Embolization of renal angiomyolipomata in patients with tuberous sclerosis complex

Safety and efficacy of transcatheter arterial embolization in renal angiomyolipomas: a systematic review and meta-analysis

PURPOSE

Transcatheter arterial embolization (TAE) is increasingly utilized in the management of renal angiomyolipomas (AML). However, the growth in its application has not been matched by a proportional increase in the level of evidence validating its safety and efficacy. This meta-analysis aims to evaluate TAE in managing renal AMLs by examining the effects of tumour size reduction and technical success.

METHODS

A literature search of several databases was conducted from inception to July 2023. Eligible studies reported adult patients (≥ 18 years old) who underwent TAE for renal AML. The pooled proportions were analyzed using a random-effects model. This review was registered in PROSPERO (CRD42023441331).

RESULTS

A total of 32 studies comprising 1087 patients were included. The average preoperative tumour size across renal AMLs was 8.79 cm (95% CI: 7.64, 9.93; I2 = 97%) and the post-operative tumour size was 6.47 cm (95% CI: 5.44, 7.50; I2 = 98%). The mean decrease in tumour size was 1.85 cm (95% CI: 1.69, 2.00; I2 = 23%), whereas the mean reduction in tumour size percentage was 43.30% (95% CI: 34.30, 52.30; I2 = 98%). The technical success rate from 1059 embolizations was 95.70% (95% CI: 0.94, 0.97; I2 = 44%), with 65 procedural failures reported.

CONCLUSION

This meta-analysis provides insights into the efficacy of TAE for renal AMLs, emphasizing notable tumour size reduction and a high technical success rate for selected patients. Despite identified biases, the findings support TAE as a valuable intervention, warranting further research to refine safety profiles and optimize patient outcomes.

Neoadjuvant everolimus in renal angiomyolipoma with or without tuberous sclerosis complex: Results from a multicenter, retrospective study

OBJECTIVES

To assess the efficacy and safety of preoperative neoadjuvant everolimus in renal angiomyolipomas (AML) patients with or without Tuberous Sclerosis Complex (TSC).

MATERIALS AND METHODS

This multi-institutional retrospective study enrolled renal AML patients who underwent partial nephrectomy (PN) or total nephrectomy after receiving at least 1 month of pre-operative everolimus. Imaging evaluations were collected before and after treatment, along with demographic, surgical, and follow-up information. The primary outcome was tumor volume reduction of ≥25%, with additional outcomes including recurrence, perioperative outcomes, renal function, and safety.

RESULTS

From January 2015 to July 2022, 68 renal AML patients were studied-41 with TSC and 27 without. During everolimus treatment, 61.0% (25/41) of TSC patients and 44.4% (12/27) of non-TSC patients achieved tumor reduction of ≥25%. Additionally, 41.5% (17/41) of TSC patients and 18.5% (5/27) of non-TSC patients achieved a ≥ 50% reduction. Three TSC patients and 1 non-TSC patient discontinued treatment due to side-effects. Most patients (92.7% TSC, 85.2% non-TSC) underwent PN. After everolimus treatment, the necessary total nephrectomy decreased to 41.2% (7/17) from baseline. Postoperatively, 1 grade 3 and 3 grade 2 complications occurred, with no grade 4 or 5 complications. After a median follow-up of 24 months, only 1 TSC patient recurred with a diameter >3 cm. Retrospective nature is the major limitation of this study.

CONCLUSION

Everolimus was effective and well-tolerated in neoadjuvant treatment for renal AML, especially in TSC patients. This neoadjuvant combination strategy of everolimus and PN could effectively controls recurrence and preserves renal function.

Lymphangioleiomyomatosis in patients with tuberous sclerosis: a national centre audit

BACKGROUND

Lymphangioleiomyomatosis (LAM) is common in tuberous sclerosis complex (TSC) yet under recognised with management mostly based upon evidence obtained from patients with sporadic LAM. We performed a prospective audit of patients with TSC-LAM attending a national referral centre to inform management guidelines.

METHODS

The UK LAM Centre was established in 2011 and conducts a prospective audit of pre-defined quality outcomes for all subjects. Audit data are reported on all patients with TSC-LAM and a comparator population of patients with sporadic LAM.

RESULTS

Between 2011 and 2022, 73 patients were seen with TSC-LAM. All were women with a mean (SD) age of 39 (12) years. Referral rates were similar over the study period including after the introduction of CT screening. Median age of diagnosis with TSC was 11 years (range 0-70) with one third diagnosed with TSC as adults. Compared with all TSC patients in the 'TOSCA' registry, TSC-LAM patients tended to have been diagnosed with TSC at an older age, had fewer neuro-cognitive manifestations and were more likely to have angiomyolipoma. The most common presentations of TSC-LAM were following workup for angiomyolipoma, pneumothorax or dyspnoea with only one fifth detected after CT screening. Baseline FEV1 and DLCO at first assessment were reduced to 77 and 63% predicted respectively and were similar to patients with sporadic LAM. During follow-up, FEV1 fell by a mean of 81 ml/year and DLCO fell by 0.309 mmol/ml/kPa/year in patients not being treated with an mTOR inhibitor. 55% required treatment with either sirolimus or Everolimus for LAM or angiomyolipoma respectively. For those treated with an mTOR inhibitor, mean FEV1 fell by 3 ml/year and DLCO increased by 0.032 mmol/ml/kPa/year and was similar to sporadic LAM. Risk of death due to LAM or need for lung transplant in patients with TSC-LAM was 0.67%/year.

CONCLUSIONS

Despite screening recommendations, LAM is often diagnosed in TSC after symptoms develop which may delay treatment. Complications including pneumothorax and loss of lung function are significant and similar to sporadic LAM. Work is needed to implement the recommended CT screening for LAM and improve respiratory care for TSC-LAM.

