Intrahepatic renal cell carcinoma implantation along a percutaneous biopsy and cryoablation probe tract

Abstract

A man in his 60s underwent percutaneous biopsy and cryoablation of a right upper pole clear cell renal cell carcinoma followed by repeat cryoablation 8 months later for possible residual disease. The patient was followed with imaging with documented stability for 19 months after repeat ablation. However, imaging at 32 months demonstrated intrahepatic nodular enhancing lesions along the initial percutaneous biopsy and ablation tract, consistent with metastatic implantation. The patient underwent repeat percutaneous biopsy and two rounds of microwave ablation for treatment of the intrahepatic implants, with no residual disease at 10 months postablation. While needle tract seeding is a known complication of percutaneous manipulation of various abdominopelvic malignancies, there have been no prior reports of intrahepatic metastatic implants related to percutaneous renal cell carcinoma ablation. Awareness of this potential complication is important for treatment planning, informed consent and surveillance. This report shares our experience of the management of intrahepatic metastatic implants.

Background

Treatment options for early-stage renal cell carcinoma are variable, based on both patient and tumour factors, and generally include surgical resection (SR) and percutaneous thermal ablation (PTA). Retrospective analyses suggest that treatment outcomes of PTA are comparable to SR and are associated with a lower incidence of perioperative complications as well as improved long-term preservation of renal function.^1–3 Although some studies have suggested a higher comparative rate of local recurrence with PTA,¹ the minimally invasive technique makes it an appealing treatment option, particularly in medically compromised patients who are poor surgical candidates. While PTA is generally well tolerated, there are nonetheless risks associated with the technique, including the risk of metastatic implantation along the needle probe tract. The reported rates of metastatic seeding with percutaneous biopsy are very low,^4–8 and rates vary with the histopathological subtype of the tumour.⁹ Although the risk is minimal, there are numerous studies and case reports available which describe such instances involving various malignant abdominopelvic tumours, including renal cell carcinoma.^10–15 There are, however, very few reports describing metastatic seeding of a probe tract following percutaneous ablation of renal cell carcinoma.^15–17 In these reported cases, the sites of metastatic implantation after renal cell carcinoma ablation include retroperitoneal and subcutaneous adipose tissue. Our case report, however, describes a unique case of metastatic implantation within the liver in a patient who underwent percutaneous biopsy and cryoablation of a right upper pole renal mass. To our knowledge, there are no prior cases reported in the literature of metastatic renal cell carcinoma seeding to the liver after PTA. In addition to this rare phenomenon, we describe successful subsequent management of the intrahepatic metastatic implants with repeat percutaneous ablation.

Case presentation

A man in his early 60s with a history of multiple comorbidities, including coronary artery disease, Hepatitis C, chronic obstructive pulmonary disease, pulmonary embolism and obesity, was incidentally found to have a 1.1 cm solid right upper renal pole mass on abdominal CT performed for right upper quadrant abdominal pain. A follow-up CT 7 months later demonstrated interval growth of the lesion, highly suggestive of renal cell carcinoma (figure 1).

Figure 1.

Axial (A) and coronal (B) venous phase abdominal CT images demonstrating a 2.7 cm, mildly enhancing, partially exophytic right upper pole renal lesion, which was noted to have shown interval growth compared with prior imaging, concerning for renal cell carcinoma.

Treatment

Following discussion of the CT findings, the patient elected for treatment with percutaneous ablation and underwent simultaneous CT-guided biopsy and cryoablation of the right upper pole lesion (figure 2). CT-guided, juxtahepatic biopsy of the renal lesion was performed first using a coaxial technique with a 16 G coaxial introducer and 18-guage biopsy needle; a total of three biopsy specimens were obtained. Prior to ablation, an attempt was made to hydrodissect the liver away from the upper pole; however, this was relatively unsuccessful and was stopped due to poor patient tolerance. A single juxtahepatic ablation probe (Gallil Medical IceForce) was advanced along the same tract as the biopsy needle and cryoablation was performed using two 15 min freeze cycles followed by 8 min passive thawing periods. The patient tolerated the procedure well and was discharged home the same day. Pathology from the biopsy revealed a diagnosis of clear cell renal cell carcinoma. A follow-up CT scan performed 3 months later demonstrated a small area of residual enhancement at the inferior aspect of the ablation zone. Additional follow-up at 6 months demonstrated persistent mild enhancement in the inferior ablation zone, concerning for possible residual disease. After discussion with the patient, a decision was made to undergo repeat cryoablation. Repeat cryoablation was performed 8 months following the initial treatment. During the procedure, a single cryoablation probe (Gallil Medical IceForce) was used to perform two 15 min freeze cycles followed by 8 min thaw periods at the inferior aspect of the lesion, followed by needle repositioning and two additional ablative cycles at the more medial aspect of the lesion. Follow-up abdominal CTs over the next 19 months demonstrated no evidence of residual or recurrent disease. On a follow-up CT 32 months after the repeat cryoablation, however, the patient was noted to have multiple (at least 10) hyperenhancing lesions extending along the posterior serosal aspect of the right hepatic lobe, suggestive of metastatic implantation along the initial biopsy and cryoablation tract (figure 3). Two months later, the patient underwent CT-guided biopsy and microwave ablation of the suspected liver metastases (figure 4). The biopsy resulted clear cell renal cell carcinoma, confirming metastatic implantation as the aetiology. A 1-month follow-up CT scan demonstrated several areas of persistent nodular enhancement at the periphery of the ablation zone. The patient underwent repeat microwave ablation 1 month later.

Figure 2.

CT-guided percutaneous, transhepatic biopsy of the right upper pole renal lesion (A). CT-guided percutaneous, transhepatic cryoablation probe with distal tip within a right upper pole renal lesion (B). Notably, the cryoablation probe is directed along the same tract as the biopsy needle.

