Background: With the advances of imaging techniques, the detection rate of rare liver tumor is increased. However, the therapeutic strategies of the rare liver tumors remain limited.

Methods: We analyzed twelve pathologically confirmed rare liver tumors in 8 patients. All of the patients underwent ultrasound (US) guided biopsy and subsequent thermal ablation. The tumors were ablated according to the preoperative plans and monitored by real-time US. CT/MRI fused with contrast enhanced US (CEUS) or three-dimensional (3D) US-CEUS images were used to guide and assess the ablation zone more accurately during thermal ablation. The rate of technical efficacy was assessed based on the contrast-enhance CT/MRI (CECT/MRI) results one month after ablation. Local tumor progression (LTP), recurrence and complications were followed up and recorded.

Results: Among these twelve nodules, nine were subject to US-guided thermal ablation, whereas the other three inconspicuous nodules were subject to CEUS-guided thermal ablation. Intra-procedure CT/MRI-CEUS or 3D US-CEUS fusion imaging assessments demonstrated that the ablation zone sufficiently covered the original tumor, and no immediate supplementary ablation was required. Additionally, no major complications were observed during the follow-up period. The postoperative CECT/MRI confirmed that the technique success rate was 100%. Within the surveillance period of 13 months, no LTP or recurrence was noted.

Conclusions: US-guided thermal ablation was feasible and safe for rare liver tumors. The use of fusion imaging technique might make US-guided thermal ablation as effective as surgical resection, and this technique might serve as a potential therapeutic modality for rare liver tumors in the future.