French recommendations for the diagnosis and management of lymphangioleiomyomatosis

BACKGROUND

The present article is an English-language version of the French National Diagnostic and Care Protocol, a pragmatic tool to optimize and harmonize the diagnosis, care pathway, management and follow-up of lymphangioleiomyomatosis in France.

METHODS

Practical recommendations were developed in accordance with the method for developing a National Diagnosis and Care Protocol for rare diseases of the Haute Autorité de Santé and following international guidelines and literature on lymphangioleiomyomatosis. It was developed by a multidisciplinary group, with the help of patient representatives and of RespiFIL, the rare disease network on respiratory diseases.

RESULTS

Lymphangioleiomyomatosis is a rare lung disease characterised by a proliferation of smooth muscle cells that leads to the formation of multiple lung cysts. It occurs sporadically or as part of a genetic disease called tuberous sclerosis complex (TSC). The document addresses multiple aspects of the disease, to guide the clinicians regarding when to suspect a diagnosis of lymphangioleiomyomatosis, what to do in case of recurrent pneumothorax or angiomyolipomas, what investigations are needed to make the diagnosis of lymphangioleiomyomatosis, what the diagnostic criteria are for lymphangioleiomyomatosis, what the principles of management are, and how follow-up can be organised. Recommendations are made regarding the use of pharmaceutical specialties and treatment other than medications.

CONCLUSION

These recommendations are intended to guide the diagnosis and practical management of pulmonary lymphangioleiomyomatosis.

Prophylactic Steroids for Preventing Postembolization Syndrome after Transcatheter Arterial Embolization of Renal Angiomyolipoma: A Comparative Study

Purpose

Postembolization syndrome (PES) after renal arterial embolization (RAE) can reduce the patient's tolerance of the procedure and extend the length of hospital stay. We aimed to assess the efficacy of steroid administration in preventing PES in patients undergoing RAE for angiomyolipoma (AML).

Material and Methods

Between May 2004 and March 2020, 29 RAE procedures in 26 patients with AML were performed. Patient information, including age, sex, tumor size, tuberous sclerosis complex-associated/sporadic AML, hemorrhagic/nonhemorrhagic AML, embolic material, steroid use, medication type, some blood laboratory parameters, hospital stay, and PES occurrence were retrospectively obtained. The prophylactic steroid protocol used in the study was as follows: 250 mg of intravenous methylprednisolone (Solu-Medrol) 2 h before the RAE procedure, followed by 2 days of intravenous prednisolone (Predonine; 2 mg/kg/day), which was tapered by halving the dose every 2 days within the course of 2 weeks. After the discharge, intravenous prednisolone was changed to oral prednisolone (Predonine). PES was defined as the presence of fever, pain, nausea, or vomiting. Data were compared between the steroid and non-steroid groups and between PES and non-PES groups.

Results

The PES incidence rate was 76%, and a comparison between the steroid and non-steroid groups revealed that steroid use significantly decreased the incidence of PES (P < 0.001), including fever (P < 0.001), pain (P = 0.005), and nausea (P = 0.028). The use of anti-inflammatory drugs during the hospital stay was significantly lower in the steroid group (P = 0.019). Moreover, in the steroid group, C-reactive protein level was significantly lower (P = 0.006), whereas white blood cell count was significantly higher (P = 0.004). Conversely, the median length of hospital stay was not significantly shorter in the steroid group (P = 0.292).

Conclusions

The prophylactic use of steroids before and after embolization of renal AML may be effective in preventing PES in this small retrospective study.

Progress in Tuberous Sclerosis Complex Renal Disease

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects both fetal development and postnatal tissue growth, resulting in altered brain structures and a tumor predisposition syndrome. Although every organ system is affected by the disease, kidney involvement is a leading cause of death in adults with TSC. Over the past decade, significant progress has been made in understanding the renal disease. This review focuses on the cystic and solid renal lesions in TSC, including their pathobiology and treatment.

Use of Microballoon Catheter in Transarterial Ethanol Embolization of Renal Angiomyolipoma: A Retrospective Comparative Study with Historical Control?

Purpose:

To clarify the utility of microballoon catheter in renal arterial ethanol embolization of renal angiomyolipoma (AML).

Material and Methods:

A total of 20 patients (15 women, 5 men) with median age of 45 years (39-60 years) underwent embolization to treat 22 AMLs. A mixture of ethanol and iodized oil was injected into the feeding arteries of 13 tumors using balloon occlusion (the balloon embolization group) with a microballoon catheter and 9 tumors without using balloon occlusion (the non-balloon embolization group). Changes in the maximum tumor diameter, tumor volume, and adverse events were evaluated.

Result:

The median baseline maximum tumor diameters and volumes were 6.3 cm and 61.4 cm³ in the balloon embolization group, and 4.6 cm and 40.1 cm³ in the non-balloon embolization group, respectively. Tumor enhancement disappeared on postembolization angiography in all cases. All tumors shrunk after embolization. There were no statistically significant differences in the percent decrease in the maximum tumor diameter and volume at 10-12 month between balloon occlusion group (31.5% and 67.9%) and control group (34.8% and 62.6%). Fever was significantly more frequent when balloon occlusion was used: 38% vs. 0% (p = 0.03). No major complication was observed in either patient group.

Conclusions:

Balloon occlusion may not affect tumor shrinkage when embolizing AMLs with a mixture of ethanol and lipiodol.

