Management of Sporadic Renal Angiomyolipomas: A Systematic Review of Available Evidence to Guide Recommendations from the European Association of Urology Renal Cell Carcinoma Guidelines Panel

Evolving horizons in renal angiomyolipoma: two decades of management strategies and clinical perspectives in a single institutional study

OBJECTIVE

To assess various management options for renal angiomyolipoma (AML) to guide clinical practice.

METHODS

A single center retrospectively reviewed an AML series from 2002 to 2022. The image reports and chart reviews of patients who received two abdominal scans at least 6 months between the first and last scans were assessed.

RESULTS

A total of 203 patients with 209 tumors were identified and followed up for a median of 42.6 months. Active surveillance (AS) was the most frequently selected option (70.9% of cases). Interventions were required for 59 AMLs, of which 20 were treated with embolization, 29 with partial nephrectomy, 9 with radical nephrectomy, and 1 with radiofrequency (RF) ablation. The median size of the lesions at intervention was 5 cm. The average growth rate of the lesions was 0.12 cm/year, and there was a significant difference in the average growth rate of lesions ≤4 cm and those >4 cm (0.11 vs. 0.24 cm/year; p = 0.0046).

CONCLUSION

This series on AMLs confirms that lesions >4 cm do not require early intervention based on size alone. Appropriately selected cases of renal AML can be managed by AS.KEYWORDS: Angiomyolipoma; active surveillance; embolization; nephrectomy; nephron-sparing surgery.

Comprehensive Insights Into Renal Perivascular Epithelioid Cell Neoplasms: From Molecular Mechanisms to Clinical Practice

Perivascular epithelioid cell neoplasms (PEComas) are a rare category of mesenchymal tissue tumors, manifesting across various tissues and organs such as the kidneys, liver, lungs, pancreas, uterus, ovaries, and gastrointestinal tract. They predominantly affect females more than males. PEComas characteristically express both melanocytic and smooth muscle markers, making immunohistochemistry vital for their diagnosis. Renal angiomyolipoma (AML) represents a common variant of PEComas, typically marked by favorable prognoses. Nonetheless, only a small fraction of subtypes, especially epithelioid AML, possess the capacity to be malignant. Renal PEComas usually appear as asymptomatic masses accompanied by vague imaging characteristics. The main methods for diagnosis are histopathological analysis and the application of immunohistochemical stains. Presently, a uniform treatment plan for renal PEComas is absent. Strategies for management include active surveillance, selective arterial embolization, surgical procedures, and drug-based treatments. The focus of this review is on renal PEComas, shedding light on their pathogenesis, pathological characteristics, clinical presentations, diagnosis, and treatment modalities, and incorporating a clinical case study.

Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.

Renal angiomyolipoma selective arterial embolization: Australian tertiary centre experience over 10 years

INTRODUCTION

The purpose of this study is to evaluate the patient selection methods, treatment outcomes, complications, clinical and radiological follow-up after renal angiomyolipoma (AML) treatment with selective arterial embolization (SAE) in an Australian metropolitan tertiary centre.

METHODS

This study presents a retrospective single-centre review of patients' medical records who underwent SAE for renal AML during the period of 1st January 2012 and 1st January 2023.

RESULTS

A total of 32 SAE procedures for renal AML occurred during the study period. Three episodes were classified as emergency cases [9.38%] and the remaining 29 were treated electively. Mean AML size pre-treatment was 69.45 mm (range = 33-177; SD = 31.69). All AMLs demonstrated hyper-vascularity on contrast-enhanced cross-sectional imaging (arterial-phase enhancement characteristics and/or prominent tortuous feeding vessels) [n = 32; 100%] or an intralesional aneurysm or pseudoaneurysm [n = 12; 42.85%]. Periprocedural complications [n = 3; 9.38%] included: one intralesional haemorrhage after embolization, one vascular access site complication, and one lipiduria-associated urinary tract infection. No patients suffered a life-threatening complication, non-target embolization, deterioration in renal function or death following SAE. Re-treatment with SAE was performed in only three patients [10.71%]. Hospital mean length of stay was 1.58 days. Median durations of clinical and radiological follow-up post-treatment were 493 days (range = 104-1645) and 501 days (range = 35-1774), respectively. Follow-up imaging revealed AML total size reduction in all cases [mean = -17.17 mm; -26.51%] and 50% had obliteration of lesion hyper-vascularity after one episode of SAE. Outpatient clinical follow-up signifies that none of the patients included in the study have re-presented with lesion haemorrhage after successful SAE.

CONCLUSION

In this study, renal AMLs were treated safely with a high degree of success by using SAE, and there were very low rates of periprocedural complications. Follow-up of patients after SAE treatment of renal AML should include both radiological (assessment for reduction in lesion vascularity and size) and clinical review in an outpatient clinic setting (either by an interventional radiologist or urologist).

Natural history of renal angiomyolipoma in a high-volume center: our experience during more than 15 years of follow up

OBJECTIVES

To describe the natural history of AML, the clinical results and the need for treatment during long-term follow-up of renal AML.

METHODS

Retrospective study of patients diagnosed with AML by computed tomography or nuclear magnetic resonance between 2001 and 2019, with at least two follow-up images. Clinical and imaging variables, need for intervention, complications and follow-up time were recorded. Statistical analysis was performed using SPSS 22.0.

RESULTS

111 patients and 145 AML were included. The median follow-up was 6.17 years (range 0.7-18.1, IQR 11.8-12.2). The median tumor size at diagnosis was 13 mm (IQR 7.5-30), with 24 (16.4%) being ≥ 4 cm. Most presented as an incidental finding (85.5%); in 3 (2.1%) cases, the presentation was as a spontaneous retroperitoneal hematoma. The main indication for intervention was size ≥ 4 cm in 50%. Eighteen (12%) patients received a first intervention, being urgent in 3. Embolization was performed in 15 cases and partial nephrectomy in 3. The need for reintervention was recorded in five: two underwent partial nephrectomy and two total nephrectomy; one patient required a new urgent embolization. Of the non-operated patients, 43% decreased in size or did not change, while 57% increased, with the median annual growth being 0.13 mm (IQR - 0.11 to 0.73). There were no differences in the median growth in tumors measuring ≥ 4 cm (0.16 mm) at diagnosis vs. < 4 cm (0.13 mm) (p = 0.9).

CONCLUSIONS

The findings of this study suggest that AML typically demonstrate a slow-progressing clinical course during long-term follow-up. Moreover, our observations, which cast doubt on tumor size as a reliable predictor of adverse clinical outcomes, advocate for a less intensive monitoring strategy in both monitoring frequency and choice of imaging modality.

The radiomics-clinical nomogram for predicting the response to initial superselective arterial embolization in renal angiomyolipoma, a preliminary study

Purpose

The aim of this study was to explore a radiomics-clinical model for predicting the response to initial superselective arterial embolization (SAE) in renal angiomyolipoma (RAML).

Materials and methods

A total of 78 patients with RAML were retrospectively enrolled. Clinical data were recorded and evaluated. Radiomic features were extracted from preoperative contrast-enhanced CT (CECT). Least absolute shrinkage and selection operator (LASSO) and intra- and inter-class correlation coefficients (ICCs) were used in feature selection. Logistic regression analysis was performed to develop the radiomics, clinical, and combined models where the fivefold cross-validation method was used. The predictive performance and calibration were evaluated by the receiver operating characteristic (ROC) curve and calibration curve. Decision curve analysis (DCA) was used to measure clinical usefulness.

Results

The tumor shrinkage rate was 29.7% in total, and both fat and angiomyogenic components were significantly reduced. In the radiomics model, 12 significant features were selected. In the clinical model, maximum diameter (p = 0.001), angiomyogenic tissue ratio (p = 0.032), aneurysms (p = 0.048), and post-SAE time (p = 0.002) were significantly associated with greater volume reduction after SAE. Because of the severe linear dependence between radiomics signature and some clinical parameters, the combined model eventually included Rad-score, aneurysm, and post-SAE time. The radiomics-clinical model showed better discrimination (mean AUC = 0.83) than the radiomics model (mean AUC = 0.60) and the clinical model (mean AUC = 0.82). Calibration curve and DCA showed the goodness of fit and clinical usefulness of the radiomics-clinical model.

