Late-occurring inflammatory process mimicking tumor recurrence following cryoablation for renal cell carcinoma: A case series.

Local tumor progression (LTP) is one of the concerning complications after cryoablation therapy for patients with early-stage renal cell carcinoma (RCC). Imaging findings of tumor recurrence following cryoablation for RCC typically include residual contrast enhancement or enlargement of the non-enhancing ablation zone. However, late-onset inflammatory changes-though rare-can mimic tumor recurrence. We present 3 cases, 74-year-old male, 86-year-old male and 70-year-old male, with RCC following cryoablation with initially suggested tumor recurrence, but later pathology proved to be late-onset inflammation. The key imaging feature is new peripheral enhancing soft tissue at the margin of the ablation zone, appearing at a mean interval of 84 months post-cryoablation-substantially later than the typical timeframe for Local tumor progression (LTP). All patients had well-controlled type 2 diabetes mellitus. Thus, in patients with a remote history of RCC cryoablation, peripheral enhancement at the ablation margin-rather than within the ablated tumor-on long-term follow-up may represent a late-onset inflammatory process rather than true recurrence.