Long-term outcome of transcatheter embolization of renal angiomyolipomas due to tuberous sclerosis complex

The efficacy, safety and durability of selective renal arterial embolization in treating symptomatic and asymptomatic renal angiomyolipoma

OBJECTIVE

To review the long-term outcome of selective renal arterial embolization (SAE) in treating renal angiomyolipomas (AMLs) in both elective and emergency settings.

MATERIALS AND METHODS

Between October 1988 and September 2008, 27 patients (28 renal units) were treated with SAE, either on an emergency basis for 15 (53.6%) bleeding AMLs or prophylactically for 13 (46.4%) asymptomatic high-risk (size >4.1 cm) AMLs. Six males and 21 females with a mean age of 46.3 years (range, 26-68) were followed for a mean period of 7.1 years (range, 1.3-20.2) for recurrence of symptoms, need for re-embolization, or need for renal surgery. SAE outcome was evaluated using the Kaplan-Meier method. Predictor(s) of outcome were identified with univariate analysis by log-rank test.

RESULTS

Mean size of AMLs was 10.9 cm (range, 4-30). Eight (29.6%) patients had bilateral and 19 (70.4%) had unilateral AMLs. Seventeen (60.7%) kidneys had solitary AMLs; 11 (39.2%) kidneys had multicentric AMLs. Of the 15 bleeding AMLs, 12 (80%) patients required a blood transfusion. Twenty-six (93%) AMLs were successfully embolized in the first SAE. During follow-up, four (14.8%) patients required re-embolization. Renal surgery was required in four (14.8%) patients. From the Kaplan-Meier analysis, the overall renal surgery sparing rate at 5 years was 85% (95% CI: 71-99%), whereas the single session SAE success rate at 5 years was 63% (95% CI: 42-84%). Of all the variables, only AML >10 cm was significantly associated with the subsequent need for renal surgery (P = .03). No renal malignancy was noted at final follow-up.

CONCLUSIONS

SAE is effective and durable in preventing large AMLs from bleeding, treating AMLs presenting with bleeding, and sparing the need for renal surgery.

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.

Transcatheter renal artery embolization: clinical applications and techniques

Renal artery embolization is a minimally invasive procedure that is increasingly being used for treatment of a wide range of conditions. The main indications for renal artery embolization include (1) prenephrectomy and preradiofrequency ablation infarction of renal tumors, (2) management of renal angiomyolipomas, (3) palliations of unresectable renal malignancy, (4) renal hemorrhage (life-threatening or chronic debilitating hematuria), (5) arteriovenous fistulas, (6) vascular malformations, (7) renal artery aneurysms and pseudoaneurysms, and other less common indications, such as severe hydronephrosis and hypertension. A variety of embolic materials are available, such as metal coils, sclerosants (glue, Onyx, absolute ethanol, lipiodol), and particulate embolic agents (polyvinyl alcohol particles and embospheres). Selection of the appropriate agent depends on the clinical application, technical and clinical endpoints, as well as the pathology lesion(s) targeted. Renal artery embolization can be performed alone or in combination with remodeling techniques, stent-grafting, and balloon- or stent-assisted coiling in more complicated cases. The procedure is generally regarded as safe and effective for diverse applications and is considered as an evolving area in the field of endoluminal therapy.

A case of lipiduria after arterial embolization for renal angiomyolipomas

We report the case of a 31-year-old woman who suffered lipiduria after selective transcatheter arterial embolization for renal angiomyolipoma (AML). Computed tomography confirmed cystic liquefactive necrosis with fat-fluid level in AML. Although the process by which AML fat tissue excretion occurs is not clear, we speculated that the infarcted AML was connected to the urinary collection duct system and subsequently its adipose component was excreted into the urine.

The management of renal angiomyolipomas in a patient with tuberous sclerosis

BACKGROUND

A 17-year-old girl, who was diagnosed with tuberous sclerosis in infancy, presented with multiple bilateral renal masses, the largest of which was 6.0 cm in diameter on the left side.