Selective Arterial Embolization of Renal Angiomyolipomas with a N-Butyl Cyanoacrylate-Lipiodol Mixture: Efficacy, Safety, Short- and Mid-Term Outcomes

Selective arterial embolization (SAE) for renal angiomyolipoma (rAML) is effective to treat or prevent bleeding. We report our experience using a cyanoacrylate–Lipiodol mixture. We performed a single-center retrospective review of all rAMLs embolized with cyanoacrylate glue between July 2014 and June 2020. Demographics, tuberous sclerosis complex (TSC) status, clinical presentation, angiography features, and follow-up data were recorded. Pre- and post-procedure rAML sizes and volumes were estimated from computed tomography (CT) or magnetic resonance imaging (MRI) studies. Kidney function was assessed before and after the procedure. We identified 24 patients (22 females and 2 males, mean age 51 years) treated for 27 AMLs, either prophylactically (n = 20) or as an emergency (n = 4). Technical success was achieved for 25/27 AMLs; two patients, each with a single AML, required nephrectomy and repeated embolization, respectively. Major complications occurred in three patients and minor complications such as postembolization syndrome in 15 patients. AML volume reduction after embolization was 55.1% after a mean follow-up of 15 months (range, 1–72 months). Factors associated with greater volume reduction were a smaller percentage of fat (p = 0.001), larger initial rAML volume (p = 0.014), and longer follow-up (p = 0.0001). The mean creatinine level did not change after SAE. Embolization of rAMLs with a mixture of cyanoacrylate and Lipiodol is feasible, safe, and effective in significantly decreasing tumor volume.

Kidney intercalated cells and the transcription factor FOXi1 drive cystogenesis in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is caused by mutations in TSC1 or TSC2 gene and affects multiple organs, including the kidney, where it presents with angiomyolipomata and cysts that can result in kidney failure. The factors promoting cyst formation and tumor growth in TSC are incompletely understood. Current studies demonstrate that kidney cyst epithelia in TSC mouse models and in humans with TSC are composed of hyperproliferating intercalated cells, along with activation of H⁺-ATPase and carbonic anhydrase 2. Interfering with intercalated cell proliferation completely inhibited and inactivating carbonic anhydrase 2 significantly protected against cyst formation in TSC. Targeting the acid base and/or electrolyte transporters of intercalated cells may provide a therapeutic approach for the treatment of kidney cysts in TSC.

Tuberous sclerosis complex (TSC) is caused by mutations in either TSC1 or TSC2 genes and affects multiple organs, including kidney, lung, and brain. In the kidney, TSC presents with the enlargement of benign tumors (angiomyolipomata) and cysts, which eventually leads to kidney failure. The factors promoting cyst formation and tumor growth in TSC are incompletely understood. Here, we report that mice with principal cell-specific inactivation of Tsc1 develop numerous cortical cysts, which are overwhelmingly composed of hyperproliferating A-intercalated (A-IC) cells. RNA sequencing and confirmatory expression studies demonstrated robust expression of Forkhead Transcription Factor 1 (Foxi1) and its downstream targets, apical H⁺-ATPase and cytoplasmic carbonic anhydrase 2 (CAII), in cyst epithelia in Tsc1 knockout (KO) mice but not in Pkd1 mutant mice. In addition, the electrogenic 2Cl⁻/H⁺ exchanger (CLC-5) is significantly up-regulated and shows remarkable colocalization with H⁺-ATPase on the apical membrane of cyst epithelia in Tsc1 KO mice. Deletion of Foxi1, which is vital to intercalated cells viability and H⁺-ATPase expression, completely abrogated the cyst burden in Tsc1 KO mice, as indicated by MRI images and histological analysis in kidneys of Foxi1/Tsc1 double-knockout (dKO) mice. Deletion of CAII, which is critical to H⁺-ATPase activation, caused significant reduction in cyst burden and increased life expectancy in CAII/Tsc1 dKO mice vs. Tsc1 KO mice. We propose that intercalated cells and their acid/base/electrolyte transport machinery (H⁺-ATPase/CAII/CLC-5) are critical to cystogenesis, and their inhibition or inactivation is associated with significant protection against cyst generation and/or enlargement in TSC.

[Tuberous sclerosis system: A review]

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects different organs and caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. TSC1 or TSC2 gene mutation lead to dysfunction of hamartin or tuberin, respectively. Hamartin and tuberin form a protein complex that helps regulate cellular proliferation. These proteins form a complex that constitutively inhibits the mammalian target of rapamycin (mTOR) signaling pathway, leading to permanent activation of mTOR signaling within all TSC-associated lesions. Major features of TSC include tumors of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. These disorders are usually diagnosed in children and adults. Specific guidelines for diagnosis, surveillance, and management have been proposed by the International Tuberous Sclerosis Complex Consensus Group. Several randomized controlled trials led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas, refractory epilepsy and pulmonary lymphangioleiomyomatosis.

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.

Angiomyolipoma of the kidney: from simple hamartoma to complex tumour

Angiomyolipoma is the most common mesenchymal tumour of the kidney, even if for a long time it has been viewed as a hamartoma rather than a neoplasm. It belongs to a family of neoplasms, named PEComa, characterised by the constant presence of perivascular epithelioid cells that co-express smooth muscle and melanogenesis markers. Angiomyolipoma can occur in patients with tuberous sclerosis, a hereditary syndrome due to the alteration of TSC1 or TSC2 genes, or sporadically. Angiomyolipoma and its variants are indolent tumours; however, some epithelioid angiomyolipomas/pure epithelioid PEComas are aggressive, and criteria for malignancy have been proposed to identify those cases. Although typical angiomyolipoma is a straightforward diagnosis, pathologists should be aware of the wide morphological spectrum of its variants which could be tricky in routine clinical practice and could require immunohistochemical analysis for resolution. The differential diagnosis may range from an inflammatory process (for instance xanthogranulomatous pyelonephritis) to the most common renal cancers and sarcomas. The immunoexpression of melanogenesis markers (HMB45 and Melan-A) and cathepsin K is extremely helpful in the majority of cases. Recently, a subset of epithelioid angiomyolipoma/pure epithelioid PEComa harbouring TFE3 gene fusions has been described, raising questions about its relationship with the family of perivascular epithelioid cell tumour. The activation of the mTOR pathway due to genetic alterations of tuberous sclerosis complex in TSC1 or TSC2 genes in angiomyolipoma has also been reported as well as the subsequent therapeutic implications.

