Identification of signature gene set as highly accurate determination of metabolic dysfunction-associated steatotic liver disease progression.

BACKGROUND/AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by fat accumulation in the liver. MASLD encompasses both steatosis and MASH. Since MASH can lead to cirrhosis and liver cancer, steatosis and MASH must be distinguished during patient treatment. Here, we investigate the genomes, epigenomes, and transcriptomes of MASLD patients to identify signature gene set for more accurate tracking of MASLD progression. METHODS: Biopsy-tissue and blood samples from patients with 134 MASLD, comprising 60 steatosis and 74 MASH patients were performed omics analysis. SVM learning algorithm were used to calculate most predictive features. Linear regression was applied to find signature gene set that distinguish the stage of MASLD and to validate their application into independent cohort of MASLD. RESULTS: After performing WGS, WES, WGBS, and total RNA-seq on 134 biopsy samples from confirmed MASLD patients, we provided 1,955 MASLD-associated features, out of 3,176 somatic variant callings, 58 DMRs, and 1,393 DEGs that track MASLD progression. Then, we used a SVM learning algorithm to analyze the data and select the most predictive features. Using linear regression, we identified a signature gene set capable of differentiating the various stages of MASLD and verified it in different independent cohorts of MASLD and a liver cancer cohort. CONCLUSION: We identified a signature gene set (i.e., CAPG, HYAL3, WIPI1, TREM2, SPP1, and RNASE6) with strong potential as a panel of diagnostic genes of MASLD-associated disease.

A novel method to determine hepatic segments using Sonazoid, an ultrasound contrast agent.

The conventional radiologic method for liver segmentation is based on the position of the hepatic and portal veins. However, during surgery, liver segments are resected based on the distribution of hepatic portal blood flow. This discrepancy can lead to a number of problems, such as miscommunication among clinicians, missing the location of the segment with the hepatic mass, and the risk of extended hepatic resection. We suggest a novel method to determine hepatic segments based on portal blood flow, as in the surgical approach, but by using high and low mechanical indexes in contrast-enhanced ultrasonography with Sonazoid. This approach is helpful for preoperatively determining hepatic segments and reducing the risk of missing the location of a hepatic tumor or extended hepatic resection.

Gallstone, cholecystectomy and risk of gastric cancer.

BACKGROUNDS/AIMS: The aim of this retrospective study is to compare stomach cancer incidence, characteristics between gallstones, cholecystectomy and control groups. It also aims to investigate key variables' potential effects on overall survival. METHODS: A total of 99 patients, diagnosed with stomach cancers between April 1994 and December 2015, were identified. We excluded stomach cancer patients, accrued during the first year of follow-up in both the gallstones and cholecystectomy groups, assuming that they missed cancers. The main analyses addressing the objective were a chi-square analysis and a survival analysis. RESULTS: The incidence of stomach cancers was increased in both the gallstone and cholecystectomy groups, compared with the control group (p=0.003). Multivariate regression analysis showed that the overall survival in gallstones, cholecystectomy group patients as compared with those in the control group decreased (HR=6.66, 95 CI: 1.94-22.80, p=0.003). Also, T-stage was found to statistically affect the rate of overall survival (HR=9.85, 95% CI: 3.09-31.39, p=.000). The stomach cancer showed the worse survival at the posterior, greater curvature location than anterior, lesser curvature of the stomach. (HR=0.30, 95% CI: 0.11-0.80, p=0.017). CONCLUSIONS: We provided an awareness of the possible increased risks of stomach cancer in gallstone and cholecystectomy group patients, which might be induced by duodenogastric bile reflux. Also, the survival rate was poor (p<0.000). Therefore, close follow-up strategies for early detection are recommended for such patients.

Intraoperative radiofrequency ablation for hepatocellular carcinoma in 112 patients with cirrhosis: a surgeon's view.