Conclusions

The radiomics-clinical model incorporating radiomics features and clinical parameters can potentially predict the positive response to initial SAE in RAML and provide support for clinical treatment decisions.

A Case of Life-threatening Rupture of Small Renal Angiomyolipoma with an Unidentified Intratumoral Aneurysm during Follow-up

We report a case of a life-threatening ruptured renal angiomyolipoma (AML) that did not meet the criteria for prophylactic treatment (tumor >4 cm or intratumoral aneurysm >5 mm) during follow-up. A woman in her 70s was followed up for a 2.5-cm AML with a rich vascular component. An intratumoral aneurysm >5 mm was not identified for 2 years. She complained of a sudden abdominal pain with hypotension, and contrast-enhanced computed tomography revealed a retroperitoneal hematoma with contrast media extravasation from an intratumoral aneurysm. Emergency transcatheter arterial embolization was successfully performed using N-butyl cyanoacrylate glue. Rupture can occur in small AMLs or in AMLs not identified with intratumoral aneurysms during follow-up. AMLs with a rich vascular component at the kidney surface are more likely to rupture.

The association between computed tomography attenuation value of renal angiomyolipoma associated with tuberous sclerosis complex and response to everolimus

BACKGROUND

The response to everolimus in patients with renal angiomyolipoma associated with tuberous sclerosis complex (TSC-RAML) varies among individuals. This study aims to identify potential factors associated with the response to everolimus.

METHOD

We retrospectively examined data encompassing age, gender, tumor size, computed tomography attenuation value (CT value), CT enhancement, and tumor reduction rate in patients with TSC-RAML undergoing everolimus in two previously registered clinical trials.

RESULT

A total of 33 participants (29.33 ± 6.63 years old, 20 females) were included. The correlation analysis conducted separately for tumors located in the left and right kidneys revealed significant negative correlations (P < 0.05) between tumor reduction rate and age, as well as tumor size. While significant positive correlations (P < 0.05) were observed between tumor reduction rate and unenhanced CT value as well as CT enhancement. Nonetheless, based on multiple linear regression analysis, unenhanced CT value emerged as the sole-independent predictor of tumor reduction rate among age, gender, tumor size, unenhanced CT value and CT enhancement for both left (coefficient = 0.00319, P < 0.0001) and right kidneys (coefficient = 0.00315, P = 0.0104). Notable reductions were observed in unenhanced CT value (- 3.81 vs - 24.70HU, P < 0.0001) and CT enhancement (48.16 vs 33.56HU, P < 0.0001) following a 3-month administration of everolimus. The decline in both unenhanced CT value and tumor size predominantly occurred within the initial 3 months, subsequently maintaining a relatively stable level throughout the treatment.

CONCLUSION

The unenhanced CT value of TSC-RAML showed an independent correlation with the response to everolimus, suggesting its potential as a predictor of everolimus efficacy in patients with TSC-RAML.

Renal angiomyolipoma: from imaging to intervention

A high volume of cross-sectional imaging has created a window of opportunity for radiologists to identify renal angiomyolipomas (AMLs). The purpose of this review is to help the reader recognise the spectrum of renal AML appearances using different imaging methods and to gain an understanding of the classic and atypical features for appropriate lesion characterisation. Risk factors for AML growth and rupture will be highlighted. An overview of the imaging features of acute AML rupture will be provided, principally relating to computed tomography (CT) assessment. A series of cases will be presented, including a case of peripartum renal AML rupture during Caesarean section leading to diagnostic dilemma. The indications for intervention and available treatment options will be considered: medical therapy, surgery, and interventional radiology (IR) techniques including their pros and cons. Emergency interventional radiology management with selective transarterial embolisation will be presented and analysed in relation to technique, angiographic appearances (pre and post embolisation) and associated complications.

Long-term efficacy of selective arterial embolisation of renal angiomyolipoma

OBJECTIVE

To evaluate the long-term efficacy of selective arterial embolisation in renal angiomyolipoma (AML), with emphasis on tumour shrinkage, potential regrowth and the necessity of supplementary procedures.  Material and methods: A retrospective review of all 58 consecutive embolisations at two institutions, between 1999 and 2018, was performed. Clinical notes, laboratory data and imaging were reviewed.

RESULTS

The overall complication rate was 6.8%, with no Clavien-Dindo grades III-V complications. Kidney function was unaffected by embolisation as measured by creatinine. Median radiological follow-up was 4.8 years (interquartile range [IQR]: 2.8-7.8), and median clinical follow-up was 7.5 years (IQR: 4.7-14.0). Decreasing AML size was observed in 96% of procedures. Maximal shrinkage (30% median diameter decrease; IQR: 15-44) was reached after median 2.2 years (IQR: 0.6-4.8). During follow-up, regrowth occurred in 38% of patients, and four bleeding episodes occurred in three patients with tuberous sclerosis. Growing size and/or rebleeding prompted a redo embolisation in 9% of spontaneous AML and 50% of tuberous sclerosis-associated AML.

CONCLUSIONS

Being a well-tolerated treatment with few complications, selective arterial embolisation renders a pronounced size-reduction in most patients with AML, and kidney function is preserved. Regrowth is common, and a radiological follow-up is necessary. Tuberous sclerosis is a risk factor for the need of reintervention.

Clinical study of renal artery cold perfusion combined with laparoscopic nephron retention in the treatment of complex renal angiomyolipoma

Objective

The aim of this study is to summarize the surgical experience of renal artery cold perfusion combined with laparoscopic nephron preserving surgery for the treatment of complex renal angiomyolipoma and to evaluate the safety and feasibility of this surgical protocol.

Materials and methods

Clinical data of nine patients who received renal artery cold perfusion combined with laparoscopic nephron preserving surgery for complex renal angiomyolipoma in our hospital from February 2017 to August 2020 were retrospectively analyzed. The study parameters included imaging findings, total renal function before and after surgery, glomerular filtration rate (GFR) of affected kidney before and after surgery, and related complications.

Results

Eight of the nine patients successfully completed the operation, one patient was intolerant to renal artery balloon implantation, and the success rate of the operation was 88.89%. The mean maximum tumor diameter was 6.8 cm, and RENAL score was 7 points. Postoperative total renal function and GFR of the affected kidney had no significant changes compared with that before surgery, and imaging examination showed no tumor residue or recurrence.

Conclusion

This surgical procedure is safe and feasible for complex renal angiomyolipoma and can be used as a surgical option for renal hamartoma. The long-term effect needs to be confirmed by further studies.

Clinical Practice Guidelines for tuberous sclerosis complex-associated renal angiomyolipoma by the Japanese Urological Association: Summary of the update

New clinical issues have been raised through an interval of 7 years from the previous version (2016). In this study, we update the "Clinical Practice Guidelines for tuberous sclerosis complex-associated renal angiomyolipoma" as a 2023 version under guidance by the Japanese Urological Association. The present guidelines were cooperatively prepared by the Japanese Urological Association and Japanese Society of Tuberous Sclerosis Complex; committee members belonging to one of the two societies or specializing in the treatment of this disease were selected to prepare the guidelines in accordance with the "Guidance for preparing treatment guidelines" published by Minds (2020 version). The "Introduction" consisted of four sections, "Background Questions (BQ)" consisted of four sections, "Clinical Questions (CQ)" consisted of three sections, and "Future Questions (FQ)" consisted of three sections (total: 14 sections). Concerning CQ, an agreement was confirmed through voting by the committee members based on the direction and strength of recommendation, accuracy of evidence, and recommendation comments. The present guidelines were updated based on the current evidence. We hope that the guidelines will provide guiding principles for the treatment of tuberous sclerosis complex-associated renal angiomyolipoma to many urologists, becoming a foundation for subsequent updating.

