Transarterial embolization for renal angiomyolipomas: A single centre experience in 79 patients

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.

Natural History and Management of Ultrasound-detected Small Renal Angiomyolipoma

Background

Recent advances in imaging methods increased the incidental detection of small renal angiomyolipoma (AML). However, guidelines for managing small AML are lacking, and decisions about imaging frequency and timing of intervention are made on an individual basis. This study aims to investigate the clinical behavior of small sporadic AML and propose an optimal follow-up strategy.

Methods

The study is a retrospective analysis of 168 individuals who had hyperechoic lesions, suggestive of AML detected during abdominal ultrasound as a part of their health checkup. The clinical information of the individuals, including tumor characteristics and renal function, was reviewed. Statistical analysis was performed to identify factors associated with tumor growth and renal function.

Results

Most AMLs were small (≤20 mm) and did not exhibit malignant characteristics. The tumors showed a slow growth rate, with a mean growth rate of 0.24 mm/year. Only a small proportion of cases (1.2%) required intervention due to significant enlargement. Factors such as tumor size and gender were not significantly associated with tumor growth rate or renal function. However, younger patients showed a higher tumor growth rate and a more pronounced decline in renal function.

Conclusion

Small sporadic AMLs have a slow growth rate and little risk of malignancy. Neither tumor size nor gender was predictive factors for tumor growth or renal function. Nevertheless, close monitoring of tumor growth and renal function is advised, particularly in younger patients. This study highlights the need for further research and guidelines to establish an optimal surveillance protocol for small AMLs.

Wunderlich Syndrome Managed with Angiomyolipoma Embolization - Renal Artery Anatomic Variant Augmenting Safe and Nephron-Sparing Intervention

Background

Wunderlich syndrome is an uncommon entity characterized by spontaneous, nontraumatic renal bleeding into the subcapsular and perirenal regions. The most frequent benign tumor, angiomyolipoma, is the most common cause of Wunderlich syndrome.

Case presentation

We report a case of Wunderlich syndrome in angiomyolipoma. Intratumoral pseudoaneurysm arising from feeders of an accessory renal artery supplying the lower pole of the kidney was selectively embolized. Rarely does a sporadic renal angiomyolipoma develop a giant pseudoaneurysm.

Conclusion

Transarterial embolization is imperative to control the bleeding or as a preventative measure to reduce the risk of intralesional pseudoaneurysm rupture. When vascular interventional facilities are unavailable, surgery may be necessary.

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.

Renal Arteriovenous (AV) Fistula after High-Grade Blunt Renal Trauma Caused by Traffic Accidents

PURPOSE

To report a series of three patients with traumatic renal AV fistulas after blunt renal laceration.

METHODS

We retrospectively analyzed the renal trauma cases treated in the Department of Urology of Salzburg University Clinic during a time period of 10 years concerning traumatic AV fistula formation and other clinical parameters.

RESULTS

In total, 3 cases of traumatic AV fistula formation were identified in 106 blunt renal trauma patients (2.8%), with a mean age of 39 (17-56) years. All renal traumas were classified as American Association for the Surgery of Trauma (AAST) grade IV. Two patients were primarily treated with ureteral stent; one was managed conservatively. All AV fistulas were diagnosed after a mean time of 7 (1-13) days. Two patients were symptomatic with gross hematuria, and the mean time between trauma and onset of symptoms was 11 (9-13) days. All cases were managed via coil embolization after a mean of 10 (8-13) days. Two patients received a second intervention after a mean of 18 (11-25) days. The mean AV fistula size was 18.7 (12-24) mm. Mean hemoglobin loss was 3.6 g/dL. One patient received one erythrocyte concentrate. Discharge was after a mean time of 13.3 (7-12) days, with the mean time of intensive care treatment being 2.3 (1-3) days.

CONCLUSIONS

Traumatic renal AV fistula is a rare but severe complication associated with higher-grade renal trauma. It can become evident through hematuria or blood loss several days after the initial trauma. The availability of coil embolization in a trauma center can help kidney preservation management.

