Tuberous sclerosis complex renal disease

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Healthcare utilization and costs in patients with tuberous sclerosiscomplex-related renal angiomyolipoma

OBJECTIVE

To quantify healthcare utilization and costs in patients with tuberous sclerosis complex (TSC) and renal angiomyolipoma (AML) in a matched cohort of patients without TSC or AML.

METHODS

Administrative data from the MarketScan Research Databases were used to select patients with TSC and renal AML during January 1, 2000-March 31, 2013 from the Commercial database and January 1, 2000-June 30, 2012 from the Medicaid database. Patients were required to have at least 30 days of follow-up from initiation into the study, and were followed until inpatient death, end of insurance coverage, or the end of study. Age, calendar year, and payer-matched controls that had no TSC and no AML were selected. All-cause annualized healthcare utilization and costs were calculated by service category.

RESULTS

A total of 218 patients under 18 years and 377 patients 18 years and older with TSC-renal AML were selected from the Commercial database, and matched to 654 and 1,131 controls, respectively. Thirty-eight patients under 18 years and 110 patients 18 years or older with TSC-renal AML were selected from the Medicaid database, and matched to 54 and 212 controls, respectively. Within the Commercial cohort, and across both age groups, TSC-renal AML patients utilized more healthcare services than their matched controls. Within the Medicaid cohort, in both age groups, utilization was higher in TSC-renal AML patients vs control patients for inpatient admissions, emergency room visits, physician office visits, and hospital-based outpatient visits. Across age groups and in both the Commercial and Medicaid cohorts, the annual average total costs were significantly higher in TSC-renal AML patients compared to control patients (p < 0.05 for all). Healthcare costs ranged from $29,240-$48,499 for TSC-renal AML patients and from $2,082-$10,864 for control patients.

CONCLUSIONS

Compared to controls, TSC-renal AML patients incurred substantially higher annual healthcare utilization and costs.

TSC1 and TSC2 gene mutations and their implications for treatment in Tuberous Sclerosis Complex: a review

Tuberous sclerosis complex is an autosomal dominant disorder characterized by skin manifestations and formation of multiple tumors in different organs, mainly in the central nervous system. Tuberous sclerosis is caused by the mutation of one of two tumor suppressor genes, TSC1 or TSC2. Currently, the development of novel techniques and great advances in high-throughput genetic analysis made mutation screening of the TSC1 and TSC2 genes more widely available. Extensive studies of the TSC1 and TSC2 genes in patients with TSC worldwide have revealed a wide spectrum of mutations. Consequently, the discovery of the underlying genetic defects in TSC has furthered our understanding of this complex genetic disorder, and genotype-phenotype correlations are becoming possible, although there are still only a few clearly established correlations. This review focuses on the main symptoms and genetic alterations described in TSC patients from 13 countries in three continents, as well as on genotype-phenotype correlations established to date. The determination of genotype-phenotype correlations may contribute to the establishment of successful personalized treatment for TSC.

Manifestations of Tuberous Sclerosis Complex: The Experience of a Provincial Clinic

BACKGROUND

Tuberous sclerosis complex (TSC) is a neurocutaneous disorder with a wide spectrum of manifestations. Recent consensus recommendations stress the importance of multidisciplinary management of children with TSC. The objective of this study was to examine the manifestations of TSC at a large referral centre to determine the care needs of this population.

METHODS

A retrospective, systematic chart review was performed of children with TSC managed at British Columbia Children's Hospital. Patients were identified through epilepsy and clinical neurophysiology databases.

RESULTS

The study population comprised 81 patients, born between 1987 and 2014, who were a median of 10 years (range, 0.2-23.2) at most recent follow-up. Epilepsy occurred in 91% of patients, including 32% with a history of infantile spasms. Nineteen patients underwent epilepsy surgery, nine (47%) of whom were seizure-free at most recent follow-up. Overall, 61% of epilepsy patients had been seizure-free for at least 1 year at the time of last follow-up. Neuropsychiatric disorders were diagnosed in 49% of children, with autism (25%), attention deficit hyperactivity order (19%) and anxiety (16%) being the most common. Cardiac rhabdomyomata occurred in 35% of children and renal angiomyolipomas were seen in 43%. A total of 91% had skin manifestations.

CONCLUSION

This study outlines the multisystem manifestations of TSC, observed through a large pediatric referral center. Epilepsy and neuropsychiatric disorders are the major source of morbidity in this age group and provide many challenges to the treating clinician. Because a subset of the study population is still quite young, the prevalence of neuropsychiatric disorders is likely underestimated.