Renal angiomyolipoma: Beyond size criteria for predicting rupture

INTRODUCTION

Renal angiomyolipomas (AMLs) are vascular tumours that while histologically benign, carry a risk of rupture and potentially life-threatening haemorrhage. Selective arterial embolisation (SAE) has been demonstrated as effective treatment; however, given most tumours are asymptomatic, the challenge facing the radiologist is selection of which AML should undergo treatment. This study considers presence and size of intratumoural aneurysm, to advance the readers treatment decision-making beyond historical size criteria.

METHODS

Retrospective cohort analysis of all SAE-treated AML at a quaternary-level institution in the last 10 years was completed independently by two radiologists. Computerised tomography (CT) and angiographic imaging were reviewed to evaluate tumour size, presence of intratumoural aneurysm and aneurysm size. Univariant and multivariant statistical analyses were used to identify predictors of spontaneous rupture and haemorrhage.

RESULTS

Twenty-seven renal AML underwent SAE. Five tumours had presented with haemorrhage. Twenty-two were asymptomatic or without CT/angiographic detectable haemorrhage. There was no statistically significant size difference between ruptured (mean 7.8 cm, range 6.1-12.0 cm) and unruptured AML (7.5 cm, 3.3-21.7 cm) in the study population. Eighty percent of ruptured AML and 27% of unruptured AML contained at least one intratumoural aneurysm (P-value < 0.05). Mean aneurysm size in ruptured AMLs was 5.4 mm, versus 4.6 mm among unruptured AML (P-value > 0.05).

CONCLUSION

The presence of intratumoural aneurysm is a useful predictor for AMLs that are at risk of spontaneous rupture and haemorrhage. Intratumoural aneurysm should therefore be considered when selecting patients to undergo SAE.

Effectiveness of everolimus for sporadic renal angiomyolipoma with inferior vena cava thrombus: A case report

Sporadic Renal Angiomyolipoma (AML) is commonly managed through transcatheter arterial embolization (TAE) or surgical intervention. In this report, we present a remarkable case of tumor regression from Novick Classification level 2 to level 1 in a 54-year-old male with sporadic renal AML and inferior vena cava (IVC) involvement, treated with the administration of everolimus. Subsequently, laparoscopic nephrectomy without cavectomy was performed. Notably, the patient did not present with tuberous sclerosis complex (TSC). Our findings highlight the potential of everolimus in the treatment of sporadic AML, even in cases unrelated to TSC, offering a viable alternative to invasive therapeutic approaches.

Serum lactate dehydrogenase concentration after transcatheter renal artery embolization correlates with reduction in renal angiomyolipoma volume

BACKGROUND

The extent of renal angiomyolipoma (AML) volume reduction after renal transcatheter arterial embolization (TAE) varies between patients, with no predictive measure available.

PURPOSE

To determine whether the serum lactate dehydrogenase (LDH) concentration shortly after TAE correlates with the extent of tumor shrinkage.

MATERIAL AND METHODS

In a cohort of 36 patients undergoing prophylactic renal TAE for unruptured renal AML, we retrospectively acquired data from patient medical records, including serum LDH before and within 7 days after TAE and the tumor volume before and 12-36 months after TAE. The relationship between the serum level of LDH and reduction in tumor volume was evaluated using Spearman correlation analysis.

RESULTS

The median LDH concentration was significantly higher after TAE than before (909.0 U/L vs. 186.5 U/L). This early post-TAE serum LDH level and LDH index (post-TAE LDH / pre-TAE LDH) correlated significantly and positively with the absolute decrease in tumor volume (both P < 0.0001). We observed no significant correlation between the relative tumor volume reduction and serum LDH level or LDH index.

CONCLUSION

Serum LDH elevation occurs shortly after TAE and correlates with the extent of absolute decrease in AML volume at 12-36 months after TAE. Further large-scale studies are warranted to confirm the predictive role of post-TAE serum LDH level and LDH index in tumor shrinkage in patients with unruptured renal AML.

Safety, Efficacy and Mid-Term Outcome for Transarterial Embolization (TAE) of Renal Angiomyolipoma (AML) Using Ethylene Vinyl Alcohol Copolymer Liquid Embolic Agent (EVOH)

Transarterial embolization (TAE) of renal angiomyolipoma (AML) is effective in treating and preventing hemorrhage. We report our experience using EVOH with a single-center retrospective study of all AML embolized with EVOH between June 2013 and March 2022 at the Montpellier University Hospital. A total of 29 embolizations were carried out in 24 consecutive patients (mean age: 53.86 years; 21 women and 3 men) with 25 AMLs for severe bleeding, symptomatic AML, tumor size > 4 cm, or presence of aneurysm(s) > 5 mm. Data collected included imaging and clinical outcomes, tuberous sclerosis complex status, change in AML volume, rebleeding, renal function, volume and concentration of EVOH used, and complications. Out of 29 embolizations performed for 25 AMLs, four were performed in an emergency. Technical success was achieved for 24/25 AMLs. Mean AML volume reduction was 53.59% after a mean follow-up time of 446 days using MRI or CT scan. Aneurysms on angiogram and the symptomatological nature of AML, as well as secondary TAE and multiple arterial pedicles, were statistically associated (p < 0.05). Two patients (8%) underwent nephrectomy after TAE. Four patients had a second embolization. Minor and major complication rates were 12% and 8%, respectively. Neither rebleeding nor renal function impairment was noticed. TAE of AML using EVOH is, thus, highly effective and safe.

Is Size All That Matters? New Predictors of Complications and Bleeding in Renal Angiomyolipoma

Purpose

Renal angiomyolipoma (AML) is the most common benign renal tumor. Whilst generally asymptomatic, they can cause life-threatening bleeding. Selective angioembolization (SAE) may be used to treat large symptomatic and asymptomatic AMLs. We aimed to evaluate the efficacy of SAE for symptomatic and asymptomatic renal AMLs and determine characteristics that predict spontaneous bleeding.

Patients and Methods

Data were retrospectively collected from a prospectively maintained database from July 2011 to April 2022. Patients were included if AML was >4cm and they underwent subsequent SAE. Follow-up imaging was analyzed to calculate mean reduction in AML size. Clinical notes were reviewed to analyze lesion characteristics including vascularity, fat content and presence of aneurysm as well as post-procedural complications.

Results

26 patients with 30 AMLs were identified. Interval of follow-up imaging ranged from 1 to 60 months. 25 AMLs were embolized electively with 5 emergency embolizations performed for bleeding. Mean reduction in AML volume was 41% at 3 months (p=0.013) and 63% at 12 months (p=0.007). All 5 bleeding AMLs had a rich vascularity with 60% also having either aneurysms or a low fat content. Complications included post-embolic syndrome (n=9), segmental renal parenchyma devascularization (n=3), acute bleeding requiring re-embolization (n=2), nephrectomy for ongoing bleeding (n=1) and delayed bleeding managed conservatively (n=1). No deterioration in renal function was observed.

Conclusion

SAE is an effective procedure for managing symptomatic and asymptomatic renal AML, with minimal significant complications. AML vascularity, fat content and aneurysms may be useful characteristics to assess future risk of bleeding in patients with renal AML.

Renal Functional Outcomes in Patients With Angiomyolipomas: Surveillance vs Embolization vs Nephrectomy

OBJECTIVE

To investigate renal functional outcomes of surveillance, embolization, and surgery for angiomyolipomas (AML).

METHODS

Longitudinal data regarding patients with AML were analyzed retrospectively in this 2-center study. Demographic, radiographic, and functional data were tabulated according to treatment type. Primary outcome was change in renal function from diagnosis to within 6 months postdiagnosis (interim) and to latest glomerular filtration rate (GFR) assessment.