INVESTIGATIONS

History and physical examination, ultrasonography, MRI, CT, magnetic resonance angiography, and measurement of serial creatinine levels.

DIAGNOSIS

Bilateral angiomyolipomas.Management Observation, serial imaging, embolization and infarction.

Long-term follow-up of the treatment of renal angiomyolipomas after selective arterial embolization with alcohol

STUDY TYPE

Therapy (case series).

LEVEL OF EVIDENCE

4.

OBJECTIVE

To present our institution's experience of selective embolization of renal angiomyolipomas with alcohol and the long-term follow up data.

PATIENTS AND METHODS

This retrospective study included 34 patients treated between October 1997 and October 2007 (29 women and five men, mean age 44 years). Of these patients, nine had tuberous sclerosis, 14 were bilateral and 16 were multifocal. Indications for treatment were previous haemorrhage (14), size >4 cm (19) and increasing size over a short period (one). The largest treated lesion was 24.4 cm, and the mean (range) size was 11.9 (2.9-24.4) cm. All patients were treated by selective embolization using a mixture of alcohol and lipiodol. Three patients also had coiling of aneurysms and two patients had additional embolization with polyvinyl alcohol particles. The follow-up was both radiological and clinical, with recurrence defined as growth by >2 cm or symptoms requiring further treatment.

RESULTS

The technical success rate was 100%, with only one significant complication of non-target renal embolization, with self-limiting effects. Minor complications included 11 patients with post-embolization syndrome, all of which settled with conservative measures. The mean (range) combined radiological and clinical follow-up was 44.2 (12-116) months, with all patients having a follow-up of >1 year. Radiological success was achieved in 97%, with only one lesion growing by >2 cm. The combined clinical and radiological success rate was 85%, with two patients undergoing surgery, two having repeat embolization and one currently offered surgery due to a recent increase in size.

CONCLUSION

Our study provides long-term evidence that selective arterial embolization with alcohol is a safe and effective method for improving clinical symptoms (85%) and preventing tumour progression (97%) in patients with renal angiomyolipoma.

Embolization of renal angiomyolipomas: short-term and long-term outcomes, complications, and tumor shrinkage

This study retrospectively evaluated outcomes, complications, and tumor shrinkage in renal angiomyolipomas after transcatheter arterial embolization (TAE). All renal angiomyolipoma patients who underwent TAE between August 2000 and December 2008 and had short-term (<or=6 months) or long-term (>6 months) follow-up images were evaluated. Complications and tumor relapse after TAE were reviewed. The sizes of embolized tumors were measured to calculate size reductions and reduction rates after TAE. Differences in tumor size, size reduction, and reduction rate between different time points (pre-TAE, short-term follow-up, and long-term follow-up) and groups (completely and incompletely embolized) were determined. Eleven renal angiomyolipoma patients who had undergone TAE were included. Seven (63.6%) patients had postembolization syndrome and one had abscess formation following TAE. Two patients had a tumor relapse (18.2%). The mean tumor size was 8.57+/-2.66 cm on pre-TAE images. The mean size reduction was 3.1 cm (33.3%) and 3.8 cm (43.0%) at short-term and long-term follow-up. Tumor sizes differed significantly between pre-TAE and short-term (p=0.004) or long-term images (p=0.022) but not between short-term and long-term images (p=0.059). Results stratified by the completeness of embolization indicate that only the short-term size reduction rate differed significantly (p=0.025), while the long-term reduction rate and short- and long-term follow-up tumor size and size reduction were comparable between the two groups. In conclusion, selective TAE is effective for tumor shrinkage in most renal angiomyolipomas, with acceptable complication and relapse rates. Tumor shrinkage occurring within 6 months after TAE may reflect the long-term effect of TAE.

