Kidney damage due to tuberous sclerosis complex: Management recommendations

Kidney transplantation in patients with tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex (TSC) is a disorder of the mammalian target of the rapamycin (mTOR) pathway associated with the development of multisystem tumors, including renal angiomyolipoma (AML). These renal tumors are benign by nature but locally invasive and carry a risk for the progression of chronic kidney disease (CKD) to end stage kidney disease (ESKD). The frequency of subsequent renal transplantation in this population is largely uncharacterized, although single-center data suggests that 5%-15% of adult TSC patients are kidney transplant recipients.

METHODS

This retrospective cohort study utilized United Network for Organ Sharing (UNOS) data. We included candidates waitlisted between 1987 and 2020 for a first kidney transplant with TSC-associated kidney failure. We utilized descriptive statistics to characterize the frequency of first-time kidney transplant waitlisting and transplantation among persons with TSC and the Fine-Gray subdistribution hazard model to evaluate characteristics associated with progression from waitlist.

RESULTS

We identified 200 TSC-associated kidney failure patients within the waitlist cohort. Of these, 12 were pediatric patients. Two-thirds (N = 134) of waitlisted persons were female. One hundred forty patients received a transplant with a median waitlist time of 2 years. Younger age at waitlisting was associated with a greater probability of progressing to transplant (HR 0.98 [95% CI: 0.96-0.99]). 91.8% of kidney transplant recipients survived 1-year post-transplant with a functioning allograft.

CONCLUSIONS

The majority of patients with TSC who are waitlisted for a kidney transplant progress onto transplantation with excellent 1-year post transplant patient and allograft survival.

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

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

Improving care for rare genetic neurodevelopmental disorders: A systematic review and critical appraisal of clinical practice guidelines using AGREE II

PURPOSE

Rare genetic neurodevelopmental disorders associated with intellectual disability require lifelong multidisciplinary care. Clinical practice guidelines may support healthcare professionals in their daily practice, but guideline development for rare conditions can be challenging. In this systematic review, the characteristics and methodological quality of internationally published recommendations for this population are described to provide an overview of current guidelines and inform future efforts of European Reference Network ITHACA (Intellectual disability, TeleHealth, Autism, and Congenital Anomalies).

METHODS

MEDLINE, Embase, and Orphanet were systematically searched to identify guidelines for conditions classified as "rare genetic intellectual disability" (ORPHA:183757). Methodological quality was assessed using the Appraisal of Guidelines, Research, and Evaluation II tool.

RESULTS

Seventy internationally published guidelines, addressing the diagnosis and/or management of 28 conditions, were included. The methodological rigor of development was highly variable with limited reporting of literature searches and consensus methods. Stakeholder involvement and editorial independence varied as well. Implementation was rarely addressed.

CONCLUSION

Comprehensive, high-quality guidelines are lacking for many rare genetic neurodevelopmental disorders. Use and transparent reporting of sound development methodologies, active involvement of affected individuals and families, robust conflict of interest procedures, and attention to implementation are vital for enhancing the impact of clinical practice recommendations.

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

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

Prophylactic renal artery embolization before pregnancy in patients with lymphangioleiomyomatosis and renal angiomyolipoma

OBJECTIVE

Pregnant patients with lymphangioleiomyomatosis (LAM) and renal angiomyolipomas (AMLs) require care for both renal AMLs and pulmonary dysfunction because AMLs can grow and rupture during pregnancy, potentially causing hemorrhagic shock and fetal death. This study examined whether prophylactic transcatheter arterial embolization (TAE) could prevent the pregnancy-associated growth and rupture of renal AMLs in patients with LAM.

METHODS

This retrospective study included five women with 14 renal AMLs (initial diameter, ≥2 cm) first encountered between September 2010 and August 2015 who subsequently became pregnant. Seven tumors in five patients were embolized, and seven tumors in two patients were not treated. Changes in the volume of each tumor were evaluated.

RESULTS

Untreated tumors were much more likely to grow than embolized tumors both during pregnancy (100% vs. 0%) and at the first follow-up visit after delivery (100% vs. 14%). One untreated hypervascular tumor grew rapidly during pregnancy to 409% of the pretreatment volume. No tumor ruptured.

CONCLUSIONS

Prophylactic pre-pregnancy TAE decreased the growth and bleeding of renal AMLs during pregnancy in patients with LAM. TAE can be recommended for hypervascular tumors before pregnancy regardless of the size of the aneurysm.