PURPOSE: This retrospective study was an investigation of overall survival (OS), disease-free survival (DFS) and prognostic factors affecting OS and DFS in cirrhotic patients who received intraoperative radiofrequency ablation (IORFA). METHODS: Between April 2009 and November 2013, 112 patients (94 men, 84%; 18 women, 16%) underwent IORFA for 185 cases of hepatocellular carcinomas (HCC). Repeat IORFA was done in 9 patients during the same period (total of 121 treatments). RESULTS: All patients were followed-up for at least 12 months (mean follow-up, 32 months). Surgical resection combined with IORFA was performed in 20 patients. The technical effectiveness at 1 week was 91.78% (111 of 121). Readmission was 9.1% (11 of 121) and the most common cause was ventral hernia. Procedure-related mortality was 2.7% (3 of 112) and continued fatal biliary leakage was 1.8% (2 of 112). Local recurrence developed in 10 patients (8.9%). Most recurrence was intrahepatic. Cumulative survival was assessed in 33 patients who received IORFA as primary treatment (naive patients) and 79 non-naive patients. The cumulative DFS and OS rate at l and 3 years was 54% and 24%, and 87% and 66%, respectively. Moderate ascites (P = 0.001), tumor located segment I (P = 0.001), portal vein thrombosis (P = 0.001) had poor survival were significant factors by multivariate analysis. CONCLUSION: IORFA alone or in combination with surgical resection extends the spectrum of liver surgery. A fundamental understanding of RFA, additional comorbidities, and postablation complication are necessary to maximize the safety and efficacy of IORFA for treating HCC with cirrhosis.

Usefulness of acoustic radiation force impulse elastography in the differential diagnosis of benign and malignant solid pancreatic lesions.

PURPOSE: The aim of this study was to evaluate the tissue stiffness of solid pancreatic lesions by using acoustic radiation force impulse (ARFI) elastography to differentiate benign from malignant pancreatic lesions. METHODS: ARFI elastography was performed in 26 patients who had 27 focal solid pancreatic lesions, including 8 benign lesions (mass-forming pancreatitis, 5; autoimmune pancreatitis, 3) and 19 malignant lesions (pancreatic adenocarcinoma, 16; metastasis from colorectal cancer, 2; malignant neuroendocrine tumor, 1). On the elastographic images of virtual touch tissue imaging (VTI), the echogenicity of the mass was categorized on a 5-grade scale. On the elastographic image of virtual touch tissue quantification (VTQ), the shear wave velocities (SWVs) of the lesion and surrounding parenchyma were measured. RESULTS: On the VTI images, the mean echogenicity score of the malignant lesions (3.7±1.0) was higher than that of the benign lesions (3.1±0.4; P=0.023). On the VTQ images, there were no statistical differences in the mean SWV between the benign (2.4±1.1 m/sec) and malignant (3.3±1.0 m/sec) lesions (P=0.101). However, the mean SWV difference values between the lesion and background parenchyma of the malignant lesions (1.5±0.8 m/sec) were higher than those of the benign lesions (0.4±0.3 m/sec; P=0.011). CONCLUSION: ARFI elastography can determine the relative stiffness between a lesion and the background pancreatic parenchyma using VTI and VTQ, which is helpful in the differentiation between benign and malignant solid pancreatic lesions.

Focal thickening at the fundus of the gallbladder: computed tomography differentiation of fundal type adenomyomatosis and localized chronic cholecystitis.

BACKGROUND/AIMS: The objective of our study was to identify useful computed tomography (CT) findings for differentiating fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder. METHODS: We retrospectively identified cases of 41 patients with pathologically proven adenomyomatosis (n=21) or chronic cholecystitis (n=20) who had fundal thickening of the gallbladder on preoperative abdominal CT. Analysis of the CT findings included evaluation of the thickness, contour, border, intralesional cystic area, adjacent gallbladder wall thickening, presence of inner layer enhancement, enhancement grade, enhancement pattern, and presence of stones. Statistical analyses were performed using the Mann-Whitney U test and Fisher exact test. RESULTS: Oval contour, inner layer enhancement and intralesional cystic area were more frequently noted in adenomyomatosis than in chronic cholecystitis (p<0.05 for each finding). Flat contour and adjacent gallbladder wall thickening were more frequently observed in chronic cholecystitis than in adenomyomatosis. No differences between adenomyomatosis and chronic cholecystitis in terms of the thickness, enhancement grade, enhancement pattern and presence of stones were apparent. CONCLUSIONS: CT may help to differentiate fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder.