Selective Arterial Embolization for Large or Symptomatic Renal Angiomyolipoma: 10 Years of Follow-up

OBJECTIVE

To assess long-term outcome after selective arterial embolization (SAE) as first-line treatment for large or symptomatic AML.

DESIGN, SETTING, AND PARTICIPANTS

Data from a prospectively maintained database on 71 patients who underwent SAE for large or symptomatic AML were reviewed. Patients with sporadic and tuberous-sclerosis-complex (TSC) were included.

OUTCOME MEASUREMENTS

The main endpoints were re-embolization rates, occurrence of clinical events related to AML, size of AML, and renal function.

RESULTS

Thirteen (19.1%) patients reported at least 1 major clinical event. Major complications affected 2 patients (2.9%), both ending in complete loss of renal unit function. Four renal units (5.9%) were eventually treated surgically. The re-embolization rate was 41.1%, with an average time from the initial to a repeat SAE of 2.18 years (range 0.31-10.65 years). The size of the tumor prior to SAE and after 5 and 10 years of follow-up were 8.9 cm (7-12), 6.5 cm (4-7.5), 7 cm (4-7.8), respectively [median (IQR)]. These results are translated to a size reduction of 27% in 10 years follow-up. Patients with TSC had larger tumors on long-term follow-up (77.8 vs 41.3 mm, P = .045). The long-term follow-up estimated average glomerular filtration rate was 81.97 (range 26-196). No patient needed renal replacement therapy, and disease-specific survival was 100%.

CONCLUSIONS

SAE is a safe treatment option for patients with symptomatic or large AML. It represents a minimally invasive intervention with good long-term outcome. SAE may be offered as first-line treatment in most cases, though, it is associated with high retreatment rates.

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.

Observational study of characteristics and clinical outcomes of Dutch patients with tuberous sclerosis complex and renal angiomyolipoma treated with everolimus

OBJECTIVE

To compare kidney size (used as proxy for total renal angiomyolipoma [rAML] size) and kidney function outcomes between patients with tuberous sclerosis complex (TSC) and rAML treated and not treated with everolimus.

METHODS

Medical charts of adults with TSC-associated rAML followed at a specialty medical center in the Netherlands (1990-2015). Included patients treated with everolimus (n = 33, of which 27 were included in the kidney size analyses and 27 in the kidney function analyses [21 patients in both]; index date = everolimus initiation) and non-treated patients (n = 39, of which 29 were included in the kidney size analyses and 33 in the kidney function analyses [23 patients in both]; index date = one date among all dates with outcome measurement).Percent change in kidney size and kidney function from the index date to the best measurement in the two years post-index date (best response) compared between patients treated and not treated with everolimus.

RESULTS

Compared with non-treated patients, significantly more everolimus-treated patients experienced a reduction in the size of their largest kidney in the two years post-index date (85.2% vs. 37.9%, p < 0.01). Also, there was a tendency towards more improvement in the estimated glomerular filtration rate (eGFR) among the everolimus-treated patients (55.6% vs. 33.3%, p = 0.08).

CONCLUSIONS

The study results suggest that everolimus is effective in controlling and even reversing the growth of the kidneys, used as a proxy for rAML size, as well as preserving or improving kidney function in patients with TSC and rAML treated in a real-world, observational setting.

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.

Treatment effect of mTOR-inhibition on tissue composition of renal angiomyolipomas in tuberous sclerosis complex (TSC)

Purpose

Tuberous sclerosis complex (TSC)-associated renal angiomyolipoma (AML) have a high lifetime risk of acute bleeding. MTOR-inhibitors are a promising novel treatment for TSC-AML, however adequate response to therapy can be difficult to assess. Early changes in MRI signal may serve as a novel early indicator for a satisfactory response to mTOR-inhibitor therapy of AML.

Materials and methods

Thirty-eight patients with the definite diagnosis of tuberous sclerosis receiving everolimus therapy and n = 19 patients without specific therapy were included. 1.5 Tesla MRI was performed including sequences with a selective fat suppression. Patients were investigated prior to the initiation of therapy (baseline) and after <3 months (n = 21 patients), 3 to 6 months (n = 32) and 18 to 24 months (n = 28). Signal and size changes of renal AMLs were assessed at all different timepoints. Signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) and size of angiomyolipomas were evaluated.

Results

Signal changes in 273 AMLs were evaluated. A significant and strong decrease of the CNR of AMLs following the initiation of therapy was measured in the fat-suppressed MR sequence at all time points, compared to the baseline: From 7.41±6.98 to 3.84±6.25 (p ≤ 0.05p = 0.002), 3.36±6.93 (p<0.0001), and 2.50±6.68 (p<0.0001) after less than 3 months, 3–6 months or 18–24 months of everolimus treatment, respectively. Also, a significant, however less pronounced, reduction of angiomyolipoma size in the different groups was measured (from baseline 2022.2±2657.7 mm2 to 1854.4±1670.9 mm2 (p = 0.009), 1875.5±3190.1 mm2 (p<0.001), and 1365.8 ± 1628.8 mm2 (p<0.0001) after less than 3 months, 3–6 months or 18–24 months of everolimus treatment, respectively). No significant changes in CNR (p>0.05) and size (p>0.05) were measured in the control group.

Conclusion

mTOR inhibitor therapy in TSC patients results in an early and pronounced fatty transformation of AMLs on MRI. Fatty transformation could represent a novel early indicator of response to therapy in this patient collective.

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.

