KIDNEY-PAGER: analysis of circulating tumor DNA as a biomarker in renal cancer - an observational trial. Study protocol.

BACKGROUND: Management of localized renal cell carcinoma (RCC) is challenged by inaccurate methods to assess the risk of recurrence and deferred detection of relapse and residual disease after radical or partial nephrectomy. Circulating tumor DNA (ctDNA) has been proposed as a potential biomarker in RCC. PURPOSE: Conduction of an observational study to evaluate the validity of ctDNA as a biomarker of the risk of recurrence and subclinical residual disease to improve postoperative surveillance. MATERIAL AND METHODS: Urine and blood will be prospectively collected before and after surgery of the primary tumor from up to 500 patients until 5 years of follow-up. ctDNA analysis will be performed using shallow whole genome sequencing and cell-free methylated DNA immunoprecipitation sequencing. ctDNA levels in plasma and urine will be correlated to oncological outcomes. Residual blood and urine as well as tissue biopsies will be biobanked for future research. INTERPRETATION: Results will pave the way for future ctDNA-guided clinical trials aiming to improve RCC management.

The changing trends of image-guided biopsy of small renal masses before intervention-an analysis of European multinational prospective EuRECA registry.

OBJECTIVES: To evaluate the use of pre-cryoablation biopsy for small renal masses (SRMs) and the effects of increasing uptake on histological results of treated SRMs. METHODS: From 2015 to 2019, patients with sporadic T1N0M0 SRMs undergoing percutaneous, laparoscopic, or open cryoablation from 14 European institutions within the European Registry for Renal Cryoablation (EuRECA) were included for the retrospective analysis. Univariate and multivariate logistic models were used to evaluate the trends, histological results, and the factors influencing use of pre-cryoablation biopsy. RESULTS: In total, 871 patients (median (IQR) age, 69 (14), 298 women) undergoing cryoablation were evaluated. The use of pre-cryoablation biopsy has significantly increased from 42% (65/156) in 2015 to 72% (88/122) in 2019 (p < 0.001). Patients treated for a benign histology are significantly more likely to have presented later in the trend, where pre-cryoablation biopsy is more prevalent (OR: 0.64, 95% CI 0.51-0.81, p < 0.001). Patients treated for undiagnosed histology are also significantly less likely to have presented in 2018 compared to 2016 (OR 0.31, 95% CI 0.10-0.97, p = 0.044). Patients aged 70+ are less likely to be biopsies pre-cryoablation (p < 0.05). R.E.N.A.L. nephrometry score of 10+ and a Charlson Comorbidity Index > 1 are factors associated with lower likelihood to not have received a pre-cryoablation biopsy (p < 0.05). CONCLUSION: An increased use of pre-cryoablation biopsy was observed and cryoablation patients treated with a benign histology are more likely to have presented in periods where pre-cryoablation biopsy is not as prevalent. Comparative studies are needed to draw definitive conclusions on the effect of pre-cryoablation biopsy on SRM treatments. KEY POINTS: • The use of biopsy pre-ablation session has increased significantly from 42% of all patients in 2015 to 74% in 2019. • Patients are less likely to be treated for a benign tumour if they presented later in the trend, where pre-cryoablation biopsy is more prevalent, compared to later in the trend (OR 0.64, 95% CI 0.51-0.81, p < 0.001). • Patients with comorbidities or a complex tumour (R.E.N.A.L. nephrometry score > 10) are less likely to not undergo biopsy as a separate session to cryoablation.

Renal cryoablation: Multidisciplinary, collaborative and perspective approach.

Renal cryoablation is becoming an established treatment option for small renal masses. It allows preservation of renal function without compromising cancer control. The technique has evolved considerably since it was first reported using liquid nitrogen over 20 years ago. We describe the modern technique for both laparoscopic and image guided renal cryoablation. Renal cryoablation is performed either laparoscopically or percutaneously depending on tumour characteristics. Common features include biopsy of the mass, protection of adjacent organs, and the use of compressed argon gas for freezing and helium for thawing. Dynamic monitoring is used to ensure adequate treatment. The shape of the iceball can be modified by adding extra needles or changing their positions. A double freeze/thaw is necessary for confident ablation of all cancer cells. The laparoscopic approach includes exposure of the tumour and may involve extensive mobilisation of the kidney. Laparoscopic ultrasound is essential for correct localisation of the tumour, needle placement, and monitoring the treatment. A Temperature probe is placed at the edge of the tumour to record treatment temperature. The percutaneous approach is typically performed with CT guidance. Adjacent organs can be protected by injecting saline or carbon dioxide. Early imaging is helpful to detect or rule out incomplete treatment. Post-operative follow-up is structured at specific intervals (e.g. 3, 6, 12 months then annually) and perhaps tailored or modified based on the degree of suspicion of inadequate treatment.