Epididymal lymphoma: report of two cases and imaging findings.

Epididymal lymphoma is a very rare tumor that is difficult to differentiate radiologically from other paratesticular tumors. Most cases of epididymal lymphoma are secondary involvement of the epididymis in patients with testicular lymphoma. However, isolated epididymal lymphoma is very rare. We herein report two cases of isolated epididymal lymphoma with different imaging findings. Patient 1 was a 52-year-old man who presented with a painless scrotal mass. Patient 2 was a 65-year-old man who presented with painless scrotal swelling. Ultrasound (US) demonstrated different imaging findings: US in patient 1 showed a well-defined round mass in the tail of the epididymis with hypervascularity confined to the epididymis, while US in patient 2 showed diffuse infiltrative enlargement with hypervascularity confined to the epididymis. Orchiectomy performed in both patients revealed diffuse large B-cell lymphoma confined to the epididymis.

Prognostic factors for gallbladder cancer in the laparoscopy era.

PURPOSE: Hepatobiliary surgery has changed dramatically in recent decades with the advent of laparoscopic techniques. The aim of this retrospective study was to compare survival rates according to stages, adjusting for important prognostic factors. METHODS: A retrospective study of a 17-year period from January 1994 to April 2011 was carried out. The cases studied were divided into two time period cohorts, those treated in the first 9-years (n = 109) and those treated in the last 7-years (n = 109). RESULTS: An operation with curative intent was performed on 218 patients. The 5-year survival rates according to the depth of invasion were 86% (T1), 56% (T2), 45% (T3), and 5% (T4). The number of cases of incidental gallbladder cancer found during 3,919 laparoscopic cholecystectomies was 96 (2.4%). Incidental gallbladder cancer revealed a better survival rate (P = 0.003). Iatrogenic bile spillage was found in 20 perforations of the gallbladder during laparoscopic cholecystectomies, 16 preoperative percutaneous transhepatic gallbladder drainages and 16 percutaneous transhepatic biliary drainages; only percutaneous transhepatic biliary drainage patients showed a significantly lower survival rate than patients without iatrogenic bile spillage (P < 0.034). Chemoradiation appeared to improve overall survival (P < 0.001). Multivariate analysis also revealed that time period, type of surgery, surgical margin, lymphovascular invasion, lymph node involvement, and chemoradiation therapy had significant effects. CONCLUSION: This study found that the prognosis of gallbladder cancer is still determined by the stage at presentation due to the aggressive biology of this tumor. Early diagnosis, radical resection and appropriate adjuvant therapy can increase overall survival.

Sodium iodide symporter and phosphatase and tensin homolog deleted on chromosome ten expression in cholangiocarcinoma analysis with clinicopathological parameters.

BACKGROUND/AIMS: This study was performed to investigate the correlation of sodium iodide symporter (NIS) expression with the functionality and loss of phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression in human cholangiocarcinoma (CCA). METHODS: Immunohistochemistry for the expression of NIS and PTEN was performed in 60 biopsy specimens of CCA. The clinicopathological parameters were retrospectively identified from medical records. The expression pattern of NIS and loss of PTEN expression were analyzed in association with the clinicopathological characteristics, including survival. RESULTS: Normal biliary trees displayed NIS expression, but hepatocytes did not. NIS expression was divided into two patterns: cytoplasmic and membranous. Fifty-nine cases, all except for one case, displayed NIS expression in tumor cells. Twenty-two cases (33.3%) were mixed pattern, and 39 cases (65.05%) were cytoplasmic pattern; the pure membranous pattern was not noted. There was no association between the NIS expression pattern and clinicopathological parameters, including age, sex, differentiation grade, T stage and tumor, node, metastasis stage (p>0.05). The survival rates were similar among various NIS expression patterns. Normal hepatocytes and biliary trees exhibited PTEN expression in the nucleus and cytoplasm. CCA cells displayed nuclear staining. Thirty-six (60.0%) of 60 cases displayed a loss of PTEN expression. The loss of PTEN expression was observed in the advanced T-stage group (p=0.0036), but there was no association between the loss of PTEN expression and other clinicopathological parameters (p>0.05). No association between the loss of PTEN expression and survival was noted. CONCLUSIONS: NIS is expressed in most types of human CCA. The expression pattern suggests a role in cancer development. PTEN loss expression is common in the context of human CCA, especially in the advanced T stage.