Selective arterial embolization of symptomatic and asymptomatic renal angiomyolipomas: a retrospective study of safety, outcomes and tumor size reduction

BACKGROUND

Angiomyolipoma (AML) is the most common renal benign tumor. Treatment should be considered for symptomatic patients or for those at risk for complications, especially retroperitoneal bleeding which is correlated to tumor size, grade of the angiogenic component and to the presence of tuberous sclerosis complex (TSC). This study reports our single-center experience with the use of selective arterial embolization (SAE) in the management of symptomatic and asymptomatic renal AMLs.

METHODS

In this retrospective mono-centric study, all demographic and imaging data, medical records, angiographic features, outpatient charts and follow-up visits of patients who underwent prophylactic or emergency SAE for AMLs between January 2005 and July 2016 were reviewed. Tumor size and treatment outcomes were assessed at baseline and after the procedure during follow-up. Computed tomography (CT), magnetic resonance imaging (MRI) or ultrasonography was used to evaluate AML shrinkage. Renal function was measured pre- and post-procedure.

RESULTS

Twenty-three patients (18 females, 5 males; median age, 45 years; range, 19-85 years) who underwent SAE either to treat bleeding AML (n=6) or as a prophylactic treatment (n=17) were included. Overall, 34 AMLs were embolized. TSC status was confirmed for 6 patients. Immediate technical success rate was 96% and 4 patients benefitted from an additional procedure. Major complications occurred in 3 patients and minor post-embolization syndrome (PES) in 14 patients. The mean AML size reduction rate was 26.2% after a mean follow-up was 20.5 months (range, 0.5-56 months), and only non-TSC status was significantly associated with better shrinkage of tumor (P=0.022). Intralesional aneurysms were significantly more frequent in patients with hemorrhagic presentation (P=0.008). There was no change in mean creatinine level after SAE.

CONCLUSIONS

SAE is a safe and effective technique to manage renal AMLs as a preventive treatment as well as in emergency setting, with significant reduction in tumor size during follow-up. A multidisciplinary approach remains fundamental, especially for TSC patients. In addition to size, the presence of intralesional aneurysms should be considered in any prophylactic treatment decision.

Renal angiomyolipoma bleeding in a patient with TSC2/PKD1 contiguous gene syndrome after 17 years of renal replacement therapy

We report the case of a 32-year-old male diagnosed with TSC2/PKD1 contiguous gene syndrome, presenting with tuberous sclerosis (TS) and autosomal dominant polycystic kidney disease simultaneously. He progressed to end-stage renal disease and received a kidney transplant at the age of 12. The native kidneys presented angiomyolipomas (AML), which are common benign tumours in patients with TS. Seventeen years after transplantation, he presented with abdominal pain, anaemia and a retroperitoneal haematoma, the latter caused by renal AML bleeding. Selective embolisation was performed. Our patient could have benefited from the administration of mTOR inhibitors at transplant. This therapy is immunosuppressive and reduces the size of benign tumours in TS as well as the risk of rupture and bleeding. This patient did not receive mTOR inhibitors at the time of the transplant because the relationship between mTOR inhibitors and TS was unknown at that time. This case confirms the persistent risk of renal AML bleeding for both transplanted patients and patients on dialysis. As a result, we would recommend routine check-ups of native kidneys and nephrectomy assessment.

Optimal treatment of tuberous sclerosis complex associated renal angiomyolipomata: a systematic review

Renal angiomyolipomata associated with tuberous sclerosis complex are often bilateral, multiple and progressive. They cause significant morbidity and mortality in older children and adults. Surveillance and pre-emptive treatment reduce this risk. Recent research suggests treatment with mammalian target of rapamycin inhibitors is better at preventing bleeding, recurrence, and preserving renal function than percutaneous embolization.

Evolving Strategies in the Treatment of Tuberous Sclerosis Complex-associated Angiomyolipomas (TSC-AML)

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder characterized by the development of numerous benign tumors that occur in multiple organ systems throughout the lifetime of the affected individuals. Renal angiomyolipomas occur in up to 80% of TSC patients, and chronic kidney disease from increasing tumor burden is the primary cause of TSC-related mortality. Our review evaluates evidence for localized and systemic therapy in the management of TSC-angiomyolipomas. Urologists or nephrologists experienced in TSC disease should coordinate the care of TSC patients with renal involvement to improve care and reduce costs.

Differentiation of Sporadic Versus Tuberous Sclerosis Complex-Associated Angiomyolipoma

OBJECTIVE

We review the imaging of renal angiomyolipomas, including differentiation of tuberous sclerosis complex (TSC)-associated and sporadic renal angiomyolipomas and other solid renal tumors. We also focus on radiologic interventions and molecular targeting of the TSC genetic pathway.

CONCLUSION

Imaging plays a central role in the diagnosis and management of renal angiomyolipomas. It provides essential information to make the best therapeutic decisions about the interventional and pharmacologic options to help prevent bleeding and preserve functional parenchyma.

Evaluation of split renal function before and after renal arterial embolization for angiomyolipoma using absolute ethanol

PURPOSE

Transcatheter arterial embolization (TAE) with absolute ethanol is widely accepted as a therapeutic procedure for renal angiomyolipoma (AML). We aim to evaluate the split renal function before and after AE for renal AML by using 99m-technetium (99mTc)-mercaptoacetyltriglycine 3 (MAG3) renography.

METHODS

This study was approved by the Institutional Review Board. The study population comprised 11 renal AML patients (three males, eight females, age 55.1 ± 13.8 years, AML in eight right and three left kidneys) who received unilateral renal TAE with absolute ethanol from April 2002 to January 2013. Blood renal function (i.e. serum creatinine and estimated glomerular filtration rate [eGFR] and split effective renal plasma flow [ERPF]) calculated on 99mTc-MAG3 renography was compared before and within 1 week after renal AE. Statistical analysis was calculated using Wilcoxon signed-ranked test.

