration biopsy of the nodule suspicious for malignant implant is mandatory to confirm the diagnosis and plan therapy. Wide surgical excision is the treatment of choice for neoplastic seeding. Thanks to early diagnosis and prompt treatment, development of needle track seeding is not likely to affect the long-term survival of patients. Keywords: ablation, biopsy, liver, seeding, HCC