Efficacy of hepatic arterial infusion chemotherapy in advanced hepatocellular carcinoma.

AIM: To investigate the efficacy of hepatic arterial infusion chemotherapy (HAIC) using floxuridine (FUDR) in patients with advanced hepatocellular carcinoma (HCC) confined to the liver. METHODS: Thirty-four patients who had advanced HCC with unresectability or unsuccessful previous therapy in the absence of extrahepatic metastasis were treated with intra-arterial FUDR chemotherapy at our hospital between March 2005 and May 2008. Among the 34 patients, 9 patients were classified as Child class C, and 18 patients had portal vein tumor thrombus (PVTT). One course of chemotherapy consisted of continuous infusion of FUDR (0.3 mg/kg during day 1-14) and dexamethasone (10 mg on day 1, 4, 7 and 11), and this treatment was repeated every 28 d. RESULTS: Two patients (5.9%) displayed a complete response, and 12 patients (35.3%) had a partial response. The tumor control rate was 61.8%. The median overall survival times were 15.3 mo, 12.4 mo and 4.3 mo for the patients who were classified as Child class A, Child class B and Child class C, respectively (P = 0.0392). The progression-free survival was 12.9 mo, 7.7 mo and 2.6 mo for the patients who were classified as Child class A, Child class B and Child class C, respectively (P = 0.0443). The cumulative survival differed significantly according to the Child-Pugh classification and the presence of PVTT. In addition to hepatic reserve capacity and PVTT, the extent of HCC was an independent factor in determining a poor prognosis. The most common adverse reactions to HAIC were mucositis, diarrhea and peptic ulcer disease, but most of these complications were improved by medical treatment and/or a delay of HAIC. CONCLUSION: The present study demonstrates that intra-arterial FUDR chemotherapy is a safe and effective treatment for advanced HCC that is recalcitrant to other therapeutic modalities, even in patients with advanced cirrhosis.

A case of hepatic angiomyolipoma which was misdiagnosed as hepatocellular carcinoma in a hepatitis B carrier.

We report a rare case of resected hepatic AML, which was misdiagnosed as hepatocellular carcinoma in a chronic hepatitis B carrier. A 45-year-old woman who was a carrier of hepatitis B virus infection presented with a hepatic tumor. Her serum alpha-fetoprotein level was normal. Ultrasonography revealed a round and well-circumscribed echogenic hepatic tumor measuring 2.5 cm in the segment VI. On contrast-enhanced computed tomography, a hypervascular tumor was observed in the arterial phase and washing-out of the contrast medium in the portal phase and delayed phase. On MR T1-weighted in-phase images, the mass showed low signal intensity, and on out-of-phase images, the mass showed signal drop and dark signal intensity. On MR T2-weighted images, the mass showed high signal intensity. The mass demonstrated high signal intensity on arterial phase after contrast injection, suggestive of hepatocellular carcinoma. The patient underwent hepatic wedge resection and histopathological diagnosis was a hepatic angiomyolipoma.

Lessons learned from 100 initial cases of laparoscopic liver surgery.