Efficacy and safety of CalliSpheres® Microsphere transcatheter-arterial chemoembolization versus conventional TACE in treating renal angiomyolipoma patients

Objective

Transcatheter-arterial chemoembolization (TACE) is a well-established interventional technique for various tumor treatments, whereas its application in renal angiomyolipoma (RAML) is seldom reported. Conventional TACE (cTACE) with bleomycin-lipiodol emulsion is effective and tolerable for RAML treatment. In this study, we aimed to further explore the efficacy and safety between bleomycin-loaded CalliSpheres® microsphere TACE (CSM-TACE) and cTACE in treating RAML patients.

Methods

We retrospectively analyzed the data of 54 RAML patients treated by CSM-TACE (n = 17) or cTACE (n = 37). Data on tumor size, tumor volume reduction ratio, patient percentage with tumor size reduction, white blood cells (WBCs), creatinine (Cre) after treatment, complications, and adverse events were retrieved.

Results

Tumor size (88.66 vs. 81.19 cm3, P = 0.970), patient percentage with tumor size reduction (12 [70.59%] vs. 30 [81.08%], P = 0.486) after treatment, WBCs (P = 0.114), Cre (P = 0.659), and change in Cre after treatment (P = 0.947) were not significantly different between groups, whereas tumor volume reduction ratio was slightly lower in the CSM-TACE group than in the cTACE group (12 ± 34% vs. 32 ± 31%, P = 0.047). The most common postoperative complication was a post-embolization syndrome, including fever, nausea, and abdominal pain, which occurred in 9 (52.94%) and 14 (37.84%) patients from the CSM-TACE and cTACE groups, respectively (P = 0.347).

Conclusion

CSM-TACE is effective in and well tolerated by RAML patients, implying its potential as an alternative therapy.

Wunderlich Syndrome: Comprehensive Review of Diagnosis and Management

Wunderlich syndrome (WS), which was named after Carl Wunderlich, is a rare clinical syndrome characterized by an acute onset of spontaneous renal hemorrhage into the subcapsular, perirenal, and/or pararenal spaces, without a history of antecedent trauma. Patients may present with a multitude of symptoms ranging from nonspecific flank or abdominal pain to serious manifestations such as hypovolemic shock. The classic symptom complex of flank pain, a flank mass, and hypovolemic shock referred to as the Lenk triad is seen in a small subset of patients. Renal neoplasms such as angiomyolipomas and clear cell renal cell carcinomas that display an increased proclivity for hemorrhage and rupture contribute to approximately 60%-65% of all cases of WS. A plethora of renal vascular diseases (aneurysms or pseudoaneurysms, arteriovenous malformations or fistulae, renal vein thrombosis, and vasculitis syndromes) account for 20%-30% of cases of WS. Rare causes of WS include renal infections, cystic diseases, calculi, kidney failure, and coagulation disorders. Cross-sectional imaging modalities, particularly multiphasic CT or MRI, are integral to the detection, localization, and characterization of the underlying causes and facilitate optimal management. However, large-volume hemorrhage at patient presentation may obscure underlying causes, particularly neoplasms. If the initial CT or MRI examination shows no contributary causes, a dedicated CT or MRI follow-up study may be warranted to establish the cause of WS. Renal arterial embolization is a useful, minimally invasive, therapeutic option in patients who present with acute or life-threatening hemorrhage and can help avoid emergency radical surgery. Accurate diagnosis of the underlying cause of WS is critical for optimal patient treatment in emergency and nonemergency clinical settings. ^©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

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.

Selective arterial embolization of renal angiomyolipoma: comparing ethanol-lipiodol emulsion and polyvinyl alcohol particles as embolic agents

PURPOSE

To examine the effectiveness and safety of two embolic agents, an ethanol-lipiodol emulsion and polyvinyl alcohol (PVA) particles, for selective arterial embolization (SAE) of renal angiomyolipoma (AML).

