Management of renal angiomyolipoma by selective arterial embolization

Embolization of hemorrhagic renal angiomyolipoma complicated by arteriovenous shunting: A case report

Arteriovenous shunting associated with angiomyolipoma is an unusual entity, which carries important implications to embolization approach. We present a distinctive case involving a 41-year-old woman who presented with retroperitoneal hemorrhage relating to renal angiomyolipoma. During angiography for urgent embolization, a complex vascular supply with arteriovenous shunting was encountered. Superselective embolization using alcohol or small particles is the standard approach to definitive treatment of symptomatic angiomyolipoma; however; their use is precluded in the setting of arteriovenous shunt hemodynamics. In this case, a 2-step approach was employed by which the initial hemorrhage was treated with proximal embolization using large gelatin foam and metallic coils. This resulted in decreased flow through the arteriovenous shunt, allowing the use high viscosity ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide for definitive treatment.

Outcomes of angioembolization and nephrectomy for renal angiomyolipoma associated with tuberous sclerosis complex: a real-world US national study

OBJECTIVE

To examine outcomes of clinical procedures for renal angiomyolipoma associated with tuberous sclerosis complex (TSC) based on US national health claims databases.

METHODS

This retrospective cohort study selected two cohorts of TSC patients, who underwent either embolization or nephrectomy (either partial or complete) for renal angiomyolipoma in the years from 2000 through 2011. Based on claims diagnosis codes, we estimated the prevalence rates of 10 angiomyolipoma-related conditions and 50 embolization- or nephrectomy-related conditions in the pre- and post-baseline periods respectively, and made cross-year and cross-period comparison of these rates with repeated measures analysis methods.

RESULTS

The embolization cohort (N = 4280) and the nephrectomy cohort (N = 3842) had mean baseline ages of 50.7 and 51.7 years with 52.5% and 51.3% males, respectively. After the intervention, the embolization cohort had statistically significant reductions (all p < .05) in gross hematuria (-27.7%), retroperitoneal hemorrhage (-8.4%), and abdominal mass (-6.9%), and increases in hypertension (15.5%), renal mass or unspecified disorder of kidney and ureter (13.8%), anemia (5.1%), and renal insufficiency (3.3%). Similarly, the nephrectomy cohort saw statistically significant reductions (all p < .05) in gross hematuria (-30.6%), flank pain (-7.5%), and abdominal mass (-6.4%), but increases in hypertension (11.9%), renal insufficiency (10.4%), and anemia (7.6%). Embolization was associated with post-procedure increases in renal mass or unspecified kidney/ureter disorder (13.9%), other disorders of kidney and ureter (3.4%), non-acute renal insufficiency (3.1%), flank pain (3.7%), renal insufficiency (3.2%), etc. (all p < .05). Nephrectomy was associated with post-procedure increases in postoperative ileus (5.3%), pain and headache (4.8%), paralytic ileus (3.6%), etc. (all p < .05).

CONCLUSIONS

Both embolization and nephrectomy were effective, but associated with increases in certain angiomyolipoma-related conditions. Further, the embolization effect on gross hematuria, retroperitoneal hemorrhage, and abdominal mass might subside after the intervention year.

Selective arterial embolization of angiomyolipomas: a comparison of smaller and larger embolic agents

PURPOSE

Selective transarterial embolization for renal angiomyolipomas is effective in preventing or limiting hemorrhage and preserving normal parenchyma. Data are insufficient regarding the safety and efficacy of embolic agents. We compared transarterial embolization of angiomyolipomas using embolic agents of different sizes.

MATERIALS AND METHODS

We performed a retrospective review of all transarterial angiomyolipoma embolizations from 1999 to 2010, and evaluated demographics, procedural data, embolization response and outcomes comparing smaller (less than 150 microns) and larger (more than 150 microns) embolic agents.