From kidney injury to kidney cancer

Epidemiologic studies document strong associations between acute or chronic kidney injury and kidney tumors. However, whether these associations are linked by causation, and in which direction, is unclear. Accumulating data from basic and clinical research now shed light on this issue and prompt us to propose a new pathophysiological concept with immanent implications in the management of patients with kidney disease and patients with kidney tumors. As a central paradigm, this review proposes the mechanisms of kidney damage and repair that are active during acute kidney injury but also during persistent injuries in chronic kidney disease as triggers of DNA damage, promoting the expansion of (pre-)malignant cell clones. As renal progenitors have been identified by different studies as the cell of origin for several benign and malignant kidney tumors, we discuss how the different types of kidney tumors relate to renal progenitors at specific sites of injury and to germline or somatic mutations in distinct signaling pathways. We explain how known risk factors for kidney cancer rather represent risk factors for kidney injury as an upstream cause of cancer. Finally, we propose a new role for nephrologists in kidney cancer (i.e., the primary and secondary prevention and treatment of kidney injury to reduce incidence, prevalence, and recurrence of kidney cancer).

Tuberous sclerosis complex: The critical role of the interventional radiologist in management

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous syndrome that is characterised by hamartomas in multiple organs, the characteristic imaging features of which are illustrated in this case report. Angiomyolipoma (AML) is the most common renal manifestation of TSC, which may present with life-threatening haemorrhage at the time of diagnosis. Interventional management with selective renal embolisation is currently the treatment of choice for the safe and effective management of ruptured renal AML.

Clinical applications of digital angiography with the harmonization function in body interventional radiology

Digital subtraction angiography (DSA) is frequently applied in interventional radiology (IR). When DSA is not useful due to misregistration, digital angiography (DA) as an alternative option is used. In DA, the harmonization function (HF) works in real time by harmonizing the distribution of gray steps or reducing the dynamic range; thus, it can compress image gradations, decrease image contrast, and suppress halation artifacts. DA with HF as a good alternative to DSA is clinically advantageous in body IR for generating DSA-like images and simultaneously reducing various motion artifacts and misregistrations caused by patient body motion, poor breath-holding, bowel and ureter peristalsis, and cardiac pulsation as well as halation artifacts often stemming from the lung field. Free-breath DA with HF can improve body IR workflow and decrease the procedure time by reducing the risk of catheter dislocation and using background structures as anatomical landmarks, demonstrating reduced radiation exposure relative to DSA. Thus, HF should be more widely and effectively utilized for appropriate purposes in body IR. This article illustrates the basic facts and principles of HF in DA, and demonstrates clinical advantages and limitations of this function in body IR.

Efficacy and safety of low-dose everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex

BACKGROUND

The aim of this study was to evaluate the safety and efficacy of low-dose everolimus treatment in patients with tuberous sclerosis complex (TSC)-associated angiomyolipoma (AML) with renal dysfunction or low body weight.

METHODS

We investigated a total of 50 adult patients underwent everolimus treatment for AML associated with TSC. For patients with renal dysfunction (serum creatinine level ≥ 1.5 mg/dl) or low body weight (body weight < 35 kg), 5 mg of everolimus was administered daily (low-dose group). For patients without renal dysfunction or low body weight, 10 mg of everolimus was administered daily (conventional-dose group). The treatment effects and adverse events were compared between the two groups.

RESULTS

There were 20 patients in the low-dose group, and 30 in the conventional-dose group. The average reduction rate of the AML volume in the low-dose group was 52%, whereas it was 60% in the conventional-dose group. No significant differences were found in the average reduction rate between the groups (P = 0.24). The average blood everolimus trough levels were 7.7 ± 3.1 ng/mL in the low-dose group and 12.2 ± 5.7 ng/mL in the conventional-dose group. The level was significantly higher in the conventional-dose group than in the low-dose group (P = 0.004). The incidences of stomatitis and irregular menstruation were significantly lower in the low-dose group than in the conventional-dose group (P = 0.009, P = 0.045, respectively).

CONCLUSIONS

The present study demonstrates that low-dose everolimus treatment is safe and effective for TSC-associated AML. This treatment was well tolerated and adverse events were mild in all cases.

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.

Effect of everolimus treatment for regrown renal angiomyolipoma associated with tuberous sclerosis complex after transcatheter arterial embolization

BACKGROUND

The aim of this study was to evaluate the effects and the utility of second-line everolimus treatment for regrown renal angiomyolipoma (AML) with tuberous sclerosis complex (TSC) after transcatheter arterial embolization (TAE).

METHODS

We investigated a total of 14 patients who underwent second-line everolimus treatment for TSC-AML that regrew after TAE, and assessed their effects and adverse events. Everolimus treatment was performed for AML with a maximum diameter of 4 cm. To determine the reduction ratio of AML, the volume of AML was measured using multislice helical computed tomography. Adverse events were evaluated according to CTCAE v4.0-JCOG. We further compared the treatment effect and adverse events with those in patients receiving first-line everolimus treatment.