METHODS

Retrospectively, we reviewed the medical records and imaging data of renal AML patients who received SAE in our hospitals between July 2007 and January 2018. Among those eligible for analysis were patients with complete medical information, preoperative and postoperative contrast-enhanced computed tomography scans, and follow-up data. An ethanol-lipiodol emulsion was used to embolize 15 AMLs, and PVA particles were used to embolize 16 AMLs. We compared the tumor responses and adverse events between the two embolization-agent groups.

RESULTS

After embolization, no significant differences were observed in the shrinkage rates: 34.2% ± 3.4% for the ethanol-lipiodol emulsion group and 26.3% ± 3.0% for the PVA particles group (P = 0.090). Minor post-embolization complications were also similar between the groups, and there were no severe adverse events. The length of hospital stay after SAE was 2.5 ± 0.5 days for the ethanol-lipiodol emulsion group and 1.9 ± 0.5 days for the PVA particles group and was not significantly different (P = 0.425).

CONCLUSION

The results showed that SAE with ethanol-lipiodol emulsion or PVA particles was safe and efficient in decreasing tumor size and controlling renal AML hemorrhage.

Efficacy and safety of selective renal arterial embolization in renal angiomyolipoma: a prospective single-center study

Background

Preventing acute complication of renal angiomyolipoma (AML), preserving renal parenchyma, and improving long-term renal function are the treatment targets of renal angiomyolipoma. Treatment should be considered for symptomatic lesions or those who are at risk of complications, especially bleeding symptoms, which are linked to tumor size, angiogenic component grade, and presence of tuberous sclerosis complex (TSC). Selective arterial embolization (SAE) has become the new norm for preventive or emergency treatment of renal AMLs with minimally invasive selective targeting of small arterial feeders, we aimed to assess the efficacy and safety of selective renal arterial embolization (SAE) in the management of complicated renal angiomyolipoma and to detect the predictors of prophylactic SAE in cases of non-complicated AML.

Results

Bleeding symptoms were significantly more frequent in patients with TSC-associated renal AMLs (C = 0.333 and p = 0.036) and patients with intra-lesional aneurysm > 3 mm (C = 0.387 and p = 0.013). Overall success rate: thirty-three (91.7%) renal AMLs were successfully embolized with no recurrence. While three (8.3%) renal AMLs were not; one (2.8%) renal AML was not embolized due to technical failure and two (5.5%) renal AMLs showed recurrence. Primary (technical) success rate: thirty-three (86.9%) successful embolization, five (13.1%) arteriographies were done with failed embolization. The maximum diameter and volume of the lesions after SAE showed statistically significant reduction (z = 4.25 and p < 0.001).

Conclusions

SAE is an effective and safe technique to manage renal AMLs preoperatively or in an emergency. TSC-associated lesions, and intra-lesional aneurysms (aneurysms > 3 mm in diameter) were significantly more associated with bleeding symptoms, considering them significant predictors for prophylactic SAE in non-complicated AML.

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

Renal hematuric angiomyolipomas embolization: three cases and literature review

We report three cases of hemorrhagic renal angiomyolipoma successfully treated using embolization. Endovascular management of this complication is highlighted.

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.

Radiologic and clinical results of transarterial ethanol embolization for renal angiomyolipoma

OBJECTIVE

We sought to determine the efficacy and safety of selective arterial embolization for renal angiomyolipoma (AML) using ethanol alone or ethanol with additional embolic materials and to analyze the factors influencing safety and efficacy.

METHODS

One hundred nineteen AMLs treated with embolization were included retrospectively during a 15-year period. Technical, radiologic, and clinical success were recorded and risk factor analysis was performed. Complications on follow-up images, post-embolization syndrome (PES), major complications, and changes in renal function were also evaluated.