RESULTS

Overall 48 patients underwent 66 embolization procedures for 72 angiomyolipomas. Smaller agents were used more commonly (58%). Age, gender, indications, pre-embolization angiomyolipoma size and prevalence of tuberous sclerosis were similar between the groups. Angiomyolipomas decreased a mean±SD 25%±18% after embolization with no differences between the groups (p=0.24). There were 10 angiomyolipomas that required 14 repeat embolizations (median 14 months). Repeat embolization of the same mass was almost sixfold more likely in those embolized with smaller agents (OR 5.88, 95% CI 1.64-20.8, p=0.002). Complications were similar between the groups, although 2 of 3 patients with acute respiratory distress underwent embolization with smaller agents. Patients with tuberous sclerosis had similar angiomyolipoma size, decrease in angiomyolipoma size, followup, complications and need for repeat embolization. Practice patterns changed regarding embolization agent size during the study period.

CONCLUSIONS

Angioembolization with larger embolic agents is associated with higher long-term efficacy compared to smaller agents. Due to concerns for serious pulmonary complications, we no longer use agents smaller than 150 microns. Prospective studies are necessary to evaluate the optimal embolization technique to achieve durable outcomes without increasing patient morbidity.

Embolization of giant renal angiomyolipomas: technique and results

PURPOSE

To evaluate the efficacy and safety of prophylactic embolization of angiomyolipomas (AMLs) larger than 10 cm.

MATERIALS AND METHODS

Sixteen patients (mean age, 41.2 years; 14 women and two men) underwent embolization for 23 AMLs larger than 10 cm. All lesions were embolized by using microcatheters with ethanol and ethiodized oil mixed to a ratio of 7(ethanol) to 3(ethiodized oil). Data collected included pre- and posttreatment AML size, creatinine level, technical success, volume of embolic material used, clinical success, and complications.

RESULTS

The mean AML size before treatment was 15 cm (range, 10-25 cm). Ten of the 16 patients (62%) had all their AMLs treated in one session, whereas six (38%) required multiple sessions. A mean volume of 8.6 mL of the ethanol-ethiodized oil mixture (range, 2-20 mL) was administered per lesion. Patients were followed up for a mean of 29 months (range, 1-80 months). No patient had an increase of 0.2 mg/dL (17.7 mumol/L) or greater in mean serum creatinine level during the follow-up period. Two of the 16 patients (12%) required repeat embolization due to AML regrowth (n = 1) or reperfusion (n = 1) seen at surveillance imaging. One of the 16 patients (6.2%) had an AML hemorrhage 59 months after AML embolization.

CONCLUSIONS

Embolization of giant renal AMLs to decrease the risk of bleeding can be done safely without loss of renal function. Although recurrence was infrequent, additional treatment may be necessary and giant renal AMLs should be followed up with serial imaging studies.

The efficacy and outcomes of urgent superselective transcatheter arterial embolization of patients with ruptured renal angiomyolipomas

BACKGROUND

To assess the efficacy and outcomes of urgent superselective transcatheter arterial embolization for emergency patients with ruptured renal angiomyolipomas.

METHODS

During a 49-month period, all emergency patients with ruptured angiomyolipomas that underwent urgent superselective transcatheter arterial embolization within the first 24 hours of admission were enrolled in this study. In each case, clinical presentation, trauma history, success or failure of embolization, presence of postembolization syndrome, and the necessity of subsequent emergency surgery of nephron-sparing surgery, and partial or total nephrectomy were recorded and analyzed.

RESULTS

The sample population consisted of seven female patients with ruptured angiomyolipomas; mean age was 48 years. The initial presenting symptoms were flank pain (n = 7), hematuria (n = 5), and lower hematocrit (Hb <10; n = 7). All individuals had received blood transfusion before the embolization. Two were traffic crash victims admitted in shock. Successful embolization was achieved in all cases; however, postembolization syndrome was noted in four. There was no requirement for emergent surgery after embolization.

CONCLUSIONS

Urgent superselective transcatheter arterial embolization was an effective treatment for our sample of emergency patients with ruptured renal angiomyolipomas where conservative supportive treatments had failed. There was no need of emergency surgery after embolization.

Pseudoaneurysm after spontaneous rupture of renal angiomyolipoma in tuberous sclerosis: successful treatment with percutaneous thrombin injection

We report a case of a large perinephric pseudoaneurysm due to spontaneous rupture of renal angiomyolipoma, occluded by percutaneous thrombin injection under ultrasound guidance in a young woman affected by tuberous sclerosis.

