INTRODUCTION: Radiofrequency ablation (RFA) is widely used to treat benign thyroid nodules. While pre-ablation cancer screenings can produce false-negatives, tumor seeding is rare, and aggressive thyroid cancers following RFA have not been reported. We present two cases of potential track seeding after RFA. CASE REPORT: The first patient is a 56-year-old female who developed anaplastic thyroid cancer, while the second is a 61-year-old female diagnosed with poorly differentiated thyroid cancer. Both had a history of RFA for presumed benign nodules, with cancer identified at the intervention sites. CONCLUSION: These cases highlight the need for thorough pre-treatment biopsy and careful needle handling during RFA. To date, no cases of cancer directly induced by RFA have been reported
therefore, it is likely that thyroid carcinoma coexisted at the time of the procedure or developed afterward. Early detection through regular follow-up could have prevented progression to aggressive disease. This emphasizes the importance of diligent post-procedural monitoring.