Short-term complications for percutaneous ultrasound-guided biopsy of renal masses in adult outpatients.

Background Ultrasound-guided percutaneous kidney tumor biopsy (UGPKB) plays an important role in the diagnosis of renal tumor but there are no consensuses with respect to the length and the extend of the post-biopsy observation period. Purpose To assess the short-term complication rate after UGPKB and to evaluate whether the onset of complications allows for the procedure to be performed in an outpatient setting with same-day discharge. Material and Methods Between March 2012 and March 2014, a total of 287 UGPKB were performed in an outpatient setting at a Danish university referral center. All patient records were retrospectively reviewed and post-biopsy complications as well as biochemical parameters were registered. Results The overall complication rate was 3.8% (11 patients). Major complications occurred in 1.0% of all cases (three patients); one patient with ongoing bleeding that required intervention and two patients with septicemia. Minor complications occurred in 2.8% of cases (eight patients); six patients with self-limiting gross hematuria, one patient with small asymptomatic subcapsular hematoma, and one patient with vasovagal syncope. The timing of both minor and major complication onset ranged from the time of biopsy and up to four days after discharge. Conclusion UGPKB of indeterminate renal masses in adult patients in an outpatient setting appears to be a safe procedure with a very low rate of major complications. Same-day discharge after renal mass biopsy seems feasible.

Efficacy of commercialised extracorporeal shock wave lithotripsy service: a review of 589 renal stones.

BACKGROUND: Extracorporeal shockwave lithotripsy (ESWL) is the management of choice for renal stones 20 mm or smaller, with a stone clearance rate of up to 89%. The purpose of the present is to investigate the efficacy of a commercialised ESWL service, being performed as an outsourced treatment using a mobile lithotripsy system on an outpatient basis. Furthermore, the study aims to evaluate the risk of needing treatment with an internal ureteral double-J stent (JJ) after ESWL treatment. METHODS: During an eight-year period, 461 patients with a total of 589 renal stones were treated using a mobile lithotripsy system at a single Danish institution. A commercial company performed all treatments using a Storz Modulith SLK® system. Each stone was prospectively registered according to size, intra renal location and the presence of a JJ at the time of treatment. The number of required ESWL treatments and auxiliary procedures were retrospectively evaluated. RESULTS: The success rate after the initial ESWL procedure was 69%, which increased to an overall success rate of 93% after repeated treatment. A negative correlation was found between stone size and the overall success rate (r = -0.2, p < 0.01). The upper calyx was associated with a significantly better success rate, but otherwise intra renal stone location was not predictive for treatment success. A total of 17 patients (2.9%) required treatment with a JJ after the ESWL procedure. No significant difference was observed between the stone size or intra renal location and the risk of needing treatment with JJ after ESWL. CONCLUSIONS: Commercialised ESWL treatment can achieve an overall success rate of more than 90% using a mobile lithotripsy system. As expected, an inverse relation between stone size and success rate was found. Patients who do not require treatment with a JJ prior to ESWL will only rarely need treatment with a JJ after ESWL, irrespective of stone size and intra renal stone location.

Management of Renal Cell Carcinoma: Promising Biomarkers and the Challenges to Reach the Clinic.