Evaluation of renal function of angiomyolipoma patients after selective transcatheter arterial embolization

BACKGROUND

Angiomyolipoma patients may have renal insufficiency before selective transcatheter arterial embolization (TAE) or may undergo subsequent surgery after TAE. Therefore, this retrospective study examined our experience with TAE or TAE and subsequent surgery on renal function of angiomyolipoma patients with and without preexisting renal insufficiency.

METHODS

25 patients who had undergone TAE for renal angiomyolipoma over a 7-year period were reviewed. The 25 patients were grouped according to whether or not they had undergone further surgery. Preexisting renal insufficiency was compared between the 2 groups. The TAE and surgery group was further subdivided into 2 subgroups according to total nephrectomy or not. The TAE-alone group was further subdivided into 2 subgroups by presence of preexisting renal insufficiency or not. In each group and subgroup, pre-TAE and post-TAE renal function, including serum creatinine and creatinine clearance were compared.

RESULTS

TAE rather than TAE and surgery was more likely chosen in the presence of preexisting renal insufficiency (6/13 versus 1/12, P=0.035). In TAE-alone patients, no statistical differences were noted between serum creatinine and creatinine clearance before and after TAE. Conversely, TAE and surgery patients who had undergone total nephrectomy rather than nephron-sparing surgery differed significantly in preand post-TAE serum creatinine (0.77 versus 1.07, P=0.014) and creatinine clearance (98.1 versus 70.7, P=0.032).

CONCLUSIONS

This study demonstrated that TAE alone for treating renal angiomyolipomas was able to preserve renal function, despite the presence of mild preexisting renal insufficiency. Conversely, surgery after TAE, particularly total nephrectomy, should be avoided whenever possible.

The pathogenesis and imaging of the tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal-dominant disorder characterized by the formation of hamartomatous lesions in multiple organ systems. It is the second most common neurocutaneous syndrome after neurofibromatosis type 1 and has been recognized since the late 1800s. Although the disease has complete penetrance, there is also high phenotypic variability: some patients have obvious signs at birth, while others remain undiagnosed for many years. In addition to skin lesions, TSC patients develop numerous brain lesions, angiomyolipoma (AMLs), lymphangiomyomatosis (LAM) in the lungs, cardiac rhabdomyomas, skeletal lesions, and vascular anomalies, all of which are well seen with medical imaging. Our knowledge of TSC genetics and pathophysiology has expanded dramatically in recent years: two genetic loci were discovered in the 1990s and recent elucidation of TSC's interaction with the mTOR pathway has changed how we manage the disease. Meanwhile, medical imaging is playing an increasingly important role in the diagnosis, management, and treatment of TSC. We provide an update on the genetics and pathophysiology of TSC, review its clinical manifestations, and explore the breadth of imaging features in each organ system, from prenatal detection of cardiac rhabdomyomas to monitoring rapamycin therapy to treatment of AMLs by interventional radiology.

Tuberous sclerosis

Tuberous sclerosis is a genetic multisystem disorder characterised by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver. The affected genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian-target-of-rapamycin pathway, which controls cell growth and proliferation. Variations in the distribution, number, size, and location of lesions cause the clinical syndrome to vary, even between relatives. Most features of tuberous sclerosis become evident only in childhood after 3 years of age, limiting their usefulness for early diagnosis. Identification of patients at risk for severe manifestations is crucial. Increasing understanding of the molecular abnormalities caused by tuberous sclerosis may enable improved management of this disease.

[Renal angiomyolipoma: presentation, treatment and results of 20 cases]

INTRODUCTION

Renal angiomyolipoma is a benign tumour, but its spontaneous rupture may become threatening for patient's live. Both surgery and selective arterial embolization are accepted treatments for this lesion.

OBJECTIVES

Analyze renal angyolipoma treated in our center, their clinical outcome and treatment purposed in each case.

MATERIAL AND METHODS

We retrospectively analyse 20 cases of patients with renal angiomyolipoma treated in our centre from March 1996 to March 2006. We describe tumour characteristics, treatment followed and results obtained.