Renal angiomyolipomata

Renal angiomyolipomata can exist as an imaging curiosity or represent a life-threatening condition. There are likely over 10 million people world-wide who have a renal angiomyolipomata and approximately one tenth of these people also have tuberous sclerosis complex. The optimum treatment of angiomyolipomata is focused on sparing renal tissue and has included no intervention, both total and partial nephrectomy, and embolization. As basic science investigation into the biology of angiomyolipomata progresses, there is even hope for successful drug therapy. Because these renal lesions can be associated with other organ system dysfunction, a number of medical specialists become involved in the care of affected patients. The purpose of this article is to update the nephrologist on the molecular understanding of renal angiomyolipomata and for the possibilities of pharmacologic therapy in the future.

Estrogen receptor is significantly associated with the epithelioid variants of renal angiomyolipoma: A clinicopathological and immunohistochemical study of 67 cases

Perivascular epithelioid cells (PEC) in angiomyolipoma (AML) were recently proposed to be its most common progenitor cells. Histologically, triphasic components were present in various proportions, but were overwhelmingly myogenic in epithelioid variants of AML. Despite histological discrimination, the immunophenotypic profiles between triphasic and epithelioid AML have never been compared. The aim of the present study was to clarify the identity of PEC by using immunoreactivity to estrogen receptor (ER), progesterone receptor (PR), bcl-2 and placenta alkaline phosphatase (PLAP), and to use this information to compare triphasic and epithelioid AML. A total of 33 out of 67 cases of renal angiomyolipoma that underwent surgery were reviewed over the period 1998-2003. Two cases were associated with tuberous sclerosis. Ten patients had other malignant tumors, and three patients had a nodal extension. Immunohistochemistry showed that bcl-2 (59.4%), PLAP (46.9%), HMB-45 (100%) was predominantly localized around vessels. The stem cell markers were absolutely negative in all AML types. The estrogen receptors were positive in 14 cases (42.4%) and the progesterone receptors were positive in five cases. Bcl-2 and both female sex hormone receptors were significantly more frequent in the epithelioid variant of AML than in the triphasic type. Perivascular epithelioid cells express bcl-2, ER, PR and PLAP, and ER could be partly associated with myogenic proliferation.

Spontaneous extraperitoneal haemorrhage: Computed tomography diagnosis and treatment by selective arterial embolization

Four cases of extraperitoneal haemorrhage occurring in the setting of anticoagulation or coagulopathy are presented. Treatment of this condition has traditionally consisted of reversal of anticoagulation and supportive therapy. Diagnosis was made on contrast-enhanced computed tomography. The finding of active contrast extravasation was found to be a factor predictive of failure of conservative therapy and, therefore, an indication for angiography and embolization. In all four cases presented in the present paper, the bleeding vessel(s) were identified and significant active bleeding arrested by transcatheter embolization.

Reduction of postembolization syndrome after ablation of renal angiomyolipoma

Approximately 75% of patients with tuberous sclerosis complex develop renal angiomyolipomas. These hamartomatous lesions distort and damage renal parenchyma and can lead to hemorrhage. To reduce the risk of hemorrhage, transarterial embolization is used to necrose the angiomyolipoma while sparing normal renal tissue. Although an effective renal-sparing procedure, embolization most often is associated with an inflammatory response that causes significant fever and pain that can last for several days despite the use of acetaminophen. Reported cases show that 49 of 55 patients who underwent embolization developed this syndrome. The use of such nonsteroidal anti-inflammatory drugs as aspirin is contraindicated because of their adverse effects on platelet function. To reduce pain and fever associated with postembolization syndrome (PES), we changed our clinical management of patients postembolization to include a tapering dose of prednisone over a 2-week period. Nine patients underwent this pharmacological intervention, and one patient abstained. All patients were monitored for pain and fever. Only two patients treated with steroids developed fever, which was assuaged with acetaminophen, and no patient reported pain. The tapering dose of prednisone was well tolerated, and there were no postprocedure infections. The use of a short-term tapering dose of prednisone appeared to reduce PES compared with the reported literature and improved patient comfort.