The incidence of renal cell carcinoma (RCC) is increasing worldwide, yet research within this field is lagging behind other cancers. Despite increased detection of early disease as a consequence of the widespread use of diagnostic CT scans, 25% of patients have disseminated disease at diagnosis. Similarly, around 25% progress to metastatic disease following curatively intended surgery. Surgery is the cornerstone in the treatment of RCC; however, when the disease is disseminated, immunotherapy or immunotherapy in combination with a tyrosine kinase inhibitor is the patient's best option. Immunotherapy is a potent treatment, with durable treatment responses and potential to cure the patient, but only half of the patients benefit from the administered treatment, and there are currently no methods that can identify which patients will respond to immunotherapy. Moreover, there is a need to identify the patients in greatest risk of relapsing after surgery for localized disease and direct adjuvant treatment there. Even though several molecular biomarkers have been published to date, we are still lacking routinely used biomarkers to guide optimal clinical management. The purpose of this review is to highlight some of the most promising biomarkers, discuss the efforts made within this field to date, and describe the barriers needed to be overcome to have reliable and robust predictive and prognostic biomarkers in the clinic for renal cancer.

Active Surveillance of Small Renal Masses in a Large Danish Cohort: Assessing Proficiency in Patient Selection.

Small renal masses (SRMs) are often benign or early-stage cancers with low metastatic potential. The risk of overtreating SRMs is a particular concern in elderly or comorbid patients, for whom the risks associated with active surveillance (AS) are lower than the risks of surgical management. The aim is to systematically analyse a large cohort of AS patients to provide valuable insights into patient selection and outcomes concerning delayed intervention (DI) and AS termination. We retrospectively analysed data from 563 AS patients across three institutions from 2012 to 2023. Patients were classified into three groups: those currently in AS (n=283), those who underwent DI (n=75), and those who terminated AS (n=205). DI patients were younger, and had larger initial tumour size and higher growth rates (GRs) than AS patients. A significant number of patients terminated their AS, mainly due to comorbidities and death from non-kidney cancer causes, suggesting unsuitability for initial AS enrolment. AS appears to be a safe initial management strategy for SRMs, with an overall low GR and only one patient developing metastasis. The patient selection for AS appears inconsistent, highlighting the need for improved criteria to identify AS candidates, especially considering comorbidities and the possibility of subsequent active treatment in the event of progression.

Pulmonary embolisms and infections after renal trauma.

INTRODUCTION: The objective of this study was to describe and evaluate the management of patients with renal trauma and their complications at the Department of Urology at Aarhus University Hospital (AUH), Denmark. METHODS: All patients diagnosed with renal injury due to trauma and with contact to the Department of Urology at the AUH, Denmark, between March 2016 and March 2021 were included. Patients were identified by the International Classification of Diseases, Tenth version, code and data obtained from electronic patient records. RESULTS: A total of 58 patients were identified. The median age was 33 years (7-95 years) and the median length of hospitalisation was five days (range: 0-52 days). All patients were evaluated with a multiphase computed tomography upon admission. Injuries to the kidney were graded using the American Association for the Surgery of Trauma kidney injury scale. Twelve percent had grade I injury, 26% had grade II injury, 26% had grade III injury, 36% had grade IV injury and 3% had grade V injury. In the acute phase, all patients were managed non-operatively. Early complications were found in 24% of patients. Pulmonary embolism was diagnosed in 7%. Furthermore, 7% had an infection as a late complication and all of these patients had also had an early infection. A total of 60% were followed up with a renal-scintigraphy three months after their renal trauma. This examination had no consequence for any of the patients. CONCLUSIONS: No patients died due to the renal trauma. However, many experienced complications in terms of infections and pulmonary embolisms. These data support earlier findings and suggest that a renal scintigraphy after renal traumas may be obsolete. FUNDING: None. TRIAL REGISTRATION: Not relevant.

Multiparametric magnetic resonance imaging for characterizing renal tumors: A validation study of the algorithm presented by Cornelis et al.

Objectives: In the last decade, the incidence of renal cell carcinoma (RCC) has been rising, with the greatest increase observed for solid tumors. Magnetic resonance imaging (MRI) protocols and algorithms have recently been available for classifying RCC subtypes and benign subtypes. The objective of this study was to prospectively validate the MRI algorithm presented by Cornelis et al. for RCC classification. Material and Methods: Over a 7-month period, 38 patients with 44 renal tumors were prospectively included in the study and received an MRI examination in addition to the conventional investigation program. The MRI sequences were: T2-weighted, dual chemical shift MRI, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced T1-weighted in wash-in and wash-out phases. The images were evaluated according to the algorithm by two experienced, blinded radiologists, and the histopathological diagnosis served as the gold standard. Results: Of 44 tumors in 38 patients, only 8 tumors (18.2%) received the same MRI diagnosis according to the algorithm as the histopathological diagnosis. MRI diagnosed 16 angiomyolipoma, 14 clear cell RCC (ccRCC), 12 chromophobe RCC (chRCC), and two papillary RCC (pRCC), while histopathological examination diagnosed 24 ccRCC, four pRCC, one chRCC, and one mixed tumor of both pRCC and chRCC. Malignant tumors were statistically significantly larger than the benign (3.16 ± 1.34 cm vs. 2.00 ± 1.04 cm, P = 0.006). Conclusion: This prospective study could not reproduce Cornelis et al.'s results and does not support differentiating renal masses using multiparametric MRI without percutaneous biopsy in the future. The MRI algorithm showed few promising results to categorize renal tumors, indicating histopathology for clinical decisions and follow-up regimes of renal masses are still required.