RESULTS

Patients suffering from tuberous sclerosis (20%) showed multiple bilateral tumours, with size similar to the rest of patients. Diagnosis of tuberous sclerosis was the only factor attached to spontaneous rupture of those lesions. Four of 9 emergency embolized patients (44.4%) required from second treatment because of recurrent haemorrhage, and 4 of the 16 embolization episodes (25%) presented post-embolization syndrome, both with no predicting factors attached. Reduction of less than one third of the inicial diameter was observed in 58.4% of embolized tumours, which used to be multiple, bilateral and of size larger to the rest. No significative differences were observed in plasmatic creatinine after and before treatments.

CONCLUSIONS

Renal angiomyolipoma may behave in an aggressive way in patients with tuberous sclerosis. No predicting factors of recurrent haemorrhage or post-embolization syndrome were observed. Both surgery and arterial embolization have proved not to compromise renal function in treated patients.

Long-term functional and morphological effects of transcatheter arterial embolization of traumatic renal vascular injury

OBJECTIVE

To assess the long-term morphological and functional outcome of superselective transarterial embolization (TAE) for treating traumatic renal vascular injury.

PATIENTS AND METHODS

The surgical records of 124 patients with traumatic renal vascular injury managed by TAE between 1990 and 2004 were reviewed, of whom 81 completed a long- term follow-up and were included in the final analysis. Patients were followed using serum creatinine levels, grey-scale ultrasonography, intravenous urography (IVU) and radioisotopic renography using (99m)Tc-mercapto-acetyl triglycine (MAG3) and (99m)Tc-dimercaptosuccinic acid (DMSA).

RESULTS

Embolization resulted in the cessation of haematuria in all patients but two (97.5%). At 3 months, serum creatinine levels increased in four of nine patients with a solitary kidney, but only one of them required haemodialysis. After a mean follow-up of 4.6 years, IVU showed a normal calyceal configuration in 70% of renal units, pyelonephritic changes in 26% and no dye excretion in 4%. DMSA scans showed no evidence of photopenic areas in 17 renal units (21%). The mean (sd) percentage of DMSA uptake by the corresponding kidney improved from 24 (9)% at the 3-month scans to 32 (10)% at the last follow-up scan (P < 0.001). Using MAG3, the mean (sd) glomerular filtration rate improved significantly from 26 (11) mL/min at the 3-month scan to 32 (9) mL/min at the last follow-up (P < 0.05).

CONCLUSIONS

Superselective TAE is safe and effective for traumatic renal vascular injury. The short-term deleterious effects were more pronounced in patients with a solitary kidney. The long-term follow-up showed functional and morphological improvements in the embolized renal units.

Conservative management of giant symptomatic angiomyolipomas in patients with the tuberous sclerosis complex

OBJECTIVE

To present two patients with the tuberous sclerosis complex in whom giant angiomyolipomas (AMLs) were managed conservatively for >20 years, as large (>4 cm) symptomatic AMLs are generally treated with embolization or nephrectomy because of the risks of haemorrhage.

PATIENTS AND METHODS

The first patient initially presented with bilateral renal AMLs replacing >70% of his parenchymal volume, and a large left renal cyst. Since presentation he was hospitalized three times, but has had no transfusions or procedures to treat his AMLs. His renal function has remained stable during this 21-year interval. The second patient initially presented with bilateral renal AMLs that were not amenable to nephron-sparing surgery. After removing her nonfunctioning left kidney, the 24-cm AML in her right kidney was managed conservatively for >20 years, during which she had 44 transfusions and 11 hospitalizations before uncomplicated right nephrectomy and subsequent need for haemodialysis.

CONCLUSION

Conservative management of AMLs can preserve renal function for >20 years in patients with tuberous sclerosis at high risk of end-stage renal disease.

Urological counseling and followup in pediatric tuberous sclerosis complex

PURPOSE

We review our experience with renal manifestations in pediatric patients with the tuberous sclerosis complex, and offer recommendations for urological counseling, followup and treatment of these patients.