RESULTS

The AML volume decreased in all patients, with a ≥ 50% volume decrease in 57% (8 of 14) of the cases, and the mean reduction rate was 53%. We observed no significant difference in the mean reduction rate of AML between second-line everolimus treatment for regrown TSC-AML after TAE and first-line everolimus treatment for TSC-AML. The adverse events were mild and consistent with those reported in our previous study.

CONCLUSION

Although further studies are needed, everolimus appears to be effective as second-line treatment for TSC-AML that regrew after TAE and a beneficial treatment option for TSC-AML.

Genotype-phenotype correlation of patients with tuberous sclerosis complex-associated renal angiomyolipoma: a descriptive study

TSC2 gene mutation was repeatedly reported to be associated with a more severe phenotype in patients with tuberous sclerosis complex (TSC). Our current study aims to further explore whether there is such a correlation in patients with TSC-associated renal angiomyolipoma (TSC-RAML). TSC1/TSC2 gene mutation was screened by high-throughput sequencing in 25 TSC-RAML patients from 2 medical centers. Clinical data were also carefully collected. Linear regression analysis and Student t-test were conducted by IBM SPSS Statistics Version 21.0 to analyze the genotypic-phenotypic relationship. The results indicated a high level of TSC gene mutation (80%; 20/25) in TSC-RAML patients, with higher frequency of TSC2 mutation (68%; 17/25) than TSC1 mutation (12%; 3/25). Seven novel mutation sites were detected in this study. In general, there were no significant correlations between tumor size and age (r = 0.134, P = .522), hemoglobin (r = 0.255, P = .219), and serum creatinine (r = 0.043, P = .839). Patients with larger tumor size have higher risk of bleeding. Specially, it was higher hemoglobin level in patients with TSC1 mutation than ones with TSC2 mutation and without TSC mutation (P < .05). However, no difference was found in either tumor size or serum creatinine by TSC mutation genes (P > .05). Furthermore, no difference was found in tumor size, hemoglobin, and serum creatinine by TSC mutation types (P > .05). In conclusion, TSC-RAML is TSC2 mutation dominant, with the individual differences varying greatly. No definite genotype-phenotype correlation exists in patients with TSC-RAML, and it needs to be further explored.

Burden of renal angiomyolipomas associated with tuberous sclerosis complex: results of a patient and caregiver survey

Background

Tuberous sclerosis complex (TSC) is a rare genetic disorder characterized by benign tumors in multiple organs, including non-cancerous kidney lesions known as renal angiomyolipomas. This study’s objective is to describe the age-stratified morbidity, treatment patterns, and health-related quality of life of TSC patients with renal angiomyolipomas in the United States. A cross-sectional, anonymous web-based survey was conducted with a convenience sample of TSC patients and caregivers identified through a patient advocacy organization.

Results

Out of the total sample of 676, 182 respondents reported having kidney complications with 33% of the pediatric group and 25% of the adult group with TSC reporting them. Of those with kidney complications, 110 (60%) reported a diagnosis of renal angiomyolipomas, of which 79 (72%) were adult patients and 31 (28%) were pediatric age patients. Eighty-four percent of the pediatric group and 76% of the adult group reported lesions on both kidneys. Of the patients experiencing involvement of only one kidney, 60% of the pediatric group and 21% of the adult group reported having multiple tumors within the affected kidney. Almost all of the sample (99%) reported seeing a physician and having a procedure or test for TSC in the past year. Less than half the respondents (44%) reported being hospitalized in the past year. Thirty-nine percent reported an emergency room visit as well. Compared to scores for patients with kidney disease, the angiomyolipoma adult patients reported significantly lower Mental Component Summary scores on the SF-12.

Conclusions

Renal angiomyolipomas burden leads to frequent healthcare resource use including hospitalization, invasive treatments, and surgical procedures, which result in an impaired mental health related quality of life.

Renal manifestations of tuberous sclerosis complex: patients' and parents' knowledge and routines for renal follow-up - a questionnaire study

BACKGROUND

Renal angiomyolipomas (AMLs) are a major clinical feature in patients with tuberous sclerosis complex (TSC). Spontaneous bleeding can be life threatening, and appropriate information and proper surveillance and management are important to limit morbidity and mortality. Because TSC is a rare disease, patients are at risk of suboptimal medical management. Our aim was to investigate patients' and parents' knowledge about renal angiomyolipomas (AMLs) in Tuberous Sclerosis Complex (TSC) and to identify current routines for renal follow-up.