RESULTS

318 patients were diagnosed with AMLs; mean follow-up was 6.2 years. 184 patients (57.9%) were managed with surveillance, 30 (9.4%) underwent embolization, and 103 (32.4%) underwent surgery (91 partial nephrectomy; 12 radical nephrectomy). Baseline characteristics, including tumor size, age, and race differed between the 3 groups (P<.05). Surveilled AMLs were smaller (P<.001) than the intervention groups: 1.9 cm vs 5.4 cm (embolization) and 4.9 cm (surgery). Greater interim decreases in GFR were observed following intervention with embolization (-14.0%) or surgery (-11.8%), when compared with surveillance (-4.1%); however, this was not statistically significant (P=.19). Latest GFR was also reduced more (P=.02) with embolization (-14.1%) and surgery (-14.7%) when compared to surveillance (-6.0%). At latest determination, chronic kidney disease progression by at least one stage occurred in 37.8% overall, including 33.7% of surveilled patients, and was not statistically different across the three cohorts (P=.074).

CONCLUSION

Within the study limitations, surveillance appears to be appropriate for most AML patients; embolization and surgical intervention should be reserved for selected patients with large and/or symptomatic AML. Renal functional deterioration is common in patients with AML, whether managed with surveillance, embolization, or surgery. Long-term monitoring of renal function should be obligatory for all AML patients.

Angiomyolipoma of the kidney-Clinicopathological analysis of 52 cases

The renal angiomyolipoma (AML) is a benign tumor characteristically composed of fat, smooth muscle tissue, and vessels. We collected AMLs from our nephrectomy database, reclassified them according to their histological appearance, recorded the demographic, clinical, and pathological parameters, and compared them with oncocytoma (RO) and renal cell carcinoma (RCC). Immunohistochemistry was ordered in 41 cases. In 2224 nephrectomies, we found 52 AMLs with a 53 mm median size. The mean age was 52.76. Forty-eight tumors were sporadic, while four were hereditary. The revision resulted in 31 classic, 13 leiomyoma-like, five lipoma-like, two epithelioid, and one AML with epithelial cysts. SMA was diffusely positive, except for the epithelioid type, while MelanA harbored stronger expression than HMB45. AML was more frequent in females and appeared ten and 7 years earlier than RO and RCC, respectively. The follow-up time was 7.42 years, and neither tumor-related death nor relapse occurred. AML is rare in nephrectomies and develops primarily in females in their 50s with an average size of 50-60 mm at the surgery. The histological appearance in order of frequency is classic, leiomyoma-like, lipoma-like, epithelioid, and cystic. The MelanA, HMB45, and SMA immunohistochemistry can support the light-microscopic findings.

Sporadic Renal Angiomyolipoma: Can We Adopt a Uniform Management Protocol?

Renal angiomyolipomas (AMLs), formerly known as PEComas (tumors showing perivascular epithelioid cell differentiation) are common benign renal masses composed of a varying ratio of fat, blood vessels, and smooth muscles. They are largely asymptomatic and diagnosed incidentally on imaging.

The adipose tissue content is the factor that gives AMLs their characteristic appearance on imaging and makes them easily identifiable. However, the fat-poor or fat-invisible varieties, which are difficult to differentiate radiologically from renal cell carcinomas (RCCs), present a diagnostic challenge. It is thus essential to establish the diagnosis and identify the atypical and hereditary cases as they require more intense surveillance and management due to their potential for malignant transformation.

Multiple management options are available, ranging from conservative approach to embolization and to the more radical option of nephrectomy. While the indications for intervention are relatively clear and aimed at a rather small cohort, the protocol for follow-up of the remainder of the cohort forming the majority of cases is not well established. The surveillance and discharge policies therefore vary between institutions and even between individual practitioners. We have reviewed the literature to establish an optimum management pathway focusing on the typical AMLs.

Safety, Efficacy, and Predictors for Late Reintervention After Embolization of Renal Angiomyolipomas – Embolization renal angiomyolipoma

Purpose To retrospectively analyze the procedural and long-term clinical outcome of the selective embolization of renal angiomyolipoma. In addition, potential predictive factors for higher risk of late re-intervention were analyzed.

Methods Retrospective monocentric study, including 34 consecutive patients, analyzing the safety, efficiency, and long-term clinical outcome of catheter-directed embolization of renal AML. Additionally, the difference in postembolization renal function between patients embolized in the acute and in the elective setting was analyzed. Secondly, we also evaluated whether volume/diameter of the AML and presence of intralesional aneurysms are risk factors for late re-intervention.

Results Embolization of renal AML was performed to control volume (n = 21; 62 %) or to stop spontaneous hemorrhage (n = 13; 38 %) with angiographic success in all cases but was associated with renal abscess (n = 1) and pulmonary embolism (n = 1) without a significant difference in renal function before and after embolization (P = 0.513). Volume/diameter (P = 0.276/P = 0.21) and presence of aneurysms before embolization (P = 0.37) are not predictive for a higher risk of late re-intervention.

Conclusion Catheter-directed embolization is a safe and effective treatment modality for asymptomatic and bleeding renal AML, without a negative impact on renal function. Initial mass volume/diameter or presence/absence of intralesional aneurysms does not seem to be predictive for late re-intervention.

Key Points:

Citation Format

Imaging of renal emergencies: Review of infectious, hemorrhagic, vascular, and traumatic etiologies

Diagnostic imaging allows for accurate and early recognition of acute renal pathologies, thus allowing for appropriate clinical triage, life-saving treatments, and preservation of renal function. In this review, we discuss the clinical presentation and imaging findings of renal emergencies with infectious, hemorrhagic, vascular, and traumatic etiologies.

Spontaneous rupture of renal angiomyolipoma and its management: A case report

a) Introduction and Importance

Angiomyolipomas of kidney are benign lesions that are generally an incidental finding on imaging. Rupture of angiomyolipoma is rare and fatal complication that requires early intervention.

b) Case Presentation

A 38 year old male patient presented with symptoms of right flank pain for 2 days. On clinical examination patient looked anxious, pale with right flank tenderness, guarding and signs of shock.

c) Clinical findings and investigations

CT scan showed renal angiomyolipoma with aneurysm formation and bleed from the lesion. Blood profile revealed low hemoglobin.

d) Interventions and Outcome

Right nephrectomy performed along 6 cycles of cardiopulmonary reususcitaion done with stable post operatively vitals.

e) Conclusion

Early diagnosis of complication of angiomyolipoma requires thorough clinical examination and judicious use of imaging. Immediate embolization or surgery must be performed for better outcome and survival rate.

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Angiomyolipoma is composed of fat, smooth muscle and blood vessels and presents among 0.3% of the population.

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Renal angiomyolipoma are prone to aneurysm formation and bleed, however a nontraumatic spontaneous renal hemorrhage from a sporadic renal angiomyolipoma is a rare condition.

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Mostly angiomyolipoma are asymptomatic and are diagnosed incidentally. CT scan is the diagnostic modality of choice.

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Patients with life-threatening hemorrhage require immediate intervention that includes embolization or surgery for better outcome and survival rate.

Transarterial Embolization for Sporadic Renal Angiomyolipoma: Patient Selection and Technical Considerations for Optimal Therapeutic Outcomes

Although renal angiomyolipoma (AML) is a benign tumor, treatment may be necessary occasionally because it can cause potentially life-threatening retroperitoneal hemorrhage. Transarterial embolization (TAE) is a safe and effective treatment option to prevent the hemorrhagic rupture of AMLs and relieve the symptoms caused by enlarged lesions or active bleeding. However, there is no clear consensus regarding the indications for prophylactic TAE in patients with sporadic renal AMLs. In urgent TAE for bleeding AMLs, there is a likelihood of incomplete embolization when the focus is on stabilizing the clinical symptoms. This pictorial essay discusses the patient selection and technical considerations to achieve optimal therapeutic effects as well as the follow-up findings after TAE.

Deep Learning Plus Three-Dimensional Printing in the Management of Giant (>15 cm) Sporadic Renal Angiomyolipoma: An Initial Report

Objective

To evaluate the feasibility and effectivity of deep learning (DL) plus three-dimensional (3D) printing in the management of giant sporadic renal angiomyolipoma (RAML).