MATERIALS AND METHODS

We reviewed clinical notes on 41 patients with the tuberous sclerosis complex followed at our institution from childhood. Patient data were gathered in a database focusing on renal involvement. The latter was assessed by periodic clinical evaluations and ultrasound. The risk of renal involvement was evaluated in relation to patient age, genotypic pattern and number of extrarenal manifestations.

RESULTS

Overall, 15 patients (36.6%) had renal involvement. The latter increased with age and was more common in cases with TSC2 genotypic pattern or multiple extrarenal manifestations. Angiomyolipomas were the most common lesions (11 patients), followed by renal cysts (2) and polycystic kidney disease (2). Cystic lesions were the most common in patients younger than 16 years. Renal failure developed in the 2 patients with polycystic kidney disease by the 2nd decade of life. Overall, treatment was required in 2 cases of symptomatic angiomyolipoma. Both patients were female, and had multiple extrarenal manifestations and bilateral renal involvement. One patient underwent open surgery at age 21.3 years and 1 underwent radiological embolization at age 23.4 years.

CONCLUSIONS

Pediatric patients with the tuberous sclerosis complex should undergo urological evaluation and followup. Although most of the lesions remain silent during childhood, the incidence of renal involvement increases with age. The need for treatment is highest in females with multiple extrarenal manifestations and bilateral renal involvement.

Simple enucleation for the treatment of renal angiomyolipoma

OBJECTIVES

To report on the role of simple enucleation for treating renal angiomyolipoma (AML) in a series of patients treated in our department.

PATIENTS AND METHODS

We retrospectively reviewed the data of all 37 patients with a histopathological diagnosis of renal AML who had either radical nephrectomy (three) or nephron-sparing surgery by simple enucleation (34) between January 1986 and December 2005. Indications for intervention included either symptomatic AML or a tumour of >4 cm, regardless to the presence of symptoms or renal masses suspicious of malignancy. The patients' status was evaluated last in October 2006.

RESULTS

The mean (sd, median, range) pathological tumour size was 5.2 (3.4, 4.8, 1.5-15) cm; five patients (15%) were affected by tuberous sclerosis. Simple enucleation was successful in all patients but in three (9%) a sharp dissection a few millimetres from the tumour was used during critical steps of the procedure where it seemed difficult to define the right plane of enucleation. Warm ischaemia was used in 79% of patients, with a mean ischaemic time of 11.2 min. Two patients (6%) required renal hypothermia. A simple parenchymal compression was used in five cases (15%). The mean (range) intraoperative blood loss was 170 (70-650) mL. None of the patients had postoperative bleeding requiring re-intervention but one (3%) required two units of blood after surgery. There were no major complications, e.g. prolonged acute tubular necrosis/chronic renal insufficiency and urinary leakage/urinoma, but two patients had urosepsis not associated with perirenal fluid collection and that required targeted antibiotic therapy. At a mean (median, range) follow-up of 56 (50.5, 10-120) months none of the patients had local tumour recurrence. Two patients had a small AML elsewhere in the operated kidney, detected 18 and 36 months after surgery, with a kidney recurrence rate of 6%.

CONCLUSIONS

Our data confirm the optimum results of simple enucleation for renal AMLs; this technique provides excellent long-term local control and no patient had urinary leakage/fistula afterward.

Rectal angiolipoma: A case report and review of literature

Angiolipoma is a rare vascular variant of the benign lipomatous tumors and is generally seen in subcutaneous tissues. We report a 70-year-old female with abdominal distension not related to rectal small polypoid mass with peduncule described as angiolipoma by histologically, and review the literature.

CT angiography in renal angiomyolipomas

Renal angiomyolipomas are fat containing tumours, which are associated with a strong risk of hemorrhage due to the presence of abnormal vessels and pseudoaneurysms. We present three cases of ruptured renal angiomyolipomas with multiple or large pseudoaneurysms diagnosed by CT angiography which enabled emergent endovascular intervention; and propose CT angiography as the diagnostic modality of choice, particularly in emergency situations.