PURPOSE: Laparoscopic liver resection (LLR) is now widely accepted and is being increasingly performed. The present study describes our experience with LLR at a single center over an eight-year period. METHODS: This retrospective study enrolled 100 patients between October 2002 and February 2010. Forty-six benign lesions and 54 malignant lesions were included. The LLR performed included 58 pure laparoscopy procedures, 18 hand-assisted laparoscopy procedures and 24 hybrid technique procedures. RESULTS: The mean age of the patients was 57 years; among these patients, 31 were over 65 years of age. The mean operation time was 220 minutes. The overall morbidity was 11% and the mortality was zero. Among the 20 patients with simple hepatic cysts, 50% unexpectedly recurred. Among the 41 patients with hepatocellular carcinoma, 21 patients (51%) underwent preoperative radiofrequency ablation therapy or transarterial chemoembolization. During parenchymal-transection, 11 received blood transfusion. The width of the resection margins was under 0.5 cm in 11 cases (27%); 0.5 to 1 cm in 22 cases (54%) and over 1 cm in eight cases (12%). There was no port site seeding, but argon beam coagulation-induced tumor dissemination was observed in two cases. The overall two-year survival rate was 75%. CONCLUSION: This study suggests that the applications for LLR can be gradually expanded when assuring that the safety and curability of LLR are equivalent to that of open liver resection.

Acoustic radiation force impulse elastography for hepatocellular carcinoma-associated radiofrequency ablation.

AIM: To evaluate the potential usefulness of acoustic radiation force impulse (ARFI) images for evaluation of hepatocellular carcinomas (HCC)-associated radiofrequency ablation. METHODS: From January 2010 to June 2010, a total of 38 patients with HCC including recurred HCCs after RFA underwent ARFI elastography. The brightness of tumor was checked and the shear wave velocity was measured for the quantification of stiffness. According to the brightness, the tumors were classified as brighter, same color and darker compared with adjacent parenchyma. Using the same methods, 8 patients with recurred HCCs after RFA state were evaluated about the brightness compared with adjacent RFA ablation area. RESULTS: In the 38 patients with HCCs, 20 (52.6%) were brighter than surrounding cirrhotic parenchyma. Another 13 (34.2%) were darker. The others (5 cases, 13.2%) were seen as the same color as the adjacent liver parenchyma. Post-RFA lesions were darker than previous tumor and surrounding parenchyma in all 38 cases. However, recurred HCCs were brighter than the treated site in all 8 cases. CONCLUSION: Using ARFI technique is helpful for differential diagnosis in order to detect recurred HCCs more easily in patients with confusing status.

Splenic infarction associated with sorafenib use in a hepatocellular carcinoma patient.

Sorafenib, a multitargeted tyrosine kinase inhibitor, has been shown to improve survival in patients with advanced hepatocellular carcinoma (HCC). As the clinical use of sorafenib increases, many adverse effects have been reported, such as hand-foot skin reaction, diarrhea, anorexia, asthenia, alopecia, weight loss, hypertension and arterial thromboembolism. However, there are no prior reports of splenic infarction as an adverse effect of sorafenib. Here, a case of splenic infarction in a patient with HCC who was treated with sorafenib is reported. The patient had no other predisposing factors to explain the splenic infarction except for the administration of sorafenib. The splenic infarction improved after sorafenib was discontinued; however, the HCC progressed.

Recurrent hepatic alveolar echinococcosis: report of the first case in Korea with unproven infection route.

Human alveolar echinococcosis (AE), a hepatic disorder that resembles liver cancer, is a highly aggressive and lethal zoonotic infection caused by the larval stage of the fox tapeworm, Echinococcus multilocularis. E. multilocularis is widely distributed in the northern hemisphere; the disease-endemic area stretches from north America through Europe to central and east Asia, including northern parts of Japan, but it has not been reported in Korea. Herein, we represent a first case of AE in Korea. A 41-year-old woman was found to have a large liver mass on routine medical examination. The excised mass showed multinodular, necrotic, and spongiform appearance with small irregular pseudocystic spaces. Microscopically, the mass was composed of chronic granulomatous inflammation with extensive coagulation necrosis and parasite-like structure, which was revealed as parasitic vesicles and laminated layer delineated by periodic acid-Schiff (PAS) stain. Clinical and histologic features were consistent with AE. After 8 years, a new liver mass and multiple metastatic pulmonary nodules were found and the recurred mass showed similar histologic features to the initial mass. She had never visited endemic areas of AE, and thus the exact infection route is unclear.

Actinomycosis of the appendix mimicking appendiceal tumor: a case report.