Nephron-sparing surgery for renal angiomyolipoma

INTRODUCTION

Renal angiomyolipoma (RAML) is a benign tumor composed of varying amounts of mature adipose tissue, smooth muscle and thick-walled blood vessels. RAML tend to grow over time requiring active intervention due to serious associated complications, such as hemorrhage and pain. Although RAML is an ideal tumor for organ preservation, data concerning efficacy of nephron-sparing surgery (NSS) are sparse. The aim of the study was to evaluate the efficacy of NSS in RAML with regard to renal function, tumor recurrence and surgical feasibility.

PATIENTS AND METHODS

Charts of patients with pathologically confirmed RAML were reviewed and data recorded: tumor size, associated symptoms, intraoperative blood loss, serum creatinine, follow-up data with regard to tumor recurrence and long-term renal function. A total of 28 patients were identified with RAML who underwent NSS because of tumor size > 4 cm, pain and/or to rule out malignancy due to radiographic features of uncertain interpretation.

RESULTS

The median follow-up of all patients is 58 (3-114) months; median age was 55.6 (34-78) years, 24 patients were women, 4 patients were men. None of the patients developed a local recurrence. Median size of enucleated tumors was 5.5 (2.5-15) cm; indication for NSS was symptomatic tumor with hemorrhage in 4 patients (16%), prophylaxis of hemorrhage in 5 patients (20%) and radiographic features suspicious for malignancy in 16 patients (64%). In those cases, unenhanced and enhanced CT scans exhibit a hyperdense and a hypodense lesion as compared to the adjacent normal renal cortex, respectively. There were no intraoperative complications, median blood loss was 320 (50-1200) ml, none of the patients required blood transfusions. Post-operative course was uneventful in 26 patients (96%), 2 patients (7.1%) developed a urinary fistula managed by an endoluminal stent. Pre-operative serum creatinine was 0.9 (0.7-1.3) mg/dl, post-operative creatinine was 1.23 (0.7-1.5) mg/dl and serum creatinine at last follow-up was 0.95 (0.7-1.2) mg/dl.

CONCLUSIONS

NSS can be performed with a high success rate in RAML when surgical management is indicated. Long-term follow-up reveals no local tumor recurrences and stable renal function even in patients with a solitary kidney.

Management of renal angiomyolipoma in complex clinical situations

Renal angiomyolipoma (AML) is associated with complex clinical situations such as tumour in a solitary kidney, bilateral, large or multicentric tumours or those associated with tuberous sclerosis (TS) or pregnancy. Management in these situations may be challenging. Fifteen patients (20 kidneys) were admitted with symptomatic AML over last 10 years. Eleven patients had one or the other complicating factor. Ten patients had a tumour of >10 cm, 4 had TS, 5 had multiple and bilateral tumours, 1 patient was pregnant and 1 had a solitary functioning kidney. With the newer imaging modalities correct diagnosis was possible in 12 cases and renal cell carcinoma (RCC) was suspected in 3 cases. Selective angioembolization (SAE) was done in 3 patients, which successfully controlled bleeding in all. Nephron-sparing surgery (NSS) was performed in 5 patients. Total nephrectomy was done in 4 cases, in 3 due to suspicion of RCC and in 1 due to extensive involvement of the kidney. Three patients with multiple and bilateral tumours were chosen for conservative treatment and none developed recurrence of bleeding on strict follow-up. In a pregnant patient, bleeding was successfully controlled with angioembolization. However, 1 patient with a solitary functioning kidney with large-sized tumour (20 x 18 cm) underwent NSS. In conclusion, the basis of management of AML is preservation of renal tissue, which can be effectively achieved with SAE or NSS. In a solitary functioning kidney, NSS or SAE is the ideal treatment, if feasible. The patients in the TS group are usually more complicated and require life-long follow-up after initial management with NSS or SAE. Pregnant AML patients can be safely managed with SAE. Conservative treatment without any intervention and regular follow-up may be more helpful in some patients with multiple, bilateral extensive tumours.