Oncological and Peri-Operative Outcomes of Percutaneous Cryoablation of Renal Cell Carcinoma for Patients with Hereditary RCC Diseases-An Analysis of European Multi-Centre Prospective EuRECA Registry.

This study aims to evaluate the safety, efficacy, and renal function preservation of percutaneous cryoablation (PCA) for small renal masses (SRMs) in inherited RCC syndromes. Patients with inherited T1N0M0 RCCs (<7 cm) undergoing PCA from 2015 to 2021 were identified from the European Registry for Renal Cryoablation (EuRECA). The primary outcome was local recurrence-free survival (LRFS). The secondary outcomes included technical success, peri-operative outcomes, and other oncological outcomes estimated using the Kaplan-Meier method. Simple proportions, chi-squared tests, and t-tests were used to analyse the peri-operative outcomes. A total of 68 sessions of PCA were performed in 53 patients with RCC and 85 tumours were followed-up for a mean duration of 30.4 months (SD ± 22.0). The overall technical success rate was 99%. The major post-operative complication rate was 1.7%. In total, 7.4% (2/27) of patients had >25% reduction in renal function. All oncological events were observed in VHL patients. Estimated 5-year LRFS, metastasis-free survival, cancer-specific survival, and overall survival were 96.0% (95% CI 75-99%), 96.4% (95% CI 77-99%), 90.9% (95% CI 51-99%), and 90.9% (95% CI 51-99%), respectively. PCA of RCCs for patients with hereditary RCC SRMs appears to be safe, offers low complication rates, preserves renal function, and achieves good oncological outcomes.

Gangrene of the Kidney Following Percutaneous Renal Cryoablation of a Small Tumor.

Background: In selected cases cryoablation is a valid treatment option for small renal masses. The procedure is generally considered oncologically efficient with a low rate of severe complications. We report here a case of a 62-year-old man who after percutaneous cryoablation develops severe gangrene in the treated kidney. Case Presentation: A 62-year-old man was incidentally diagnosed with a 45-mm renal cell carcinoma. The tumor was found on a CT scan performed on the suspicion of diverticulitis. An abscess in relation to the sigmoid was found and he was treated with aspiration and antibiotics. The tumor was treated with percutaneous cryoablation 20 days later. On the third postoperative day, he was readmitted with urosepsis. A CT scan revealed gangrene at the ablation site, and a nephrectomy was performed. Clinical progress was slow, and a new CT scan showed reformation of the abscess at the sigmoid and a suspicion of a colonic tumor was raised. This was confirmed by coloscopy and biopsy. The patient had a right hemicolectomy, and the pathology report described a T4 adenocarcinoma with positive margins. After 4 months follow-up, metastases to the lungs was found and the patient was referred to further oncologic treatment. Conclusion: Renal cryoablation is generally a very safe procedure, but severe complications may occur. This case report highlights that attention should be given to recent abdominal infections and that delayed intervention might be in place in selected cases.

Renal cryoablation: five- and 10-year survival outcomes in patients with biopsy-proven renal cell carcinoma.

