I had this exact thing n happen about 2 years after a 1.8cm mass on my kidney was ablated. Eventually the area showed some changes that were felt to be a fat necrosis until about 6 months later signs of enhancement were found on scan. Now monitoring continues in the 1.2 cm mass and surgical removal will likely happen. But mine is on a kidney. As long as no sign of enhancement is found probability of malignancy is lower. Continued monitoring with scans every 3-6 months may be recommended.