Actinomycosis is an uncommon chronic infectious disease. Common sites of involvement include the cervicofacial, thoracic and abdominopelvic regions. In abdominopelvic actinomycosis, the ileocecal region, including the appendix, is the most commonly involved site. In some reports, limited appendiceal actinomycosis has revealed a thickened appendiceal wall with peri-appendiceal inflammation as acute appendicitis or perforated appendicitis. We experienced pathologically confirmed intraluminal limited appendiceal actinomycosis without peri-appendiceal infiltration. Here, we report the computed tomography and ultrasound findings.

Radiofrequency ablation of renal VX2 tumors with and without renal artery occlusion in a rabbit model: feasibility, therapeutic efficacy, and safety.

The purpose of this study was to determine the therapeutic efficacy of radiofrequency ablation for treating renal VX2 tumors with and without renal artery occlusion in a rabbit model. Twenty-four New Zealand White rabbits were percutaneously implanted with renal VX2 tumors. Fifteen days after implantation, both kidneys were surgically exposed, and radiofrequency ablation was conducted. Group A (n=12) was treated with renal artery occlusion, and group B (n=12) was treated without occlusion. In each rabbit, the serum creatinine was measured to evaluate renal damage after arterial occlusion. Two days after radiofrequency ablation, computed tomography was performed to evaluate the difference in therapeutic results between the two groups. We also compared histopathologic findings after radiofrequency ablation. The mean tumor size was 2.4 cm (range, 1.2-3.1 cm). Radiofrequency ablation of renal tumors was technically feasible in all cases. Complete ablation was achieved in 11 of the 12 rabbits (92%) in group A but in only eight of the 12 rabbits (67%) in group B (P<0.05). The average time of radiofrequency application was shorter in group A (mean, 547 s) than in group B (mean, 826 s) (P<0.05). After radiofrequency ablation, the serum creatinine increased from 1.54 to 1.82 mg/dl in group A and from 1.46 to 1.78 mg/dl in group B. However, there was no significant difference between the two groups (P>0.05). In conclusion, radiofrequency ablation with renal artery occlusion can decrease the duration of treatment and increase the therapeutic efficacy for renal VX2 tumors.

Discrete hypoechoic ring in hepatic cavernous hemangioma resembling a malignant tumor: correlation with histologic features.

Differential diagnoses of hepatic nodules include hepatocellular carcinoma, focal nodular hyperplasia, hepatic adenoma, regenerative nodule, focal fatty changes, and hemangioma. However, differentiation of these nodules can often be difficult. Hemangiomas are frequently encountered during ultrasonogram incidentally and can be diagnosed easily because they have an almost distinctive sonographic appearance: a homogeneous hyperechogenicity and discrete posterior acoustic enhancement. They also sometimes have atypical findings, for example an internal echogenicity including hypoechogenicity, heterogeneous echogenicity, hyperechoic rim, central hypoechogenicity due to various changes (e.g., internal hemorrhage, necrosis, thrombosis, myxomatous change, and fibrosis), and (rarely) calcification. We report herein the case of an atypical hemangioma presenting with a hypoechoic peripheral ring, mimicking a hepatic malignancy. To our knowledge, there have been no other reports demonstrating a cavernous hemangioma with a discrete hypoechoic ring and without a pseudocapsule.

Gastrointestinal amyloidosis presenting with multiple episodes of gastrointestinal bleeding.

Amyloidosis is characterized by the extracellular deposition of amyloid protein in various organs. Gastrointestinal involvement in amyloidosis is common, but a diagnosis of amyloidosis is often delayed. Severe gastrointestinal hemorrhage in amyloidosis is rare but can be fatal in some cases. We experienced a case of a 49-year-old man who presented with recurrent massive hematochezia. Although embolization was performed eight times for bleeding from different sites of the small intestine, hematochezia did not cease. We report the case, with a review of the literature.

Radiofrequency ablation treatment for renal cell carcinoma: early clinical experience.

OBJECTIVE: To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43-73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow-up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. RESULTS: All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1-5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17-33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). CONCLUSION: The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.