Methods

The medical records of patients with giant (>15 cm) RAML were retrospectively reviewed from January 2011 to December 2020. 3D visualized and printed kidney models were performed by DL algorithms and 3D printing technology, respectively. Patient demographics and intra- and postoperative outcomes were compared between those with 3D-assisted surgery (3D group) or routine ones (control group).

Results

Among 372 sporadic RAML patients, 31 with giant ones were eligible for analysis. The median age was 40.6 (18-70) years old, and the median tumor size was 18.2 (15-28) cm. Seventeen of 31 (54.8%) had a surgical kidney removal. Overall, 11 underwent 3D-assisted surgeries and 20 underwent routine ones. A significant higher success rate of partial nephrectomy (PN) was noted in the 3D group (72.7% vs. 30.0%). Patients in the 3D group presented a lower reduction in renal function but experienced a longer operation time, a greater estimated blood loss, and a higher postoperative morbidity. Subgroup analysis was conducted between patients undergoing PN with or without 3D assistance. Despite no significant difference, patients with 3D-assisted PN had a slightly larger tumor size and higher nephrectomy score, possibly contributing to a relatively higher rate of complications. However, 3D-assisted PN lead to a shorter warm ischemia time and a lower renal function loss without significant difference. Another subgroup analysis between patients under 3D-assisted PN or 3D-assisted RN showed no statistically significant difference. However, the nearness of tumor to the second branch of renal artery was relatively shorter in 3D-assisted PN subgroup than that in 3D-assisted RN subgroup, and the difference between them was close to significant.

Conclusions

3D visualized and printed kidney models appear to be additional tools to assist operational management and avoid a high rate of kidney removal for giant sporadic RAMLs.

Different Treatments of Symptomatic Angiomyolipomas of the Kidney: Two Case Reports

Development of more sensitive imaging techniques has caused an increase in the number of diagnosed small renal tumors. Approximately 2-3% of these lesions are proved to be angiomyolipomas (AML), a rare benign tumor of the kidney sometimes causing pain and hematuria. The most required approach is observation, but in the case of recurrent symptoms or larger tumors, which may cause bleeding, a more active treatment is required. We present two cases of symptomatic AML tumors of different sizes in the kidney: one treated with transarterial embolization (TAE), and the other with percutaneous cryoablation (CRA). The lesions were diagnosed on the basis of contrast-enhanced computed tomography (CT) scan and magnetic resonance imaging (MRI). Both treatments proved to be effective and safe for treating renal AMLs. A follow-up carried out, based on contrast-enhanced CT scan, confirmed complete treatment of AML and decreased lesion size. There are myriad minimally invasive approaches for the treatment of renal AMLs, and the preservation of renal function remains a priority. The most popular treatment option is the selective renal artery embolization. Owing to its limited invasiveness, CRA could be an attractive option for the preventive treatment of AML.

Robot-Assisted versus Laparoscopic Partial Nephrectomy for Giant Sporadic Renal Angiomyolipomas of ≥7 cm: A Propensity Score-Matched Analysis

Background

To compare the perioperative and functional outcomes between robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) for giant sporadic renal angiomyolipomas (AMLs) of ≥7 cm.

Materials and Methods

Patients with sporadic renal AMLs of ≥7 cm who underwent RAPN or LPN in the First Affiliated Hospital of Nanchang University between 2015 and 2020 were retrospectively analyzed. Propensity score matching (1 : 1) was performed to adjust for potential baseline confounders. Perioperative and functional outcomes of the RAPN and LPN groups were collected and compared.

Result

After propensity score matching, no statistically significant differences in baseline characteristics were found between the groups (41 vs. 41). Within the matched cohort, the warm ischemia time (WIT) in the RAPN group was significantly shorter than that in the LPN group (21 vs. 27 min, p < 0.001). In addition, the RAPN group was associated with improved postoperative renal function (72.8 vs. 69.8 mL/min/1.73 m², p=0.045). WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, and renal score and operation method are independent predictors of WIT.

Conclusion

RAPN and LPN are safe and feasible minimally invasive treatments for sporadic giant renal AMLs, but RAPN is associated with shorter WIT and better postoperative renal functional preservation. WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, while the RENAL score and surgical method are independent risk factors to WIT. For giant and complex renal AMLs, RAPN is the first choice when condition permits.

Selective arterial embolization of renal angiomyolipomas: A 10‐year experience

Objectives

To study safety and efficacy of selective endovascular trans‐arterial embolization (TAE) of renal angiomyolipoma (AML) in a 10‐year period at a regional tertiary referral center in Denmark.

Patients and methods

All 56 patients who underwent TAE of renal AML at Departments of Urology and Radiology, Copenhagen University Hospital – Rigshospitalet, Denmark, from 2009 to 2020 were included. Seven without preoperative and postoperative imaging were excluded, leaving 49 patients for analysis. From national electronic medical records, we retrieved patient characteristics, surgical data, and follow‐up data. Tumor size at the time of embolization and during follow‐up was compared using Student's paired t test. Estimated glomerular filtration rate (eGFR) pre‐ and post‐embolization were compared using Wilcoxon rank sum test.

Results

We included 49 patients of whom 4 had two tumors treated in the same TAE procedure. Median age was 50 years (interquartile range [IQR]: [29–67 years]), and the median follow‐up time was 4.6 years [IQR: 3.0–6.7 years]. Post‐embolization syndrome (PES) was experienced in 27 patients, and non‐PES in 5 patients. Median length of hospital stay was 0 days [IQR, 0–1]. Postoperative Everolimus immunosuppressive treatment was offered to seven patients. Median tumor size was 6.0 cm [IQR: 4.6–7.9 cm] and was significantly reduced to 3.7 cm [IQR: 2.5–5.2 cm] after treatment (p < 0.001). Kidney function was not affected by TAE. Three deaths, not related to AML, were noted during follow‐up.

Conclusion

Embolization of AML was in this cohort effective to significantly reduce tumor size without serious adverse events and loss of renal function. TAE is a safe and efficacious treatment and the preferred minimally invasive treatment option of AML.

Is There a Higher Incidence of Sporadic Renal Angiomyolipoma in Childhood Cancer Survivors?

Background

Cancer treatment can cause various long-term side effects, including those that impact ultrasound findings. During follow-up of childhood cancer survivors (CCSs), we often detected sporadic renal angiomyolipomas without histological confirmation (SAMLs), which is why we initiated this study. We compared the occurrence of SAML in CCSs to the previously reported data from a non-cancer population and correlated SAML with cancer treatment-related factors.

Methods

The cohort included 1098 CCSs (median age at cancer diagnosis (dg) 4.3 years) who had ultrasound follow-up (2014-2019). Of the CCSs, 525 (48%) were female, 132 (12%) had subsequent neoplasms (SNs), and 110 (10%) had genetic syndromes. CCSs were treated for lymphomas 269 (24%) and solid tumors 829 (76%). None of the CCSs had tuberous sclerosis complex (TSC).

Results

SAML developed in 48 (4.4%) CCSs; of these, 20 (42%) had SNs. The coincidence of SAMLs and SNs was found in CCSs with a follow-up period exceeding 20 years. The median age at SAML dg was 27.9 years (interquartile range (IQR) 22.3-34.1), and the median time to SAML dg was 22.6 years (IQR 17.4-27.6). Twenty-one (44%) CCSs developed multiple or bilateral SAMLs lesions; of these, six (12%) were in the radiotherapy field. SAML occurrence correlated with radiotherapy of the retroperitoneum (1.65-fold higher with 95% CI 0.90-3.02). The correlations with other cancer treatment factors and with female sex were less clear.

Conclusion

This study revealed the occurrence of SAMLs in CCSs to be 10 times higher than that in non-cancer studies. The current characteristics of CCSs with SAMLs: younger age, and more bilateral or multiple lesions are more similar to TSC associated angiomyolipoma. Moreover, we observed a coincidence of SAMLs with SNs. Our results support the hypothesis that SAML development in CCSs is not simply a late effect of therapy, and indicates other factors are involved in SAML development.