RESULTS

TAE for renal AML was technically successful in all patients. Serum creatinine and eGFR did not change before and after TAE. ERPF on the embolized kidney did not change before (127.3 ± 60.8 ml/min) and after (127.6 ± 47.4 ml/min) TAE (p = 0.9726). ERPF on the nonembolized kidney showed a statistically significant increase before (152.5 ± 46.8 ml/min) and within 1 week after (169.1 ± 41.5 ml/min) TAE (p = 0.0093 and p < 0.05, respectively).

CONCLUSION

TAE for renal AML may not induce renal dysfunction on the embolized kidney and may immediately increase the renal blood flow of the nonembolized kidney.

Renal artery embolization-indications, technical approaches and outcomes

Owing to improvements in catheters and embolic agents, renal artery embolization (RAE) is increasingly used to treat nephrological and urological disease. RAE has become a useful adjunct to medical resuscitation in severe penetrating, iatrogenic or blunt renal traumatisms with active bleeding, and might avoid surgical intervention, particularly among patients that are haemodynamically stable. The role of RAE in pre-operative or palliative management of advanced malignant renal tumours remains debated; however, RAE is recommended as a first-line therapy for bleeding angiomyolipomas and can be used as a preventative treatment for angiomyolipomas at risk of bleeding. RAE represents an alternative to nephrectomy in various medical conditions, including severe uncontrolled hypertension among patients with end-stage renal disease, renal graft intolerance syndrome or autosomal dominant polycystic kidney disease. RAE is increasingly used to treat renal artery aneurysms or symptomatic renal arteriovenous malformations, with a low complication rate as compared with surgical alternatives. This Review highlights the potential use of RAE as an adjunct in the management of renal disease. We first compare and contrast the technical approaches of RAE associated with the various available embolization agents and then discuss the complications associated with RAE and alternative procedures.

Management of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM), a multisystem disease affecting almost exclusively women, is characterized by cystic lung destruction and presents with dyspnea, recurrent pneumothoraxes, chylous effusions, lymphangioleiomyomas, and angiomyolipomas. It is caused by the proliferation of a cancer-like LAM cell that possesses a mutation in either the tuberous sclerosis complex (TSC)1 or TSC2 genes. This article reviews current therapies and new potential treatments that are currently undergoing investigation. The major development in the treatment of LAM is the discovery of two mammalian target of rapamycin (mTOR) inhibitors, sirolimus and everolimus, as effective drugs. However, inhibition of mTOR increases autophagy, which may lead to enhanced LAM cell survival. Use of autophagy inhibitors, for example, hydroxychloroquine, in combination with sirolimus is now the subject of an ongoing drug trial (SAIL trial). Another consequence of mTOR inhibition by sirolimus is an increase in Rho activity, resulting in reduced programmed cell death. From these data, the concept evolved that a combination of sirolimus with disruption of Rho activity with statins (e.g. simvastatin) may increase TSC-null cell death and reduce LAM cell survival. A combined trial of sirolimus with simvastatin is under investigation (SOS trial). Since LAM occurs primarily in women and TSC-null cell survival and tumor growth is promoted by estrogens, the inhibition of aromatase to block estrogen synthesis is currently undergoing study (TRAIL trial). Other targets, for example, estrogen receptors, mitogen-activated protein kinase inhibitors, vascular endothelial growth factor-D signaling pathway, and Src kinase, are also being studied in experimental model systems. As in the case of cancer, combination therapy may become the treatment of choice for LAM.

Role of embolization in the treatment of renal masses

Renal arterial embolization (RAE) performed for the treatment of renal masses has been proven to be a safe and effective technique, with several decades of experience. RAE is well tolerated with few complications, particularly if the time interval from embolization to surgery is reduced to less than 48 hours. Review of the literature suggests that RAE is also extremely effective for palliation of symptoms in the setting of nonoperative advanced stage renal cell carcinoma. In addition, this technique plays a large role in the management of angiomyolipomas that are symptomatic or at risk of spontaneous rupture. To date, RAE has not been evaluated in a randomized controlled setting, which has contributed to its underutilization. All of these potential benefits warrant the need for prospective studies for further validation.

Long-term results of preventive embolization of renal angiomyolipomas: evaluation of predictive factors of volume decrease

OBJECTIVES

To evaluate the efficacy of selective arterial embolization (SAE) of angiomyolipomas based on the percentage volume reduction after embolization and to identify predictive factors of volume decrease.

METHODS

Patients receiving prophylactic SAE of renal angiomyolipomas were included retrospectively over 3 years. The volume change after SAE and haemorrhagic or surgical events were recorded. Initial tumour volume, percentage tumour fat content, mean tumour density, embolic agent used, number of angiomyolipomas and tuberous sclerosis disease were evaluated as predictive factors of volume decrease.

RESULTS

A total of 19 patients with 39 angiomyolipomas were included with median follow-up of 28 months (interquartile range 21-37 months). All treatments were technically successful (92% primary and 8% secondary). No distal bleeding or any increase in size or surgical nephrectomy after SAE was recorded. Mean volume reduction was 72% (±24%). Volumes before SAE (R(2) = 0.276; p = 0.001), percentage fat content (R(2) = 0.612; p < 0.0001) and mean angiomyolipoma density (R(2) = 0.536; p < 0.0001) were identified as predictive factors of volume decrease. In multivariate regression, only percentage fat content influenced volume decreases.

CONCLUSIONS

SAE is an efficient treatment for angiomyolipoma devascularisation and volume reduction. A significant reduction of volume is modulated by the initial volume and tissue composition of the tumour.