OBJECTIVE: To investigate the long-term oncological efficacy of renal cryoablation (CA) of small renal tumors. MATERIALS AND METHODS: A review of patients treated with CA for a biopsy confirmed renal cell carcinoma less than 4 cm in diameter. All patients were identified from a prospectively maintained clinical database. Treatment efficacy was computed using the Kaplan-Meier method to estimate disease-free survival (DFS) and overall survival rates (OS). RESULTS: A total of 179 patients (116 men and 63 women) with a mean age of 64 years (95% CI = 63 - 66) were included in the analysis. Mean tumor size was 27 mm (95% CI = 25.5-28.0) with a low, moderate and high PADUA complexity score in 30.2%, 44.7% and 16.2% of the cases, respectively. A total of 19 patients (11%) were diagnosed with residual unablated tumor, six patients (3%) were diagnosed with late local recurrence and six patients (3%) were diagnosed with metastatic disease. The estimated 5 years image confirmed the DFS rate was 79% (95% CI = 70-85). The estimated 5- and 10-year OS rates were 82% (95% CI = 75-87) and 61% (95% CI = 48-71), respectively. During the 10-year follow-up period a total of five patients (3%) died due to renal cancer, while 46 patients (26%) died from other causes. CONCLUSIONS: CA appears to be an effective treatment modality for patients with small renal tumors. The present study demonstrated low rates of local recurrence and disease progression with excellent long-term cancer-specific survival.

Renal cryoablation - does deep endophytic ablation affect the renal collecting system?

Objective: To investigate to what extent the urothelium of the renal collecting system is affected when performing deep endophytic cryoablation.Methods: The study was conducted as an in vivo animal model with a total of 15 female pigs. Each animal was subjected to bilateral endophytioc renal cryoablation and randomized to a postoperative follow-up period of either one, two or four weeks. At the end of follow-up all animals had a magnetic resonance imaging (MRI) examination and bilateral nephrectomy was performed. On MRI-imaging the extent of the cryolesions, as well as signs of urinomas or fistulas, were examined. Histopathologic examinations were performed to investigate the effect on the urothelium.Results: All animals tolerated the procedure well without any postoperative complications. MRI examinations found the renal collecting system to be involved in the cryolesions at all three stages of follow-up and revealed no signs of hematomas, urinomas or fistula formations. Epithelial edema was found at all three stages of follow-up while significant parenchymal fibrosis adjacent to the urothelium was most pronounced in the four weeks of follow-up group. The urothelium was significantly affected with luminal hemorrhage as well as hemorrhage in and underneath the urothelium and urothelial dissociation from the underlying renal parenchyma. Despite these impacts on the urothelium, this was found to be intact and vital at all three stages of follow-up, in sharp contrast to the renal parenchyma that underwent fibrotic changes.Conclusions: In this, in vivo non-tumor pig model CA effectively destroyed the renal parenchyma while the impacted renal urothelium remained intact and did not undergo fibrotic changes, nor was urinomas or fistulas observed.

Repeated Cryoablation as Treatment Modality After Failure of Primary Renal Cryoablation: A European Registry for Renal Cryoablation Multinational Analysis.

Objectives: To assess the oncological outcome of recryoablation following failure of primary cryoablation in patients with small renal masses (SRMs). Materials and Methods: A retrospective review of 72 patients with a single renal tumor who failed primary laparoscopy-assisted cryoablation (LCA). All patients were initially treated with LCA at one of three European centers during a 12-year period. Results: A total of 38 patients (53%) were successfully salvaged with reablation(s) following treatment failure after primary LCA, having a median follow-up time of 28 (95% CI 19-105) months. Patients who failed recryoablation with additional cryoablation (n = 11), active surveillance (n = 11), oncological treatment (n = 7), partial nephrectomy/nephrectomy (n = 5), and follow-up terminated according to patient request (n = 4). The disease-free survival was significantly higher for patients retreated with CT-guided cryoablation compared with other cryoablative modalities (57% vs 31%, p = 0.046). Conclusion: Recryoablation following failure of primary cryoablation appears to have a significantly lower success rate compared with what is well known from primary cryoablation of SRM, but does not carry and increase risk of metastatic progression. CT-guided recryoablation appears to be superior to laparoscopy-assisted or ultrasonography recryoablation.

Laparoscopic vs Percutaneous Cryotherapy for Renal Tumors: A Systematic Review and Meta-Analysis.