METHODS

A questionnaire survey was initiated by the French Reference Centre on TSC. It was distributed in France through university hospitals and the patients' association (2009-2011), and to patients registered by the Norwegian National Centre for Rare Epilepsy-Related Disorders (2013-2014). Contingency tables with Chi-Square test for independence (with Yates Continuity Correction) and Pearson-Chi-Square value were used for correlation statistics.

RESULTS

We included 357 patients (France, n=257; Norway n=100). Most participants knew that TSC is associated with AMLs. However, 42 % did not know about the risk of AMLrelated bleeding, and 37 % had been informed about the risk of bleeding only after the age of 15 years. Furthermore, 14 % did not know whether they themselves or their child had AMLs. Patients had less knowledge than parents. Medical consultations and patient associations were the main sources of information. Among 30 % of patients, renal imaging was not received at all, or not conducted every 1-3 years, as recommended by current guidelines. Regular imaging was more frequent in patients with AMLs < 15 years, than in patients with AMLs ≥ 15 years. Ultrasound was the most frequently used imaging modality.

CONCLUSIONS

Knowledge of renal AML in TSC patients and their parents was lower than expected, and follow-up by renal imaging was suboptimal for a substantial proportion of patients. Patients and parents should be informed about the risk and symptoms of renal bleeding, at the latest when the patient is 15 years. Monitoring the growth of AMLs should be standardized to comply with guidelines. Transition between adolescence and adulthood is a high-risk period and ensuring appropriate follow-up at this time is particularly important.

Effect of everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex: an evaluation based on tumor density

BACKGROUND

The aim of this study was to evaluate the influence of components of angiomyolipoma (AML) on the efficacy of everolimus.

METHODS

We investigated a total of 40 patients with tuberous sclerosis complex (TSC) who had AML ≥4 cm in diameter. The components of the AML were determined using abdominal computed tomography (CT) images. The AML density was measured as the mean Hounsfield unit (HU) values of the whole area of the AML on axial CT images. We classified them into two groups, i.e., a lipid group with a predominant lipid component (HU ≤ -50) and a solid group with predominant vascular and muscle components (HU ≥30). For each patient, we measured the AML reduction rate and transition of the mean HU value.

RESULTS

The mean reduction rate of AML in the lipid group was 24%, whereas it was 68% in the solid group (P < 0.001). The mean tumor density after 6 months was decreased in both groups. In particular, the density significantly decreased compared to the baseline in the solid group (P < 0.001). The tumor density did not change after 6 months in either group.

CONCLUSION

The effect of everolimus on TSC-AML is mainly a reduction of the solid components consisting of angioma and leiomyoma. The tumor density at the start of treatment might be a predictive marker for the response to everolimus in TSC-AML.

Rapamycin therapy for neonatal tuberous sclerosis complex with cardiac rhabdomyomas: A case report and review

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease that varies greatly in its expression. The current study reports a novel case of TSC caused by a TSC2 mutation (TSC2c.1642_1643insA or TSC2p.K549fsX589), in which multiple cardiac rhabdomyomas were detected by fetal echocardiography in week 31 of pregnancy. The infant was delivered successfully; however, seizures began 16 days following birth. Subsequent genetic tests confirmed a diagnosis of TSC. Rapamycin treatment resulted in regression of cardiac rhabdomyomas and controlled seizures. The current study demonstrates the value of fetal echocardiography in the diagnosis of TSC and suggests that inhibition of the mammalian target of the rapamycin (mTOR) signaling pathway may be considered as a potential antiepileptogenic therapy for neonatal TSC. In addition, it was demonstrated that rapamycin treatment was therapeutically beneficial for preventing disorders caused by abnormal mTOR signaling, such as cancer. According to the literature, cardiac rhabdomyomas, seizures and skin lesions are well established markers for TSC in neonates. MRI scans of the brain and genetic screening of TSC1 and TSC2 genes may facilitate an early diagnosis of TSC.

Intermittent everolimus administration for renal angiomyolipoma associated with tuberous sclerosis complex

OBJECTIVES

To evaluate the effects and utility of intermittent everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex.

METHODS

We investigated a total of 26 patients with tuberous sclerosis complex who had angiomyolipoma ≥4 cm in diameter. For each patient, we analyzed the reduction in the size of the angiomyolipoma, the change in size after everolimus withdrawal, the size reduction rate on everolimus readministration and adverse events caused by everolimus. The volume of angiomyolipoma was measured using abdominal computed tomography or magnetic resonance imaging. Adverse events were evaluated according to CTCAE v4.0-JCOG.