Figure 3.

Axial (A) and coronal (B) venous phase abdominal CT images demonstrating multiple small hyper-enhancing hepatic nodules along the posterior aspect of the liver (arrow), along the prior percutaneous biopsy and cryoablation tract, suggestive of metastatic tumour implantation.

Figure 4.

Axial non-contrast abdominal CT image demonstrating radiofrequency ablation probe during initial radiofrequency ablation (RFA) treatment of metastatic hepatic nodules.

Outcome and follow-up

Follow-up abdominal CTs at 6 weeks, 6 months and 10 months after repeat ablation (54 months after initial treatment) demonstrated no residual or recurrent disease (figure 5). Unfortunately, while the patient was undergoing surveillance imaging for renal cell carcinoma, he was diagnosed with metastatic small cell lung cancer. Treatment of his primary lung malignancy was futile, and he eventually elected palliative treatment and hospice placement. He subsequently passed away.

Figure 5.

Axial (A) and coronal (B) arterial phase abdominal CT images demonstrating resolution of hepatic metastases after radiofrequency ablation treatment.

Discussion

Although the risk of percutaneous biopsy-associated metastases of renal cell carcinoma has not been firmly quantified, the risk associated with the procedure is reportedly extremely low, <0.01%.^4–6 While there have been several reported instances of metastatic tract seeding associated with percutaneous ablation of primary and metastatic hepatic tumours,^10–12 there are relatively few case reports available which describe such a phenomenon involving primary renal cell carcinoma.^15–17 In the accounts documented in the available literature, authors describe postablation implants within the retroperitoneal fat and subcutaneous tissues along the probe tract. To our knowledge, there are no prior reports documenting renal cell carcinoma tract seeding within the liver, suggesting that this is an extremely rare phenomenon. This may in part be due to less common use of a transhepatic biopsy and ablation approach, which nevertheless is an acceptable route widely used by interventional radiologists, or due to other physiologic factors, which affect renal cell carcinoma micrometastases. And while liver metastases do occur in up to 20% of patients with renal cell carcinoma, this is typically a result of haematogenous spread, rather than local tumour spread or seeding.¹⁸ The presented case is curious in that the patient underwent percutaneous biopsy directly preceding percutaneous cryoablation along a similar juxta-hepatic tract, mudding the waters as to the aetiology of his implanted hepatic metastases. However, regardless of the aetiology of our patient’s metastatic implants, this case illustrates the very real phenomenon of metastatic implantation resulting from percutaneous renal tumour manipulation. Currently, percutaneous biopsy of renal masses is recommended by the American Urological Association (AUA) for all patients prior to treatment with PTA,¹⁹ and, therefore, it is imperative that the risk of metastatic seeding be considered and discussed with patients when discussing management options.

Metastatic seeds along a percutaneous tract are typically surgically excised whenever feasible; however, percutaneous ablation of retroperitoneal implants has also been reported.¹⁴ In our patient, tumour excision via partial hepatectomy was technically possible, however, given the patient’s multiple medical comorbidities, excision was not felt to be the best treatment option. The literature on prognosis of patients with tract seeding is generally limited due to the rarity of this complication. A review of 16 cases of metastatic renal cell carcinoma seeding along a percutaneous biopsy tract between 1977 and 2016 describe detection of tract seeding ranging anywhere from 3 weeks to 7 years after percutaneous biopsy.²⁰ Of these 16 cases, 11 patients had documented follow-up imaging ranging anywhere from 1 month to 7 years after the discovery of their metastatic seeding; two patients died within 14 months of detection of their metastatic seeding and the remaining nine patients continued to undergo imaging surveillance. One such patient was found to have four separate instances of recurrence, while the remaining eight patients were recurrence-free during their documented follow-up. As these cases demonstrate, close imaging surveillance is essential given the variability in recurrence intervals.

While the Society of Interventional Radiology does not currently have consensus guidelines for postablative surveillance of renal cell carcinoma,²¹ AUA guidelines recommend cross-sectional scanning (CT or MRI) with and without intravenous contrast at 3 and 6 months following ablative therapy to assess treatment success, followed by annual abdominal scans (CT or MRI) thereafter for 5 years.^{19 22} As our case illustrates, as well as other report cases in the literature, adherence to these surveillance recommendations is imperative as metastatic tract seeding may not present for several years after percutaneous intervention. Given the findings associated with our patient and others with reported tract seeding after percutaneous renal mass manipulation, it is critical that radiologists are aware of the risk of metastatic implantation and tailor their evaluation of the surrounding tissues for signs of this phenomenon.

To conclude, this case raises awareness of the risk of renal cell carcinoma seeding within the liver in instances of a transhepatic or juxtahepatic approach for percutaneous biopsy or ablation. Additionally, it demonstrates the possibility of successful percutaneous ablation for treatment of such metastatic implants. The radiologist should have constant awareness of the potential for metastatic implantation after percutaneous tumour manipulation in order to identify early recurrent disease and prompt potentially curative treatment.

Learning points.

• The risk of tract seeding postpercutaneous intervention, including visceral metastasis with a transhepatic approach, should be carefully considered by the performing provider and thoroughly discussed with the patient prior to intervention.

• Radiologists should include careful evaluation of percutaneous biopsy and ablation tracts in their search pattern when interpreting surveillance imaging after percutaneous intervention.

• While there is no multidisciplinary recommendation for interval surveillance of renal cell carcinoma after percutaneous ablation, healthcare providers should remain vigilant of the risk of recurrence and recommend appropriate surveillance intervals on a case-by-case basis.

• Metastatic seeding of a percutaneous access tract can be successfully treated with percutaneous ablation.

Ethics statements

Patient consent for publication

Consent obtained from next of kin.