BACKGROUND: Cryoablation has emerged as an alternative to the more invasive partial nephrectomy for small renal masses. The approach can be carried out by two techniques, either laparoscopic cryoablation (LCA) or percutaneous cryoablation, (PCA) with CT guidance. We aimed to compare between the two procedures. MATERIALS AND METHODS: A systematic review and meta-analysis was conducted, including studies comparing the two techniques. Outcomes included incomplete ablation, late local recurrence, cancer-specific survival, procedure time, transfusion rates, hospital stay, and complications. RESULTS: A total of 1475 patients were included, 788 patients in the laparoscopic group and 687 patients in the percutaneous group. There was statistical difference favoring the laparoscopic group with regard to having less incomplete ablation (p = 0.0008) and higher cancer-specific survival patients (p = 0.04). However, there was longer hospital stays in the LCA group (p < 0.00001) and was found to be more costly than the PCA group. There was significantly more Clavien-I complications in the PCA group (p = 0.001) and more Clavien-III complications in the LCA group (p = 0.001). Otherwise, there were no differences in any other outcome parameter. CONCLUSION: LCA was found to have less incomplete tumor ablation rates and higher cancer-specific survival rates, however, higher hospitalization time, more major complications (Clavien III), and was costlier compared with PCA.

Cryoablation of Renal Angiomyolipoma: An Evaluation of Safety and Efficacy.

BACKGROUND: Small series have reported that cryoablation (CA) is a safe and feasible minimally invasive nephron-sparing alternative for the treatment of renal angiomyolipomas (renal AMLs). The aim of the present study was to investigate the safety and efficacy of CA in patients with renal AML. MATERIALS AND METHODS: A retrospective review of 19 renal AML lesions treated with CA at Aarhus University Hospital, Denmark, over a 5-year period. RESULTS: The treatment was performed as laparoscopy-assisted CA on 7 lesions, and in the remaining 12 lesions CA was performed as a percutaneous ultrasound-guided CA. The mean patient age was 46 years [interquartile range (IQR) 30] and the mean tumor volume was 50.1 cm3 (IQR 53.3). In all cases, the procedure was effectively conducted with no conversion to open surgery, and no major complications were experienced. The mean follow-up time was 25 months (IQR 13). Mean maximum tumor volume was reduced from 50.1 cm3 (IQR 53.3) to 12.2 cm3 (IQR 14.1), p = 0.05. No patients presented with retroperitoneal hemorrhage or recurrence during follow-up. CONCLUSION: Treating renal AMLs with CA appears to be a safe and effective nephron-sparing approach and could be a valuable alternative to other treatment modalities. The low complication rate, absence of retreatment and a good preservation of renal function might allow treatment of even subclinical renal AMLs to minimize the risk of potentially life-threatening hemorrhage.

Computed Tomography Perfusion, Magnetic Resonance Imaging, and Histopathological Findings After Laparoscopic Renal Cryoablation: An In Vivo Pig Model.

The present study investigates how computed tomography perfusion scans and magnetic resonance imaging correlates with the histopathological alterations in renal tissue after cryoablation. A total of 15 pigs were subjected to laparoscopic-assisted cryoablation on both kidneys. After intervention, each animal was randomized to a postoperative follow-up period of 1, 2, or 4 weeks, after which computed tomography perfusion and magnetic resonance imaging scans were performed. Immediately after imaging, open bilateral nephrectomy was performed allowing for histopathological examination of the cryolesions. On computed tomography perfusion and magnetic resonance imaging examinations, rim enhancement was observed in the transition zone of the cryolesion 1week after laparoscopic-assisted cryoablation. This rim enhancement was found to subside after 2 and 4 weeks of follow-up, which was consistent with the microscopic examinations revealing of fibrotic scar tissue formation in the peripheral zone of the cryolesion. On T2 magnetic resonance imaging sequences, a thin hypointense rim surrounded the cryolesion, separating it from the adjacent renal parenchyma. Microscopic examinations revealed hemorrhage and later hemosiderin located in the peripheral zone. No nodular or diffuse contrast enhancement was found in the central zone of the cryolesions at any follow-up stage on neither computed tomography perfusion nor magnetic resonance imaging. On microscopic examinations, the central zone was found to consist of coagulative necrosis 1 week after laparoscopic-assisted cryoablation, which was partially replaced by fibrotic scar tissue 4 weeks following laparoscopic-assisted cryoablation. Both computed tomography perfusion and magnetic resonance imaging found the renal collecting system to be involved at all 3 stages of follow-up, but on microscopic examination, the urothelium was found to be intact in all cases. In conclusion, cryoablation effectively destroyed renal parenchyma, leaving the urothelium intact. Both computed tomography perfusion and magnetic resonance imaging reflect the microscopic findings but with some differences, especially regarding the peripheral zone. Magnetic resonance imaging seems an attractive modality for early postoperative follow-up.

