To report a case where the guideline-defined ablation margin was absent during and shortly after microwave ablation of a solid lung nodule.
Approach:
Case Description: A 59-year-old woman with a metastatic solid lung nodule underwent microwave ablation using a single antenna, with a total treatment time of 8 minutes at 45 W.
Imaging and Findings: Imaging performed 21 minutes post-ablation showed no circumferential increased-attenuation margin, only slight expansion of the solid-attenuation region.
Delayed Margin Appearance: A sharply demarcated margin was observed 30.5 hours post-ablation, with significant consolidation noted, and a cavity formed by day 32.
Key Findings:
No guideline-defined margin was visible immediately after ablation despite adequate energy delivery.
The absence of the margin should not automatically prompt further ablation.
A delayed emergence of the margin was observed.
Limitations:
The study is based on a single case, limiting generalizability.
Lack of equivalent evidence for solid nodules regarding margin appearance and management.