KEY POINTS

• Selective arterial embolization is effective for angiomyolipoma devascularisation and volume reduction • Volume reduction depends of initial volume and tissue composition of the tumour • Selective arterial embolization is a low radiation treatment.

Tuberous sclerosis complex, mTOR, and the kidney: report of an NIDDK-sponsored workshop

Remarkable basic and translational advances have elucidated the role of the mammalian target of rapamycin (mTOR) signaling network in the pathogenesis of renal disease. Many of these advances originated from studies of the genetic disease tuberous sclerosis complex (TSC), leading to one of the clearest therapeutic opportunities to target mTOR with rapamycin and its analogs ("rapalogs"), which effectively inhibit mTOR complex 1 (mTORC1) by an allosteric mechanism. Clinical trials based on these discoveries have provided strongly positive therapeutic results in TSC (Bissler JJ, McCormack FX, Young LR, Elwing JM, Chuck G, Leonard JM, Schmithorst VJ, Laor T, Brody AS, Bean J, Salisbury S, Franz DN. N Engl J Med 358: 140-151, 2008; Krueger DA, Care MM, Holland K, Agricola K, Tudor C, Mangeshkar P, Wilson KA, Byars A, Sahmoud T, Franz DN. N Engl J Med 363: 1801-1811, 2010; McCormack FX, Inoue Y, Moss J, Singer LG, Strange C, Nakata K, Barker AF, Chapman JT, Brantly ML, Stocks JM, Brown KK, Lynch JP 3rd, Goldberg HJ, Young LR, Kinder BW, Downey GP, Sullivan EJ, Colby TV, McKay RT, Cohen MM, Korbee L, Taveira-DaSilva AM, Lee HS, Krischer JP, Trapnell BC. N Engl J Med 364: 1595-1606, 2011). In June 2013, the National Institute of Diabetes and Digestive and Kidney Diseases convened a small panel of physicians and scientists working in the field to identify key unknowns and define possible "next steps" in advancing understanding of TSC- and mTOR-dependent renal phenotypes. TSC-associated renal disease, which affects >85% of TSC patients, and was a major topic of discussion, focused on angiomyolipomas and epithelial cysts. The third major topic was the role of mTOR and mTOR inhibition in the pathogenesis and therapy of chronic renal disease. Renal cell carcinoma, while recognized as a manifestation of TSC that occurs in a small fraction of patients, was not the primary focus of this workshop and thus was omitted from panel discussions and from this report.

Everolimus for angiomyolipoma associated with tuberous sclerosis complex or sporadic lymphangioleiomyomatosis (EXIST-2): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Angiomyolipomas are slow-growing tumours associated with constitutive activation of mammalian target of rapamycin (mTOR), and are common in patients with tuberous sclerosis complex and sporadic lymphangioleiomyomatosis. The insidious growth of these tumours predisposes patients to serious complications including retroperitoneal haemorrhage and impaired renal function. Everolimus, a rapamycin derivative, inhibits the mTOR pathway by acting on the mTOR complex 1. We compared the angiomyolipoma response rate on everolimus with placebo in patients with tuberous sclerosis or sporadic lymphanioleiomyomatosis-associated angiomyolipomata.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, patients aged 18 years or older with at least one angiomyolipoma 3 cm or larger in its longest diameter (defined by radiological assessment) and a definite diagnosis of tuberous sclerosis or sporadic lymphangioleiomyomatosis were randomly assigned, in a 2:1 fashion with the use of an interactive web response system, to receive oral everolimus 10 mg per day or placebo. The primary efficacy endpoint was the proportion of patients with confirmed angiomyolipoma response of at least a 50% reduction in total volume of target angiomyolipomas relative to baseline. This study is registered with ClinicalTrials.gov number NCT00790400.

RESULTS

118 patients (median age 31·0 years; IQR 18·0–61·0) from 24 centres in 11 countries were randomly assigned to receive everolimus (n=79) or placebo (n=39). At the data cutoff, double-blind treatment was ongoing for 98 patients; two main reasons for discontination were disease progression (nine placebo patients) followed by adverse events (two everolimus patients; four placebo patients). The angiomyolipoma response rate was 42% (33 of 79 [95% CI 31–53%]) for everolimus and 0% (0 of 39 [0–9%]) for placebo (response rate difference 42% [24–58%]; one-sided Cochran-Mantel-Haenszel test p<0·0001). The most common adverse events in the everolimus and placebo groups were stomatitis (48% [38 of 79], 8% [3 of 39], respectively), nasopharyngitis (24% [19 of 79] and 31% [12 of 39]), and acne-like skin lesions (22% [17 of 79] and 5% [2 of 39]).

INTERPRETATION

Everolimus reduced angiomyolipoma volume with an acceptable safety profile, suggesting it could be a potential treatment for angiomyolipomas associated with tuberous sclerosis.

FUNDING

Novartis Pharmaceuticals.

Nephron-sparing resection of angiomyolipoma after sirolimus pretreatment in patients with tuberous sclerosis

PURPOSE

Renal angiomyolipoma in patients with tuberous sclerosis can cause life-threatening bleeding. Embolization or resection is recommended, but either intervention may result in substantial loss of renal function. Recently, regression of angiomyolipoma size has also been achieved with mTOR inhibitor therapy, but recurrent lesion growth after treatment cessation has to be expected. This is the first report on a multimodal therapeutic approach facilitating a nephron-sparing, definitive resection.

METHODS

Three patients with renal angiomyolipoma not amenable to nephron-sparing surgery were treated with sirolimus aiming trough levels of 4-8 ng/ml. Treatment was well tolerated.

RESULTS

mTOR inhibitor treatment resulted in a regression of angiomyolipoma volume by 38-95 %. Thereafter, nephron-sparing angiomyolipoma resection conserved normal renal function.

CONCLUSION

Neoadjuvant use of mTOR inhibitor pretreatment may represent a novel approach facilitating nephron-sparing resection.