Sporadic, classic-type renal angiomyolipoma with renal vein and inferior vena cava extension: an incidental case

Renal angiomyolipomas (AMLs) were first described in the early 1900s by Gravitz, but it was not until 1951 that they were named renal AML. These kidney tumours are rare, occurring in 0.13%-0.44% of the population. These mesenchymal tumours are composed of smooth muscle-like, adipocyte-like and epithelioid cells. Depending on the predominant cell population, it can be further subclassified into classic, epithelioid and AML with epithelial cyst. A 32-year-old woman presented with mild, intermittent, epigastric and right upper quadrant abdominal pain. Abdominal ultrasound revealed an incidental lesion within the inferior vena cava (IVC). A CT scan showed a lesion within the left renal vein extending into the IVC with 40% narrowing and a fat-containing mass in the lower pole of the left kidney of 15 mm suggesting an AML. Thrombectomy was performed. The specimen resulted positive for classic variant renal AML. Initial diagnosis is centred on imagining studies, based in fatty tissue concentration. The AML expresses melanocytic markers. This helps differentiate from renal cell carcinoma. Although AML is considered a benign condition, there is evidence of malignant transformation. Active surveillance is recommended for lesions <4 cm. Nephron sparing surgery is the procedure of choice. Nephrectomy is recommended if there is a high probability of malignancy. Mammalian target of rapamycin (mTOR) inhibitors have been proposed to be an alternative treatment.

Giant renal pseudoaneurysm complicating angiomyolipoma in a patient with tuberous sclerosis complex: An unusual case report and review of the literature

Introduction

Angiomyolipomas (AMLs) are uncommon benign lesions, which are composed of dysmorphic blood vessels, adipose tissue, and smooth muscle components. They tend to bleed because of the hypervascularity and the presence of small aneurysms, leading to life-threatening complications.

Presentation of case

A 31-year-old female was presented to the emergency service of our hospital, complaining of left flank pain for 1 week followed by hematuria for one day. Radiologic imaging showed the features of a giant renal pseudoaneurysm. Superselective embolization was applied and she had an uneventful recovery.

Discussion

The blood vessels in AML are tortuous and thick-walled with the absence of supportive elastic tissue, which tend to the formation of the intralesional pseudoaneurysm. The risk of bleeding is higher with tumors larger than 4 cm, rapid tumor growth, and aneurysms larger than 0.5 cm. Early detection and treatment are essential for the prevention of bleeding and improving patient outcomes.

Conclusion

Giant pseudoaneurysm in a renal angiomyolipoma associated with tuberous sclerosis complex is a rare entity, often leading to potentially life-threatening bleeding. Selective angioembolization is recommended as firstline therapy for bleeding AML and is increasingly used as a preventive treatment for AML at risk of bleeding. However, a high incidence of the recurrence requires caution and a close longtime follow-up. Surgical intervention is indicated if the hemorrhage is not responsive to embolization or if there is suspicion of malignancy.

•

Renal pseudoaneurysm is a rare, but potentially life-threatening complication of tuberous sclerosis-related angiomyolipoma.

•

Early detection is essential for the prevention of bleeding and improving the patient outcomes.

•

Selective angioembolization is recommended as firstline therapy for bleeding angiomyolipoma.

•

Surgical intervention is indicated if the hemorrhage is not responsive to embolization.

Off-clamp Retroperitoneoscopic Tumour Evacuation for Sporadic Renal Angiomyolipomas with High RENAL Nephrometry Scores: A Novel Surgical Technique and Its Outcomes

BACKGROUND

Partial nephrectomy or angioembolisation is commonly used for sporadic renal angiomyolipomas (RAMLs) with high RENAL scores, but there is a risk of reduced renal function, postoperative complications, and recurrence.

OBJECTIVE

To describe a new technique for off-clamp laparoscopic evacuation of sporadic RAMLs with high RENAL scores that promotes maximal renal function maintenance and low postoperative complication and lesion recurrence rates.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort of patients undergoing off-clamp laparoscopic evacuation for sporadic RAMLs with RENAL scores ≥9 from January 2013 to June 2018 was included.

SURGICAL PROCEDURE

We highlighted the curettage, suction, packing, and binding (CSPB) technique, a new off-clamp retroperitoneoscopic evacuation technique for sporadic RAMLs.

MEASUREMENTS

Demographics, preoperative, intraoperative, and postoperative outcomes were assessed.

RESULTS AND LIMITATIONS

A total of 141 cases were included. The median (interquartile range [IQR]) tumour size was 7 (6.2-8.2)cm. The median (IQR) RENAL score was 10 (9-11). The median (IQR) operative time was 80 (65-125) min, with a median (IQR) estimated blood loss of 130 (90-362.5)ml. Conversion to neither open surgery nor standard laparoscopy occurred. The warm ischaemia time was zero for all cases. Postoperatively, 13 minor complications (Clavien grade 1) were recorded. No blood transfusions were reported. The glomerular filtration rate did not change significantly from preoperative period to 12-mo follow-up. Recurrence did not occur at the median follow-up period of 48 (36-60) mo. The retrospective design and lack of a control group are limitations of this study.

CONCLUSIONS

Off-clamp retroperitoneoscopic tumour evacuation using the CSPB technique is feasible, safe, and effective for treating complex sporadic RAMLs.

PATIENT SUMMARY

We report a curettage, suction, packing, and binding technique for off-clamp retroperitoneoscopic evacuation of sporadic renal angiomyolipomas that leads to complete lesion clearance, excellent renal function preservation, and minimal perioperative complications.

[Results of active surveillance for sporadic renal angiomyolipomas greater than 4cm: A pledge for active surveillance]

INTRODUCTION

Active surveillance (AS) of sporadic renal angiomyolipomas (AML) is under-utilised because of an old dogma fearing a life-threatening retroperitoneal hemorrhage when tumour size exceeds 4cm. The objective of this study was to report the outcome of AS in patients with sporadic AML greater than 4cm.

METHODS

The results of AS in 35 patients managed for sporadic renal AML greater than 4cm were analysed. During AS, tumour growth, occurrence of new symptoms and/or complications, discontinuation of AS protocol, reason for discontinuation as well as subsequent treatment options were reported.

RESULTS

Within a median follow-up of 36 months, 16 (46 %) patients discontinued AS at the end of the study period (mean follow-up 55±66, median 36 months). Patients who discontinued AS were more symptomatic at diagnosis but had similar age, mean tumour size and sex ratio. Active treatment-free survival was 66 % at 5 years. Retroperitoneal hemorrhage was reported in 3 (8.5 %) patients. None of these bleedings required transfusion or monitoring in an intensive care unit. Other reasons for discontinuation were pain (37 %), patient preference (19), changes in the radiological appearance of the tumour (19 %), and hematuria (6 %).

CONCLUSION

This study showed that AS in AML bearing patients was feasible even in the setting of tumours larger than 4cm. More than 50% of the patients were still on AS at 5 years. Discontinuation of AS was not related to bleeding complications in most cases.

LEVEL OF PROOF

3.

Natural History of Renal Angiomyolipoma Favors Surveillance as an Initial Approach

BACKGROUND

Traditionally, intervention was recommended for angiomyolipomas (AMLs) >4 cm due to the risk of catastrophic hemorrhage.

OBJECTIVE

To delineate the natural history of AMLs, including growth rates and need for intervention.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review was performed of an AML series from 2002 to 2013, which have been followed prospectively until 2018. We defined lesion size by maximum axial diameter and categorized lesion size at baseline.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A total of 458 patients with 593 AMLs, with a median follow-up of 65.2 mo, were identified. At diagnosis, 534 (90.1%) lesions were ≤4 cm. Forty-three interventions were required for 34 (5.7%) AMLs: 30 were treated with embolization, seven surgery, two with radiofrequency ablation (RFA), three with mammalian target of rapamycin (mTOR) inhibitors, and one with nivolumab when epithelioid AML was confirmed. The median size at intervention was 4.9 cm (range 1.1-29 cm).