[Foreign objects in the urethra].

Foreign objects in the urethra are rare. Most cases are often caused by self-mutilating behaviour, in which the patient inserts an object into the urethra. Usually this is performed in a sexual context, and many different objects have been used. This case report presents a patient who used a 4 cm bullet-looking metal object for sexual pleasure. Cystoscopy revealed an object deep in the urethra, penetrating through the urethral mucosa. The object was removed endoscopically. At follow-up the patient experienced no sequelae, although infections, urethral stricture or fistula may occur in these cases.

Acute renal failure and arterial hypertension due to subcapsular haematoma: is percutaneous drainage a feasible treatment?

Percutaneous drainage proved to be successful in managing a renal subcapsular haematoma that was causing acute renal failure and hypertension in a 74-year-old woman. The patient presented with oliguria, nausea and malaise 2 days after a ureteronephroscopic procedure with biopsies of a suspected urothelial neoplasm in the right renal pelvis. The left kidney had recently been removed due to renal cell carcinoma. At admission, the patient's blood pressure and plasma creatinine levels were massively elevated. Ultrasonography revealed a moderate right-sided renal subcapsular haematoma. When the patient did not respond to antihypertensive treatment, Page kidney was suspected. A pigtail catheter was placed in the haematoma and, shortly after drainage, the diuresis resumed and plasma creatinine together with blood pressure decreased. This condition had previously been managed by open surgery, but recent case reports have described successful management by laparoscopy-assisted and radiology-assisted drainage, as described in this case report.

Laparoscopic cryoablation of angiomyolipomas in adolescents and young adults: A report of four cases associated with tuberous sclerosis and 1 case of sporadic origin.

INTRODUCTION: Renal angiomyolipomas (AMLs) can be of sporadic origin or associated with tuberous sclerosis (TS). TS-associated AMLs often present in childhood, tend to be bilateral and multiple, and often exhibit a faster growth rate with an increased risk of hemorrhage. Renal cryoablation is well described in adults, whereas experiences with adolescents and young adults are limited. We present here for the first time a series of renal AMLs within adolescents and young adults treated with laparoscopic assisted cryoablation (LCA). OBJECTIVE: The aim was to evaluate whether LCA of AMLs in adolescents and young adults is a safe and feasible treatment modality. STUDY DESIGN: From October 2009 to September 2013 a total of five patients at our institution were diagnosed with AMLs requiring treatment. Four patients had TS and one had AML of sporadic origin, all five patients underwent LCA. Data were retrospectively collected by a systematic review of patient material and reassessment of renal imaging. RESULTS: The median age was 16 years (range 13-27 years). Eight AMLs with a median size of 3.9 cm (range 2.1-7.7 cm) were treated in five patients because of tumor size and rapid growth. Follow-up was a median 37 months (range 20-62 months), and all tumors showed a reduction in tumor size, and no regrowth was recognized (see summary table). The procedure was well tolerated, with only few perioperative complications and no postoperative complications. DISCUSSION: When considering the indication for treating AMLs, the origin (sporadic or TS associated) and size of the tumor are the decisive factors. To preserve renal function and prevent spontaneous hemorrhage caution should be intensified when tumors reach 4 cm, particularly if TS is present. After the diagnosis is established, patients should be monitored with renal imaging at regular intervals to identify rapid-growing tumors. As an alternative to current treatment modalities such as partial nephrectomy and super selective angioembolization, cryoablation is an emerging approach, although experience with pediatric patients is limited. For patients not requiring immediate surgery, pharmacological treatment with mTOR inhibitors is now being evaluated as an alternative treatment option or as neo-adjuvant therapy to ablative techniques. CONCLUSION: Prophylactic treatment of large or rapid growing AMLs with LCA appears to be a safe and feasible nephron-sparing approach in adolescents and young adults. The low perioperative complication rate and promising effect on outcome might allow treatment of subclinical AMLs in order to minimize the risk of potentially life-threatening complications and preserve renal function.