RESULTS

Technical success was achieved in 106 of 119 tumors. Tumor size significantly decreased after treatment (reduction rate: 55%). Significant risk factors for tumor reduction included tumor enhancement on preprocedural CT and residual tumor staining. Radiologic success was achieved in 114 of 119 tumors (risk factor: residual tumor staining), and clinical success was achieved in 22 of 23 patients. Complications on follow-up images occurred in 40 of 119 tumors, and PES occurred in 53 of 104 patients. No major complications occurred. There were no cases of renal function impairment.

CONCLUSION

Selective transarterial embolization using ethanol alone or ethanol with additional embolic materials reduced AML size, alleviated symptoms, and can be performed safely without permanent impairment.

KEY POINTS

• Percutaneous transarterial ethanol embolization reduces AML size and alleviates symptoms. • Embolization can be performed safely without permanent impairment of renal function.

Evidence-based protocol-led management of renal angiomyolipoma: A review of literature

Renal angiomyolipomas (R-AMLs) are rare benign tumors, which occur sporadically and in association with genetic conditions such as tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM). The key clinical concern is life-threatening hemorrhage. There is uncertainty about the optimal management strategy for patients with R-AMLs. We aim to review the evidence and provide a protocolled approach for the management of R-AMLs. A literature search of R-AML was conducted using MEDLINE and EMBASE for articles published between January 1990 and March 2020. Patient with TSC and sporadic cases were included. Treatment strategies, including active surveillance, surgery, selective arterial embolization (SAE), ablation, and systemic therapies, were reviewed. Outcomes from contemporary case series of active surveillance, surgery, and SAE were collated. There were no randomized controlled trials on this topic. The retrospective case series reviewed showed that many R-AMLs can be managed safely with active surveillance. Tumor size is the most important predictor of bleeding, and other factors such as rate of growth, women of child-bearing age, aneurysm size, and symptoms should be considered when deciding on prophylactic treatment. There is limited evidence for the traditional 4-cm cutoff for treatment, which may lead to overtreatment. The primary intervention options are SAE and surgery; whereas SAE is a less invasive option, nephron sparing surgery offers a lower risk of recurrence. Both appear to have similar morbidity, and the current evidence does not recommend one over the other in most cases. Thermal ablation has promising results but has only been trialed in small case series. Patients with TSC can be offered mammalian target of rapamycin inhibitors of which everolimus appears to cause the greatest shrinkage of tumors with an acceptable side-effect profile. R-AMLs should be assessed for their risk of bleeding. Low-risk tumors should be treated with active surveillance. High-risk tumors should be treated with SAE or surgery. Systemic treatments are the first-line of treatment for patients with TSC to preserve renal parenchyma.

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.

Renal angiomyolipomatosis and bleeding aneurysms in a tuberous sclerosis context: selective artery embolization in a girl with end-stage renal failure

Recent developments in endovascular radiological techniques and devices have rendered embolization a major therapeutic option prior to surgery in many renal vascular or neoplastic diseases. A 19-yearold female patient, with a diagnosis of tuberous sclerosis complex (TSC) in childhood, was admitted with severe anemia. Polycystic kidney disease in end-stage renal failure appeared four years before and the patient has been undergoing peritoneal dialysis. The patient's medical history also included bilateral renal angiomyolipomas (AMLs). One year earlier, a unilateral endovascular embolization was performed to repair a bleeding aneurysm at the right renal upper pole. A second bilateral ruptured renal aneurysm was diagnosed at admission. To continue with peritoneal dialysis and prevent intrarenal hemorrhage and intraperitonal bleeding, an urgent bilateral renal AE was performed. Two months later she underwent a bilateral retroperitoneal nephrectomy. The posterior surgical approach, preserved the peritoneal surface area and adequate conditions to continue dialysis. At histology, bilateral AMLs were confirmed and a renal cell carcinoma of the right kidney was concurrently discovered. She undergoes continuous peritoneal dialysis. Urgent selective renal AE represents a feasible treatment for bilateral AML bleeding. It is safe and feasible before performing nephrectomy in patients with end-stage renal failure.