RESULTS AND LIMITATIONS

Most (94%) of the lesions grew slowly (growth rate of <0.25 cm/yr) during the period of observation. The number of AMLs <4 cm needed to treat (NNT) prophylactically to prevent one emergent bleed would have been 136 or that to prevent one blood transfusion would have been 205. The NNT (<4 cm) prophylactically to prevent one elective intervention would have been 82. On multivariate analysis, there were significant differences in intervention rates based on tuberous sclerosis complex, size at presentation, and clinical presentation.

CONCLUSIONS

This large single-institution updated series of renal AMLs demonstrates that early intervention is not required, regardless of the traditional 4 cm cut-off. The vast majority of AMLs are indolent lesions that are predominantly asymptomatic and slow growing. Follow-up should be no more frequent than annually.

PATIENT SUMMARY

The majority of angiomyolipomas (AMLs) are indolent, slow-growing lesions that do not require intervention, regardless of size at presentation. We suggest that surveillance is a safe initial approach for patients presenting with AMLs.

A scoring system based on clinical features for the prediction of sporadic renal angiomyolipoma rupture and hemorrhage

The purpose of this study is to analyze the risk factors of sporadic renal hamartoma and establish a risk scoring system, and to intervene in patients with high-risk sporadic renal hamartoma who are prone to rupture and bleeding as soon as possible.Retrospective univariate and multivariate logistic analyzes were conducted for clinical data of 332 sporadic renal hamartoma patients to screen out independent risk factors of tumor rupture. Score of each independent risk factor was calculated. (Calculation formula: the risk coefficient of each factor = the beta regression coefficient of each factor/the minimum value of the beta regression coefficient of all factors, the value of the smallest beta regression coefficient corresponding to all the factors was assigned 1 point. The score of each factor was equal to the risk coefficient of each variable was taken as an integer value by rounding.) The total score was equal to the sum of all factors. Then the area under the receiver operating characteristics (AUC) curve was compared between high risk factors and scoring system. Finally, the scoring system was evaluated by the area under the curve (AUC) and the Hosmer-Lemeshow method in an independent cohort of 130 patients.Factors such as symptoms at presentation, tumor size, tumor blood supply, and tumor growth pattern were significant predictors of sporadic renal angiomyolipoma rupture in both the univariate and multivariate analyses; these predictors were included in the scoring system to predict sporadic renal angiomyolipoma rupture. There were no significant differences in AUCs between high risk factors and scoring system (z = 0.6434, P = .583, AUC = 0.913, and 0.903 for high risk factors and scoring system, respectively). The sporadic renal angiomyolipoma patients who scored >6 points were prone to rupture. AUROC of the scoring system in the validation set was 0.854(95%CI:0.779, 0.928). Using the Hosmer-Lemeshow method, the value of X was 2.916, P = .893, suggesting the scoring system fitted well.A scoring system based on clinical features is simple and effective in predicting sporadic angiolipoma rupture and hemorrhage. When the score is higher than 6 points, the probability of hamartoma rupture and hemorrhage is significantly increased and early intervention is needed.

Sporadic Angiomyolipomas Growth Kinetics While on Everolimus: Results of a Phase II Trial

PURPOSE

Everolimus decreases tumor volume of renal angiomyolipomas in patients with tuberous sclerosis. No prospective data are available regarding the effect of everolimus on the growth kinetics in patients with sporadic angiomyolipomas. We sought to determine the safety and efficacy of everolimus in the volumetric reduction of sporadic angiomyolipomas.

MATERIALS AND METHODS

This multi-institutional, prospective, phase II trial, enrolled patients with 3 cm or larger sporadic angiomyolipomas who were candidates for surgical resection or percutaneous angioembolization. Patients received 10 mg everolimus daily for 4 planned 28-day cycles. Response was defined as a 25% or greater volumetric reduction of patient angiomyolipoma. Baseline, 4, 6 and 12-month volumetric analyses were performed using magnetic resonance imaging. Everolimus was discontinued in those with less than 25% volumetric reduction after 4 cycles. Those with 25% or greater volumetric reduction received 2 additional cycles. The primary outcomes were the efficacy of everolimus in the volumetric reduction of angiomyolipomas by 25% or more, and the safety and tolerability of everolimus.

RESULTS

Overall 20 patients were enrolled at 5 centers. Of these patients 11 (55%) completed 4 cycles and 7 (35%) completed 6 cycles. Efficacy was demonstrated, with 10 of 18 (55.6%) patients exhibiting a 25% or greater reduction in tumor volume at 4 months (median 58.5%) and 10 of 14 (71.4%) patients exhibiting a 25% or greater reduction in tumor volume at 6 months (median 58.2%). Four (20%) patients were withdrawn due to protocol defined toxicities and 8 (40%) self-withdrew from the study due to side effects.

CONCLUSIONS

Everolimus was effective in causing volumetric reduction of angiomyolipomas by 25% or greater in most patients but was associated with a high rate of treatment discontinuation.

Limitations of Available Studies Prevent Reliable Comparison Between Tumour Ablation and Partial Nephrectomy for Patients with Localised Renal Masses: A Systematic Review from the European Association of Urology Renal Cell Cancer Guideline Panel

The European Association of Urology (EAU) Renal Cell Carcinoma (RCC) Guideline Panel performed a protocol-driven systematic review (SR) on thermal ablation (TA) compared with partial nephrectomy (PN) for T1N0M0 renal masses, in order to provide evidence to support its recommendations. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed, and only comparative studies published between 2000 and 2019 were included. Twenty-six nonrandomised comparative studies were included, recruiting a total of 167 80 patients. Risk of bias (RoB) assessment revealed high or uncertain RoB across all studies, with the vast majority being retrospective, observational studies with poorly matched controls and short follow-up. Limited data showed TA to be safe, but its long-term oncological effectiveness compared with PN remains uncertain. A quality assessment of pre-existing SRs (n=11) on the topic, using AMSTAR, revealed that all SRs had low confidence rating, with all but two SRs being rated critically low. In conclusion, the current data are inadequate to make any strong and clear conclusions regarding the clinical effectiveness of TA for treating T1N0M0 renal masses compared with PN. Therefore, TA may be cautiously considered an alternative to PN for T1N0M0 renal masses, but patients must be counselled carefully regarding the prevailing uncertainties. We recommend specific steps to improve the evidence base based on robust primary and secondary studies. PATIENT SUMMARY: In this report, we looked at the literature to determine the effectiveness of thermoablation (TA) in the treatment of small kidney tumours compared with surgical removal. We found that TA could cautiously be offered as an option due to many remaining uncertainties regarding its effectiveness.

Emergency retroperitoneal laparoscopic partial nephrectomy for ruptured renal angiomyolipomas: a retrospective single-center series of 15 cases

Background

To assess the safety, tumor control and renal function preservation of the emergency retroperitoneal laparoscopic partial nephrectomy (LPN) for ruptured renal angiomyolipoma (AML) and summarize our single-center initial experience.

Methods

We performed a retrospective analysis of 15 patients pathologically confirmed renal AML treated with emergency retroperitoneal LPN between January 2016 and May 2019. The patient demographics, operation time, blood loss, transfusion requirements, complications and other surgical parameters were analyzed. Follow-up was performed by serum creatinine and imaging modalities.