RESULTS

The average size reduction rate of angiomyolipoma in the initial treatment with everolimus was 67%. Eight patients (31%) did not have enlarged angiomyolipoma after everolimus withdrawal. The other 18 patients (69%) restarted everolimus treatment because of enlargement of the angiomyolipoma. The average size reduction rate of angiomyolipoma in the everolimus retreatment group was 61%, which was equivalent to the rate for the initial treatment. There were fewer adverse events during everolimus retreatment than in the initial treatment.

CONCLUSIONS

This is the first report regarding intermittent everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex. This treatment is effective for tumor control and adverse event management. This beneficial treatment option for patients can minimize the drug dosage and the occurrence of adverse events.

Recommendations for imaging-based diagnosis and management of renal angiomyolipoma associated with tuberous sclerosis complex

Renal angiomyolipomas are found in up to 80% of tuberous sclerosis complex (TSC) patients. Although these tumours are usually asymptomatic, lesions >3 cm in diameter are prone to bleeding and up to 10% of TSC patients may experience a massive and potentially fatal retroperitoneal haemorrhage. Diagnosis can be complicated because of the initial lack of symptoms and the fat-poor content of atypical renal angiomyolipomas. After diagnosis, tumour growth and the emergence of new tumours must be monitored. Treatment with mammalian target of rapamycin (mTOR) inhibitors can reduce tumour size and is indicated in patients with TSC-associated renal angiomyolipomas >3 cm in diameter. Imaging-based assessment of kidney disease is essential to the diagnosis and management of patients with TSC. The aims of imaging studies in this context are to detect and characterize tumours, assess and detect the risk of complications and evaluate the response to treatment, especially in patients treated with mTOR inhibitors. A multidisciplinary expert panel developed a series of recommendations based on current evidence and professional experience for imaging studies in adults and children with TSC-associated renal angiomyolipoma. The recommendations cover radiological diagnosis and follow-up of the classic and atypical or fat-poor TSC-associated renal angiomyolipomas, biopsy indications, minimal requirements for radiological requests and reports and recommended technical features and protocols for computed tomography and magnetic resonance imaging.

Natural history of patients with tuberous sclerosis complex related renal angiomyolipoma

OBJECTIVE

To examine temporal relationships between tuberous sclerosis complex (TSC) and renal angiomyolipoma diagnosis and outcomes, treatment, and healthcare utilization.

METHODS

Administrative data from the MarketScan Commercial Database was used to select TSC-related renal angiomyolipoma patients during 1 January 2000-31 March 2013. Patients were followed until the earliest of inpatient death or end of enrollment or study. Occurrence of kidney-related outcomes, kidney-related procedures, and all-cause healthcare utilization and time to occurrence were reported. Kaplan-Meier curves were used to display the unadjusted distribution of time to outcome.

RESULTS

A total of 605 patients were selected (<18 years N = 225; ≥18 years N = 380). Mean time from TSC to renal angiomyolipoma diagnosis was 25.7 months in younger and 16.9 months in older patients. Patients ≥18 years had higher rates of chronic kidney disease (CKD), hematuria, kidney failure, embolization (EMB), and partial and complete nephrectomy compared to patients <18 years (all p < .05). Mean time from TSC-related renal angiomyolipoma diagnosis to CKD, hematuria, kidney failure, EMB, first emergency room and inpatient visits was shorter in older compared to younger patients (all p < .05). Probability of developing CKD was approximately 0.8 and 0.95 within 3 years in younger and older patients, respectively.

CONCLUSIONS

Patients with TSC-related renal angiomyolipoma had high rates of kidney-related outcomes and procedures. These events sometimes preceded the angiomyolipoma diagnosis. A key study limitation was that due to the small sample size, results may have been biased by outliers. Research is needed to determine whether earlier angiomyolipoma diagnosis can impact occurrence of events and reduce healthcare utilization.

Prevalence of Renal Angiomyolipomas and Spontaneous Bleeding Related to Angiomyolipomas in Tuberous Sclerosis Complex Patients in France and Norway-a Questionnaire Study

OBJECTIVE

To estimate the prevalence of renal angiomyolipomas (AMLs) and AML-related bleedings among patients with tuberous sclerosis complex and to gather information about associated treatments.

METHODS

A questionnaire survey was undertaken by the French Reference Centre for Tuberous Sclerosis Complex and distributed through university hospitals and the patients' association (2009-2011). The questionnaire was then distributed to patients registered by the Norwegian National Centre for Rare Epilepsy-Related Disorders (2013-2014). Risk of bleeding was estimated by Kaplan-Meier analysis.