[Guidelines for the management of tuberous sclerosis complex renal disease]

PURPOSE

To review existing literature and deduce guidelines for the management of renal disease in patients with tuberous sclerosis complex (TSC).

PATIENTS

After review of literature, a core panel of five physicians wrote a draft that was evaluated by 14 reviewers who used a 9-level scale (1: total disagreement; 9: total agreement). The guidelines were then reformulated until each item received a median score superior or equal to 8.

RESULTS

Forty-eight to 80 % of TSC patients have significant renal involvement including angiomyolipomas (AMLs), cysts, malignant tumors and renal insufficiency. It is recommended to perform an abdominal ultrasound (and serum creatinine if abnormal ultrasound) when TSC is diagnosed. This work-up will be repeated every 3-5years if normal. Associated autosomal dominant polycystic kidney disease must be suspected in case of numerous and large cysts. After the age of 20, follow-up should use computed tomography (CT) or MRI that are more precise than ultrasound for the measurement of AMLs. Biopsy of a renal mass should be discussed in case of calcifications, necrosis or rapid growth. Females with TSC should undergo screening for pulmonary lymphangioleiomyomatosis by CT at the age of 18, and, if negative at the age of 30-40. Acute bleeding should be treated with percutaneous embolization. Asymptomatic angiomyolipomas with several risk factors (size>80mm, predominant vascular component, micro-aneurysms) should undergo prophylactic treatment, if possible using embolization. The role of mTOR inhibitors in the management of angiomyolipomas needs to be defined.

CONCLUSION

Standardization of follow-up and treatment is necessary to improve the management of TSC renal involvement.

An Australian tuberous sclerosis cohort: are surveillance guidelines being met?

AIM

This study aims to describe the phenotypic and genotypic characteristics of 45 Australian patients with tuberous sclerosis complex (TSC), to assess risk factors for intellectual disability, to compare patients with TSC1 and TSC2 mutations and to assess adherence to surveillance recommendations.

METHODS

Phenotypic features were recorded in 45 patients who fulfilled established criteria for a diagnosis of definite TSC. All patients underwent TSC1 and TSC2 sequencing and multiplex ligand probe amplification. Features were compared in patients with TSC1 mutations versus TSC2 mutations. Recent surveillance was recorded at the point of first contact. Surveillance adherence was compared in the adult and paediatric cohorts.

RESULTS

This cohort consisted of 31 children and 14 adults with definite TSC. The rates of TSC manifestations and TSC1 and TSC2 mutation detection rates were consistent with previous studies. There was a trend towards greater severity for patients with TSC2 mutations compared with their TSC1 counterparts, particularly for autistic spectrum disorder, but this did not reach statistical significance. The presence of seizures was shown to be a risk factor for intellectual disability (P < 0.001). Overall, 12/45 patients (27%) were not undergoing recommended surveillance at the point of first contact. Surveillance guidelines were being followed in 3/31 (11%) children compared with 9/14 (64%) adult patients (P < 0.05).

CONCLUSIONS

The genotypic and phenotypic characteristics of this TSC cohort were consistent with previous studies. Surveillance rates in adult patients were significantly lower than in paediatric patients. This highlights the need for patients with TSC to undergo a focussed transition into adult services.

Clinically relevant imaging in tuberous sclerosis

Tuberous sclerosis (TS), also known as Bourneville disease or Bourneville–Pringle disease, is an autosomal dominant genetic disorder classically characterized by the presence of hamartomatous growths in multiple organs. TS and tuberous sclerosis complex (TSC) are different terms for the same genetic condition. Both terms describe clinical changes due to mutations involving either of the two genes named TSC1 and TSC2, which regulate cell growth. The diagnosis of TSC is established using diagnostic criteria based on clinical and imaging findings. Routine screening and surveillance of patients with TSC is needed to determine the presence and extent of organ involvement, especially the brain, kidneys, and lungs, and identify the development of associated complications. As the treatment is organ specific, imaging plays a crucial role in the management of patients with TSC.

Prophylactic embolization of renal angiomyolipomas: evaluation of therapeutic response using CT 3D volume calculation and density histograms

PURPOSE

To evaluate the efficacy and tolerance of prophylactic embolization of angiomyolipomas (AMLs) and to analyze the therapeutic response by using three-dimensional 3D volume calculation and 3D quantification of fatty and angiomyogenic components during computed tomography (CT) follow-up.

MATERIALS AND METHODS

Over a 51-month period, 30 patients with 34 AMLs (mean diameter, 82 mm ± 37; range, 30-173 mm) underwent 37 prophylactic embolization procedures. The protocol included supraselective arterial embolization with a combination of absolute alcohol, microparticles, and coils. Mean clinical and imaging follow-up were 20.5 and 14.5 months, respectively. The 3D volume calculation and density histograms were retrospectively analyzed for treatment evaluation.

RESULTS

Four technical failures were observed (11%), with one successful secondary reattempt, resulting in 31 AMLs (91.2%) being embolized. Thirty (88.2%) had CT follow-up and were included in the analysis. Embolization was complete after a single procedure for 25 AMLs (83%) and required two procedures in two cases. Three AMLs had incomplete embolization and were scheduled for a second procedure. Mean volume reductions were 43% ± 32 for AMLs followed for 1-6 months after embolization and 81% ± 19 for the 12 AMLs followed for more than 1 year. The volume reduction after embolization was significantly correlated with the AML initial composition, with fat-rich AMLs showing a much smaller reduction of size than predominantly angiomyomatous AMLs (P < .05).

CONCLUSIONS

Prophylactic embolization allows significant reduction of AML volume with a high success rate. Three-dimensional CT volume and density histogram calculations suggest that it is especially effective on angiomyogenic components and fat-poor AMLs.