Selective Arterial Embolizations of Renal Angiomyolipomas Using 96% Ethanol: A Case Series of 5 Patients

Angiomyolipomas are rare benign tumors of the kidneys, with a risk of spontaneous hemorrhage including severe retroperitoneal bleedings. In this study, we report clinical outcomes of 5 patients who underwent 8 embolization sessions using 96% ethanol, as there is scarce data using this embolic agent for this indication. The primary angiographic success could be achieved in all but 1 lesion, which was not accessible due to vasospasm of the supplying vessel. Therapeutic success could be demonstrated in all treated cases for which follow-up imaging was available (n = 3). In 1 complex patient, a mildly reduced renal function, as well as a new onset of arterial hypertension was detected after treatment. Nontarget embolization of vital kidney tissue was demonstrated in another patient; it remained asymptomatic. Embolization therapy using 96% ethanol is an optional method to treat renal angiomyolipomas.

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Objectives: To present a patient material of renal angiomyolipoma (AML) with focus on the risk of bleeding during active surveillance (AS).Methods: Medical records, 1999-2014, were studied and 98 patients (80 female, 18 men) with renal AML were identified. Eleven patients had tuberous sclerosis complex (TSC). Mean age was 54 (13-89) years.Results: Sixty patients (61%) were asymptomatic at presentation, 33 (34%) presented with flank pain and five (5%) with hematuria. Retroperitoneal bleeding or hematuria was diagnosed in 20 patients with a mean AML size of 74 mm (25-200 mm). Twenty-one patients were treated with angioembolization at time of diagnosis and 25 had surgery. Forty-five patients with sporadic AML (mean size 34 mm) and six with TSC (mean size 120 mm) were selected for AS. Only one patient with sporadic AML (46 mm) had a bleeding, whereas two of the six TSC patients had bleedings from three kidneys (AML 70-300 mm). In 25 patients (49%), the AML-size increased with 2.7 mm/year in sporadic and 5.4 mm/year in TSC-associated AML. Thirteen patients were treated with AE (including all six TSC-patients) and five with surgery in 22 kidneys due to AML-size in 16, bleeding in four and suspicion of cancer in two.Conclusion: Bleeding occurred in 20% of AML at presentation. In patients selected for AS, we found a very low risk of bleeding in sporadic AML justifying our cut off size of 50 mm to trigger intervention. In TSC-associated AML individually tailored follow-up is needed due to a higher intervention rate.

Optimal Ethanol-Ethiodol Emulsion Ratio in Renal Angiomyolipoma Embolization: A Question that Remains Unanswered

The authors, a case series of five cases of angiomyolipomas (AMLs), embolized with a high ethanol:ethiodol ratio of 6:1 emulsion at a single tertiary center. Although ethanol as an embolic agent has been reported in the past for AMLs, much higher ratios of ethiodol were used, and administration is typically performed using an occlusion balloon. Two of the patients were incidentally diagnosed, while the other four were diagnosed after hematuria workup. Of the five patients, only one developed postembolization syndrome. Otherwise, no complications, recurrences, or reinterventions are reported. Our higher ratio seems to allow for adequate radio-opacity of the emulsion with minimal negative dilution effect.

Renal function, complications, and outcomes of a reduction in tumor size after transarterial embolization for renal angiomyolipomas: a meta-analysis

OBJECTIVE

The present study aimed to evaluate renal function, complications, and changes in tumor size after transarterial embolization for patients with renal angiomyolipomas.

METHODS

We performed a meta-analysis of transarterial embolization in patients with renal angiomyolipomas from January 1994 to April 2018. Endpoints of interest were the estimated glomerular filtration rate, serum creatinine levels, blood urea nitrogen levels, complications, and reduction of tumors.