RESULTS

We included 357 patients (France, n = 257; Norway, n = 100); 189 (54%) reported having AMLs, 111 (32%) reported not having AMLs, and 50 (14%) reported not knowing whether they had AMLs. Twenty-five patients (France, n = 19; Norway, n = 6) reported that they have had bleeding. Age at first bleeding (known in 22 patients) was 27.6 ± 8.5 years. Fifteen patients (France, n = 11; Norway, n = 4) experienced first bleeding between 20 and 30 years. Bleeding-free survival was similar in France and Norway (P = .471). The bleeding-free survival rate at 72 years was 81% (95% confidence interval: 68-89) in the overall population and 66% (95% confidence interval: 43-82) in patients with AMLs. Bleeding treatment (known in 24 patients) consisted of conservative measures (n = 9), embolization (n = 8), nephrectomy (n = 4), embolization and nephrectomy (n = 2), or partial nephrectomy (n = 1). Fifteen French patients reported prophylactic treatment. In Norway, this information was known only in patients with renal bleeding and was reported in two.

CONCLUSION

Fifty-four percent of the patients reported having AMLs and 7% (25/357) reported bleeding. Sixty-eight percent of first bleedings occurred between 20 and 30 years. Bleedings were managed conservatively in 38% of the patients and 62% needed active treatment.

Assessment of Tuberous Sclerosis Complex Associated With Renal Lesions by Targeted Next-generation Sequencing in Mainland China

OBJECTIVE

To identify the TSC1 and TSC2 mutations in patients with tuberous sclerosis complex (TSC) associated with renal lesions, and to explore the relationship between genotypes and phenotypes.

MATERIALS AND METHODS

We analyzed 43 individuals affected with TSC accompanied by renal lesions using next-generation sequencing (NGS). We also performed Sanger sequencing to validate the NGS results.

RESULTS

We reported a comprehensive mutation analysis of 43 affected individuals with TSC accompanied by renal lesions using NGS. Forty-one of 43 patients (95%) had at least 1 detectable mutation in the TSC1 or TSC2 gene. We identified 14 novel nucleotide alterations, including 11 novel small mutations and 3 large-deletion mutations for the first time. Our study showed that patients with TSC2 mutations had higher frequency of hypomelanotic macules and dental enamel pits and larger angiomyolipomas (AMLs) than patient populations with non-TSC2 mutations through analysis of the correlated mutation findings with clinical features.

CONCLUSION

In conclusion, patients with TSC2 mutations had higher frequency of hypomelanotic macules and dental enamel pits, along with larger renal AMLs, compared with patient populations with non-TSC2 mutations. Patients with large deletions and frameshift mutations of the TSC1 or TSC2 gene showed larger AML diameters than patients with other kinds of mutations.

Outcomes of everolimus treatment for renal angiomyolipoma associated with tuberous sclerosis complex: A single institution experience in Japan

OBJECTIVES

To evaluate the efficacy and toxicity profiles of everolimus in Japanese patients with renal angiomyolipoma associated with tuberous sclerosis complex.

METHODS

Patients with a 4-cm or larger angiomyolipoma meeting the diagnostic criteria of tuberous sclerosis complex were selected as participants of our investigation. In each case, we assessed tuberous sclerosis complex-associated symptoms, the treatment effect and adverse events. The treatment effect was evaluated by measuring the tumor volume reduction rate using abdominal computed tomography or magneitc resonance imaging. Adverse events were investigated using CTCAE v4.0-JCOG. The dose of everolimus was set at 10 mg once a day for adults. For childhood angiomyolipoma, everolimus administration was initiated at a dose of 5 mg once a day. Blood everolimus level was measured, and the dose was adjusted to maintain this within a range of 5-15 ng/mL.

RESULTS

The angiomyolipoma volume decreased in 46 of 47 cases, and the mean reduction rate for all cases was 60% in 12 months. The angiomyolipoma volume markedly decreased in the first 3 months, and the size leveled off after 6 months. The main adverse events related to everolimus treatment were stomatitis (91%) and irregular menstruation (65%). Grade 3 or severer adverse events were noted in three cases (6%). All patients developed some adverse events in the first 6 months. The incidence markedly decreased to 40-50% after 13 months.

CONCLUSION

The tumor volume-reducing effect of everolimus in a Japanese population was equivalent to or higher than that in Western populations. A wide variety of everolimus treatment-related adverse events can be observed, but most cases are very mild. Special attention should be given to stomatitis, irregular menstruation and interstitial lung disease as adverse events.