Results

Fifteen patients were performed with emergency LPN with the median age 41.6 years. The mean size of the renal AMLs was 7.8 cm. The mean size of the retroperitoneal hematomas was 8.5 cm. All the emergency surgeries were performed successfully without any conversion to nephrectomy or open surgery. The mean operative time was 101 min. The mean warm ischemia time was 28 min. The mean estimated blood loss was 311 ml. Five patients required intraoperative blood transfusion (33.3%, 5/15). The mean transfused RBC was 4 U (range 2-6 U), and the mean transfused plasma was 200 ml (range 200-400 ml). The mean drainage duration was 3 days (range 2–5 days). The mean postoperative hospitalization was 4.7 days. No patients experienced intraoperative complications. The mean serum creatine was slightly higher after surgery (53.1 vs. 55.9 μmol/L). One patient had postoperative perirenal fluid collection. No patients needed dialysis. No recurrence was observed in the patients at the median follow-up of 24.1 months.

Conclusions

Our initial experience shows that the emergency retroperitoneal LPN is a safe, minimally invasive procedure for emergency patients with ruptured renal AMLs. It could be considered as an effective alternative to renal artery embolization in selected emergency patients.

Outcomes and predictors of benign histology in patients undergoing robotic partial or radical nephrectomy for renal masses: a multicenter study

Introduction

Theaim of this study was to assess preoperative factors associated with benign histology in patients undergoing surgical removal of a renal mass and to analyze outcomes of robotic partial nephrectomy (PN) and radical nephrectomy (RN) for these masses.

Material and methods

Overall, 2,944 cases (543 benign and 2,401 malignant) who underwent robotic PN and RN between 2003–2018 at 10 institutions worldwide were included. The assessment of the predictors of benign histology was made at the final surgical pathology report. Descriptive statistics, Mann-Whitney U, Pearson’s χ², and logistic regression analysis were used.

Results

Patients in the benign group were mostly female (61 vs. 33%; p <0.001), with lower body mass index (BMI) (26.0 vs. 27.1 kg/m²; p <0.001). The benign group presented smaller tumor size (2.8 vs. 3.5 cm; p <0.001), R.E.N.A.L. score (6.0 vs. 7.0; p <0.001). There was a lower rate of hilar (11 vs.18%; p = 0.001), cT≥3 (1 vs. 4.5%; p <0.001) tumors in the benign group. There was a statistically significant higher rate of PN in the benign group (97 vs. 86%; p <0.001) as well as a statistically significant lower 30-day re-admission rate (2 vs. 5%; p = 0.081). Multivariable analysis showed male gender (OR: 0.52; p <0.001), BMI (OR: 0.95; p <0.001), and cT3a (OR: 0.22; p = 0.005) to be inversely associated to benign histology.

Conclusions

In 18% of cases, a benign histologic type was found. Only 3% of these tumors were treated with RN. Female gender, lower BMI, and higher T staging showed to be independent predictors of benign histology.

A new management strategy for renal angiomyolipomas: superselective arterial embolization in combination with radiofrequency ablation

Background

The present study analyzed the safety and efficacy of superselective arterial embolization (SAE) combined with radiofrequency ablation (RFA) to treat renal angiomyolipoma (RAML).

Methods

This retrospective study included the clinical data of 6 patients with RAML treated between March 2016 and October 2017. All patients underwent RFA treatment immediately after SAE guided by angio-computed tomography (angio-CT). The tumor size, renal function and complications, and time to recurrence were compared before and after treatment.

Results

The success rate of the SAE + RFA technique was 100%, and no serious complications were found during or after surgery. After treatment, the patients' symptoms, including low back pain and hematuria, were relieved. The pre-treatment creatinine level (55.6±11.0 µmol/L) did not differ significantly from the post-treatment creatinine level (68.2±13.7 µmol/L), which was measured 1 day after surgery (t=1.75, P=0.109). The mean follow-up time was 29.5±6.1 months. By the end of the follow-up period, the maximum diameter of the tumor was 3.1±0.6 cm, which was significantly smaller than the pre-treatment diameter of 5.9±1.01 cm (t=5.83, P<0.001). At 3 months after surgery, the maximum diameter of the tumor was reduced by 22-38% in all 6 patients. At the last follow-up examination, the maximum diameter of the tumor was reduced by 36-61%. Contrast-enhanced CT or magnetic resonance imaging scans showed that the enhanced part of the original lesion had disappeared, the renal parenchyma was full of even fat signals, and only one patient had new enhanced lesions at the site of the original lesions.

Conclusions

SAE combined with RFA is a safe and effective treatment for RAML, and its strengths qualify it to become a new treatment strategy for RAML.

Successful Utilization of a Live Donor Kidney with Angiomyolipoma

The gap between the kidney transplant recipient list and the number of organs available for transplantation continues to grow. Kidneys from living donors are a major source of high-quality organs. However, they commonly have benign conditions such as cysts and benign tumors that present as operative challenges. This case presents a donor kidney that had a benign angiomyolipoma. The kidney was donated in a standard, minimally invasive fashion. The tumor was then removed on the back table and transplanted without an issue. Both donor and recipient enjoyed a speedy recovery with no significant complications.

Germline mutation of TSC1 or TSC2 gene in Chinese patients with bilateral renal angiomyolipomas and mutation spectrum of Chinese TSC patients

The germline mutation of the TSC1/2 gene in bilateral renal angiomyolipomas is unclear. Meanwhile, the mutation spectrum of Chinese TSC patients has not been revealed. We recruited 78 patients diagnosed with bilateral renal AMLs. High-throughput sequencing was used to detect any variants in TSC1/2 genes. The results showed that 28.6% of patients diagnosed before 45 were with positive results of TSC1/2 test. The rate decreased to 14.3% for those with onset age over 45. For the 315 previously reported Chinese patients, TSC1 patients were more likely to be affected by nonsense mutations (51.1% vs. 20.7%, p<0.001) and had a significantly higher rate of family history than TSC2 patients (37.8% vs. 19.6%, p=0.0067). Moreover, exon8, 15, and 18 were the hotspot mutation regions for TSC1, and exon 29, 33 and 40 were the most common mutation regions for TSC2. Besides, Chinese TSC patients carried more TSC2 alterations (85.7% vs.76.2%, p<0.001), and were more likely to have a family history than those from TOSCA (22.2% vs. 13.9%, p<0.001). In conclusion, patients affected by bilateral renal AMLs should receive genetic testing of TSC ½ genes and Chinese TSC patients have relatively hotspot mutation regions, which are helpful to genetic counseling and clinical decision making.

How many surgically-treated angiomyolipomas are related to tuberous sclerosis complex? Insights from a retrospective multicenter study

BACKGROUND

Patients with TSC - related renal angiomyolipoma (AML) are eligible for targeted therapy with mTOR inhibitors, avoiding the morbidity of interventional management. Despite clinical criteria for TSC diagnosis have been defined, their use in routine clinical practice is likely suboptimal, leading to potential misclassification of TSC-related AML. The study aims to assess the proportion and characteristics of surgically-treated patients with putative sporadic AML that would have been re-classified as TSC-related.

METHODS

We retrospectively reviewed a prospectively collected multi-institutional database to select patients with suspected TSC-related AML among those undergoing surgery at three referral Centers over 11-years (2005-2015). Possible diagnosis of TSC was defined according to the 2012 International Tuberous Sclerosis Complex Consensus (ITSCC) criteria. The proportion and characteristics of patients with possible TSC-related AML (as compared to those of patients with sporadic AML) were considered the main study endpoints.

RESULTS

Overall, 132 patients were included. Of these, 10 (7.6%) were considered TSC-related. Most patients (84%) were female. Patients with TSC-related AML were likely to be younger (median age 53 vs. 56 years, P=0.29), symptomatic at diagnosis (70% vs. 21%, P=0.002), with slightly worse preoperative physical status (median ASA score 2 vs. 1, P=0.001) and bilateral disease (30% vs. 7.4%, P=0.04) as compared to patients with sporadic AML. Anatomic complexity and tumor size were also higher among TSC-related AMLs.

CONCLUSIONS

A non-negligible proportion of surgically-treated, putative sporadic AMLs were reclassified as potentially hereditary (TSC-related). As TSC patients may be treated with targeted therapies, our findings may increase urologists' awareness of TSC-related AML and prompt the design of future studies evaluating targeted diagnostic pathways for these patients.