RESULTS

A total of 30 studies comprising 653 patients were included. A total of 32.0% of patients were treated by urgent transarterial embolization for spontaneous ruptured renal angiomyolipomas. Other patients sought to relieve symptoms or received embolism prophylactically. The estimated glomerular filtration rate showed no significant difference between before and after embolization. In 363 patients with data on complications, post-embolization syndrome occurred most frequently (54.0%). Only 16 (4.4%) patients had major complications. The diameter of sporadic angiomyolipomas was reduced by a mean of 2.09 cm (95% confidence interval [CI], 0.73-3.45 cm; I2 = 29.3%) and they were reduced in size by 30.0% (95% CI, 16.0%-44.0%; I2 = 27.9%).

CONCLUSIONS

Transarterial embolization of renal angiomyolipomas affects renal function preservation, with a low complication rate. Transarterial embolization is useful for sporadic and tuberous sclerosis complex-related angiomyolipomas.

Tuberous sclerosis complex: new insights into clinical and therapeutic approach

Tuberous sclerosis complex (TSC) is a complex disease with many different clinical manifestations. Despite the common opinion that TSC is a rare condition, with a mean incidence of 1/6000 live births and a prevalence of 1/20,000, it is increasingly evident that in reality this is not true. Its clinical sequelae span a range of multiple organ systems, in particular the central nervous system, kidneys, skin and lungs. The management of TSC patients is heavily burdensome in terms of time and healthcare costs both for the families and for the healthcare system. Management options include conservative approaches, surgery, pharmacotherapy with mammalian target of rapamycin inhibitors and recently proposed options such as therapy with anti-EGFR antibody and ultrasound-guided percutaneous microwaves. So far, however, no systematically accepted strategy has been found that is both clinically and economically efficient. Thus, decisions are tailored to patients' characteristics, resource availability and clinical and technical expertise of each single center. This paper reviews the pathophysiology and the clinical (diagnostic-therapeutic) management of TSC.

Prophylactic selective arterial embolization for renal angiomyolipomas: efficacy and evaluation of predictive factors of significant shrinkage

PURPOSE

To evaluate the efficacy of prophylactic selective arterial embolization (SAE) of angiomyolipomas (AMLs) and to find out predictive factors of significant shrinkage of AMLs after SAE.

METHODS

Patients receiving prophylactic SAE for renal AMLs with complete medical records were included. The changes of the size, urine erythrocyte counts, and serum creatinine of all patients pre- and post-embolization were assessed. Demographic data, symptoms, the background of tuberous sclerosis complex (TSC), aneurysms, enhancement features, initial tumor sizes, and serum creatinine pre-embolization were estimated as predictive factors of significant shrinkage in size.

RESULTS

Forty-five patients receiving prophylactic SAE for AMLs successfully in our center were included with median follow-up of 14.0 months (interquartile range 6.5-40.5). Mean size of AMLs decreased from 10.7 ± 6.2 to 8.3 ± 5.9 cm by 23.4% ± 20.6% at the latest follow-up (P < 0.001). Urine erythrocytes decreased significantly after SAE (11.1 [interquartile range 5.7-23.2] vs. 6.4 [interquartile range 2.7-13.4], P < 0.001). In addition, there was no significant change between the serum creatinine before and after embolization (81.8 ± 14.9 mmol/L vs. 83.6 ± 17.1 mmol/L, P = 0.224). Of the variables mentioned above, only the enhanced area of AMLs before SAE was statistically significant between the groups with and without significant shrinkage (P < 0.001). In multiv-ariate analysis, enhanced area < 25% (AOR = 0.015, 95% CI 0.001-0.367) and having the background of TSC (AOR = 0.056, 95% CI 0.004-0.799) were identified as predictive factors of significant shrinkage of the tumors.

CONCLUSIONS

Prophylactic SAE is effective in reducing the size of renal AMLs and decreasing urine erythrocytes with preservation of renal function. Significant shrinkage of AMLs after SAE is modulated by the enhanced area and the background of TSC.