Evidence Supporting a Lymphatic Endothelium Origin for Angiomyolipoma, a TSC2(-) Tumor Related to Lymphangioleiomyomatosis

Angiomyolipoma (AML) is a tumor closely related to lymphangioleiomyomatosis (LAM). Both entities are characterized by the proliferation of smooth muscle actin and melanocytic glycoprotein 100 (recognized by antibody HMB-45)-positive spindle-shaped and epithelioid cells. AML and LAM are etiologically linked to mutations in the tsc2 and tsc1 genes in the case of LAM. These genes encode the proteins tuberous sclerosis complex (TSC)-1 and TSC2, which are directly involved in suppressing the mechanistic target of rapamycin cell growth signaling pathway. Although significant progress has been made in characterizing and pharmacologically slowing the progression of AML and LAM with rapamycin, our understanding of their pathogenesis lacks an identified cell of origin. We used an AML-derived cell line to determine whether TSC2 restitution brings about the cell type from which AML arises. We found that AML cells express lymphatic endothelial cell markers consistent with lymphatic endothelial cell precursors in vivo and in vitro. Moreover, on TSC2 correction, AML cells mature into adult lymphatic endothelial cells and have functional attributes characteristic of this cell lineage, suggesting a lymphatic endothelial cell of origin for AML. These effects are dependent on TSC2-mediated mechanistic target of rapamycin inactivation. Finally, we demonstrate the in vitro effectiveness of norcantharidin, a lymphangiogenesis inhibitor, as a potential co-adjuvant therapy in the treatment of AML.

Long-term Clinical Morbidity in Patients With Renal Angiomyolipoma Associated With Tuberous Sclerosis Complex

OBJECTIVE

To estimate the incidence rates of kidney-related clinical outcomes among patients with tuberous sclerosis complex (TSC)-related angiomyolipoma (AML) compared to an age-matched control cohort in the United States.

MATERIALS AND METHODS

This was a retrospective, observational study. Administrative data from the MarketScan Research Databases were used to select patients with TSC and renal AML. An age-matched group with no TSC or renal AML was identified for comparison. Outcomes were incidence rates per 100 patient-years and number of months to development of hematuria, chronic kidney disease, renal hemorrhage, kidney failure, and inpatient death.

RESULTS

Among the commercially insured TSC-renal AML patients (N = 605) and matched controls (N = 1815), 37.2% were <18 years old. Among Medicaid TSC-renal AML patients (N = 246) and matched controls (N = 738), 38.6% were aged <18. In the commercial sample, in both age groups (<18 and ≥18), the incidence rate of each clinical outcome measured was higher in the TSC-renal AML cohort than in the control cohort, with several differences reaching statistical significance. Compared with younger patients, older TSC-renal AML patients had higher incidence rates of clinical outcomes (hematuria: 20.4 vs 8.7; chronic kidney disease: 9.6 vs 3.5; renal hemorrhage 2.7 vs 0.7; kidney failure: 1.9 vs 0.4) and took less time on average to develop each clinical outcome. A similar pattern of results was observed among patients with Medicaid insurance.

CONCLUSION

TSC-renal AML patients are at significantly higher risk for renal morbidity relative to the general population.

Microaneurysms in renal angiomyolipomas: Can clinical and computed tomography features predict their presence and size?

PURPOSE

To evaluate clinical and multidetector computed tomography (MDCT) features associated with the presence and size of microaneurysms in renal angiomyolipomas (AMLs).

MATERIALS AND METHODS

The MDCTs and digital subtraction angiographies (DSAs) of 31 patients who had further percutaneous arterial embolization of AMLs were retrospectively reviewed. They were 22 women and 9 men (mean age, 47.7±27.7 years). The medical files of the included patients were reviewed for age, gender and clinical features. MDCT and DSA images were analyzed by two readers working in consensus.

RESULTS

Of the 31 patients, 15 had tuberous sclerosis complex (TSC) or lymphangioleiomyomatosis (LAM). In total, the 31 patients had 54 AMLs (5 ruptured). On DSA, 28 clusters of microaneurysms were found in 17 patients (21 AMLs). Four of the five ruptured AMLs had microaneurysms. None of the 12 AMLs≤40mm and 21 of the 42 AMLs>40mm had microaneurysms. Among AMLs>40mm, history of TSC/LAM (P=0.5), RENAL score (P=0.7) and relative volume of fat (P=0.11) did not significantly predict the presence of microaneurysms. Microaneurysms were significantly larger in ruptured (9.5±5.7mm) than non-ruptured (3.9±1.9mm, P=0.02) AMLs. No associations were found between the size of microaneurysms and the size of AMLs.

CONCLUSION

Microaneurysms were found in no AML ≤40mm and in 50%of AMLs>40mm. In AMLs >40mm, history of TSC/LAM, RENAL score and relative volume of fat did not significantly predict the presence of microaneurysms.

Rates of interventional procedures in patients with tuberous sclerosis complex-related renal angiomyolipoma

OBJECTIVE

To describe rates of renal artery embolization, partial nephrectomy, and complete nephrectomy in patients with tuberous sclerosis complex (TSC) and renal angiomyolipoma.

