A case series of neoplastic seeding after cryoablative treatment for renal masses

Aim of the study: To report incidence of tumor cell seeding in patients with small renal masses who underwent percutaneous cryoablative treatment. Materials and methods: We retrospectively reviewed data stored in a prospectively maintained database of patients who underwent CT- guided percutaneous cryoablative treatment of SRMs in our tertiary referral center between June 2011 and February 2018. The resulting imagings were reviewed by our institutional multidisciplinary team with particular interest in cases of recurrences along the needle tract of the cryoprobe. Results: During the study period, 110 patients were treated using Perc- 17 probes (Galil Medical). 56 masses were histologically-proven malign RCC, 36 were benign lesions, in 8 cases biopsies were non- diagnostic and in 10 cases biopsy was avoided. Mean follow-up of the entire cohort was 31,04 months (IQR:12,5–39,8). 2 cases of needle tract seeding were identified during the follow-up. Case1: A 47-yo male presenting asymptomatic haematuria. CT scan revealed a 35 mm right complex cystic mass. Open NSS was performed without cystic rupture and a diagnosis of pT1a R0 Fuhrman G1 ccRCC was given. 2 years later the patient developed a 18 mm contrast-enhanced cyst, and under- went cryoablation treatment. No biopsy was performed to prevent the risk of cystic rupture. After 12 months, MRI revealed an intramuscular recurrence along the needle tract, which was surgical removed. A diagnosis of undifferentiated RCC was given. Patient developed metastatic disease in 3 months and despite additional treatment, the tumour induced death 6 months later. Case 2: A 72-yo male with solitary kidney for previous right RN (pRCC, type 1, 2002), diagnosed with left renal recurrence and treated with open NSS (2007, pRCC). In October 2017 the patient underwent cryoablative treatment for an inferior polar 14 mm mass. At 3 months follow-up CEUS and MRI demonstrated 3 solid lesions into perinephric fat, and lumbar muscle consistent with recurrences. Biopsy was obtained with a 20-gauge needle and sample was consistent with pRCC. Patient refused further surgical treatment. In January 2018, he underwent a percutaneous cryoablative treatment of the recurrences in an effort to preserve renal function. To date, no recurrence was detected. Discussion: Over the recent years, use of cryoablation for the treatment of small renal tumor is increasing and it is likely that this will rise further. This article’s objective is absolutely not to deter clinicians from using cryoablation to treat SRMs. Cryoablation is helping patients and surgeons to avoid the concrete risks produced by surgery and anesthesia for unnecessary intervention. Nevertheless, unfortunately, tumor seeding seem not anecdotal as previously stated. Finally, we emphasize the importance of careful inspection of the perinephric fat, the posterior abdominal wall, the subcutaneous fat and other tissues along the ablation probe tract during oncological surveillance in order to treat possible cases of tumor seeding as early as possible.