Are We Overtreating Renal Angiomyolipoma: A Review of the Literature and Assessment of Contemporary Management and Follow-Up Strategies

Renal angiomyolipoma (AML) are benign tumours composed of fat, muscle, and disorganised blood vessels. Historic treatment algorithms for sporadic AML based on size fail to consider additional risk factors such as tumour vascularity and pseudoaneurysm formation. As AML is now predominantly incidental, rupture is rare and its mortality low. The recent publication of the largest longitudinal series to date also suggest that growth is uncommon, challenging existing surveillance paradigms. The evidence assessing treatment strategies in AML are reviewed, with particular emphasis on incidental sporadic AML. The relative merits of various AML treatments are discussed, and areas of clinical uncertainty highlighted.

The Risks of Renal Angiomyolipoma: Reviewing the Evidence

Renal angiomyolipoma (RAML), though a rare benign tumor, may impose a significant morbidity or even mortality due to its unique characteristics and the complications subsequent to its treatment. The classic tumor variant is composed of smooth muscular, vascular, and fatty components. The most straightforward diagnosis is when the fat component is abundant and gives a characteristic appearance on different imaging studies. In fat-poor lesions, however, the diagnosis is difficult and presumed a renal cell carcinoma. Yet, some variants of RAML, though rare, express an aggressive behavior leading to metastasis and mortality. The challenge lies in the early detection of benign variants and identifying aggressive lesions for proper management. Another challenge is when the vascular tissue component predominates and poses a risk of hemorrhage that may extend to the retroperitoneum in a massive life-threatening condition. The predicament here is to identify the characteristics of tumors at risk of bleeding and provide a prophylactic treatment. According to the clinical presentation, different treatment modalities, prophylactic or therapeutic, are available that span the spectrum of observation, embolization, or surgery. Renal impairment may result from extensive tumor burden or as a complication of the management itself. Improvement of diagnostic techniques, super-selective embolization, nephron-sparing surgery, and late treatment with the mammalian target of rapamycin inhibitors have provided more effective and safe management strategies. In this review, we examine the evidence pertaining to the risks imposed by RAML to the patients and identify merits and hazards associated with different treatment modalities.

Management of iatrogenic renal arteriovenous fistula and renal arterial pseudoaneurysm by transarterial embolization: A single center analysis and outcomes

The purpose of this study was to evaluate the efficacy and safety of transarterial embolization (TAE) for iatrogenic renal arterial pseudoaneurysm and arteriovenous fistula at our center.Our retrospective analysis included 27 patients who received TAE for iatrogenic renal arterial pseudoaneurysm and arteriovenous fistula between January 2006 and January 2016. Data on demographics, type of minimally invasive renal procedures, clinical manifestation, imaging features, embolization procedure, and perioperative details were collected. The technical and clinical success rates were analyzed. Furthermore, the changes in serum creatinine and eGFR before and after embolization were recorded and compared by t test.The median time between iatrogenic renal injury and TAE was 3 days (range, 0-110 days), with most patients (24/27, 88.9%) receiving TAE within 14 days. Only 1 patient was diagnosed with renal artery pseudoaneurysm 110 days after laproscopic partial nephrectomy. The technical and clinical success rates were 100% and 96.3%, respectively, with 1 patient requiring a second embolotherapy at the third postoperative day. No other patient required additional endovascular or surgical intervention due to recurrent hemorrhage. The mean serum creatinine before TAE was 92.8 ± 25.3 μmol/L and after TAE, 96.1 ± 27.7 μmol/L (P = .095). The eGFR of pre- and postembolization was 75.2 ± 26.5 mL/min/1.73 m and 72.5 ± 26.2 mL/min/1.73 m (P = .16). No severe complications were observed during follow-up.This retrospective review demonstrated that TAE for the treatment of iatrogenic renal artery pseudoaneurysm and/or arteriovenous fistula was safe and associated with high technical and clinical success rate.