METHODS

Data from the MarketScan® Research Databases were used to select patients with TSC and renal angiomyolipoma during January 1, 2000-March 31,2013 (Commercial database) and January 1, 2000-June 30, 2012 (Medicaid database). Patients had at least 30 days of follow-up and were followed until the earliest of inpatient death, end of enrollment, or end of study. Rates of embolization and nephrectomy were calculated.

RESULTS

In total, 218 patients <18 years (mean = 9.7 years) and 378 patients ≥18 years (mean 36.9 years) were selected from the Commercial database. Fifty-nine patients <18 years (mean = 7.2 years) and 117 patients ≥18 years (mean = 37.2 years) were selected from the Medicaid database. Follow-up in the Medicaid cohorts was approximately twice that of the Commercial cohorts. Among patients in the study, 24.2% had at least one interventional procedure: 15.2% had embolization, 5.2% had partial nephrectomy, and 7.6% had complete nephrectomy. Within the Commercial cohort ≥18 years, 18.5% had embolization, 7.7% had partial nephrectomy, and 11.4% had complete nephrectomy. Corresponding percentages in the Medicaid adult cohort were 17.1%, 5.1%, and 4.3%. Repeat embolization procedures occurred in up to 7.7% of Commercial patients and in up to 6.8% of Medicaid patients. Repeat partial nephrectomy occurred in up to 4.5% and 1.7% of Commercial and Medicaid patients, respectively.

CONCLUSIONS

Approximately 25% of patients with TSC-renal angiomyolipoma experienced embolization or nephrectomy, with some patients undergoing repeat procedures. Study limitations included small sample sizes, the majority of the study period occurred prior to the approval of mammalian target of rapamycin inhibitors for the treatment of TSC-renal AML, and results may not be generalizable to patients with insurance other than commercial or Medicaid.

Kidney involvement in tuberous sclerosis complex: the impact on healthcare resource use and costs

OBJECTIVE

Tuberous sclerosis complex (TSC) is associated with non-malignant kidney lesions-angiomyolipomata-that may be associated with chronic kidney disease (CKD). This study investigated the relationship between renal angiomyolipomata and CKD in TSC, including the impact on healthcare resource utilization (HCRU) and costs.

METHODS

This was a retrospective, longitudinal cohort study based on medical record data spanning January 1990-April 2012 for 369 TSC patients treated at a specialty center in the Netherlands. Cohorts were established based on CKD stage and angiomyolipoma size. Rates of HCRU (physician visits, monitoring, and interventions) were compared across cohorts using rate ratios. Healthcare costs were compared across cohorts using cost differences. Regression models were used to identify predictive factors for HCRU and healthcare costs.

RESULTS

Sixteen per cent of patients reached CKD stage 3 or higher during follow-up. Patients at more advanced stages of CKD more frequently had either large or multiple small angiomyolipomata and higher HCRU rates and healthcare costs. In the multivariate analyses, male gender, CKD stage >1, angiomyolipoma size ≥3.5 cm, embolization, and the presence of moderate or severe lymphangioleiomyomatosis (LAM) were associated with greater HCRU (p ≤ 0.002 for all comparisons). Definite (vs suspected) TSC diagnosis, CKD stage 5 (vs CKD stage 1), angiomyolipoma size ≥3.5 cm, and moderate or severe LAM were associated with higher costs (p = 0.050 for TSC diagnosis, p ≤ 0.002 for other comparisons). Costs in CKD stage 5 were driven primarily by dialysis.

CONCLUSIONS

A substantial proportion of patients with TSC developed moderate-to-severe CKD, which was associated with renal angiomyolipomata and increased HCRU and costs.

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.

Angiomyolipoma of the thoracic wall: an extremely rare diagnostic challenge

Extrarenal angiomyolipoma (AML) is an extremely uncommon lesion, accounting for less than 9% of all angiomyolipomas. We present a previously unreported case of a rarely located gigantic extrarenal angiomyolipoma at the posterolateral chest wall of a 35-year-old woman. Clinically, the lesion had all the characteristics of a benign tumor, being soft in palpation, painless, and growing in size in a slow rate. Histologically, the lesion consisted of convoluted thick-walled blood vessels without an elastic layer, interlacing fascicles of smooth muscle, and mature adipose tissue, features consistent with an angiomyolipoma. The mass was surgically removed, without any postoperative complications, and the patient has an uneventful postoperative course. Signs of local recurrence have not been observed. The purpose of this brief report is to point out the necessity of including angiomyolipoma in the differential diagnosis of adipose layer lesions.