TuberOus SClerosis registry to increase disease Awareness (TOSCA) - baseline data on 2093 patients

Background

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder. Many gaps remain in the understanding of TSC because of the complexity in clinical presentation. The TuberOus SClerosis registry to increase disease Awareness (TOSCA) is an international disease registry designed to address knowledge gaps in the natural history and management of TSC. Here, we present the baseline data of TOSCA cohort.

Methods

Patients of any age diagnosed with TSC, having a documented visit for TSC within the preceding 12 months, or newly diagnosed individuals were included. The registry includes a “core” section designed to record detailed background information on each patient including disease manifestations, interventions, and outcomes collected at baseline and updated annually. “Subsections” of the registry recorded additional data related to specific features of TSC.

Results

Baseline “core” data from 2093 patients enrolled from 170 sites across 31 countries were available at the cut-off date September 30, 2014. Median age of patients at enrollment was 13 years (range, 0–71) and at diagnosis of TSC was 1 year (range, 0–69). The occurrence rates of major manifestations of TSC included – cortical tubers (82.2%), subependymal nodules (78.2%), subependymal giant cell astrocytomas (24.4%), renal angiomyolipomas (47.2%), lymphangioleiomyomatosis (6.9%), cardiac rhabdomyomas (34.3%), facial angiofibromas (57.3%), forehead plaque (14.1%), ≥ 3 hypomelanotic macules (66.8%), and shagreen patches (27.4%). Epilepsy was reported in 1748 (83.5%) patients, of which 1372 were diagnosed at ≤ 2 years (78%). Intellectual disability was identified in 451 (54.9%) patients of those assessed. TSC-associated neuropsychiatric disorders (TAND) were diagnosed late, and not evaluated in 30–50% of patients.

Conclusion

TOSCA is the largest clinical case series of TSC to date. It provided a detailed description of the disease trajectory with increased awareness of various TSC manifestations. The rates of different features of TSC reported here reflect the age range and referral patterns of clinics contributing patients to the cohort. Documentation of TAND and LAM was poor. A widespread adoption of the international TSC assessment and treatment guidelines, including use of the TAND Checklist, could improve surveillance. The registry provides valuable insights into the necessity for monitoring, timing, and indications for the treatment of TSC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0553-5) contains supplementary material, which is available to authorized users.

Genetic Syndromes Affecting Kidney Development

Renal anomalies are common birth defects that may manifest as a wide spectrum of anomalies from hydronephrosis (dilation of the renal pelvis and calyces) to renal aplasia (complete absence of the kidney(s)). Aneuploidies and mosaicisms are the most common syndromes associated with CAKUT. Syndromes with single gene and renal developmental defects are less common but have facilitated insight into the mechanism of renal and other organ development. Analysis of underlying genetic mutations with transgenic and mutant mice has also led to advances in our understanding of mechanisms of renal development.

The Role of mTOR Inhibitors in the Treatment of Patients with Tuberous Sclerosis Complex: Evidence-based and Expert Opinions

Tuberous sclerosis complex (TSC) is a genetic disorder arising from mutations in the TSC1 or TSC2 genes. The resulting over-activation of the mammalian target of rapamycin (mTOR) signalling pathway leaves patients with TSC susceptible to the growth of non-malignant tumours in multiple organs. Previously, surgery was the main therapeutic option for TSC. However, pharmacological therapy with mTOR inhibitors such as everolimus and sirolimus is now emerging as an alternate approach. Everolimus and sirolimus have already been shown to be effective in treating subependymal giant cell astrocytoma (SEGA) and renal angiomyolipoma (AML), and everolimus is currently being evaluated in treating TSC-related epilepsy. In November 2013 a group of European experts convened to discuss the current options and practical considerations for treating various manifestations of TSC. This article provides evidence-based recommendations for the treatment of SEGA, TSC-related epilepsy and renal AML, with a focus on where mTOR inhibitor therapy may be considered alongside other treatment options. Safety considerations regarding mTOR inhibitor therapy are also reviewed. With evidence of beneficial effects in neurological and non-neurological TSC manifestations, mTOR inhibitors may represent a systemic treatment for TSC.

The economic burden of tuberous sclerosis complex in UK patients with renal manifestations: a retrospective cohort study in the clinical practice research datalink (CPRD)

BACKGROUND

Tuberous sclerosis complex (TSC) is a multi-system genetic disorder in which renal manifestations occur in ∼50% of children and 80% of adults. Since these often present alongside other manifestations, renal TSC is likely to incur significant costs. This study aims to quantify healthcare resource use (HCRU) and costs for renal TSC patients in the UK.

METHODS

TSC patients in the Clinical Practice Research Datalink (CPRD) linked to Hospital Episodes Statistics were identified from January 1987-June 2013. Clinical data were extracted over the entire history and costs were reported over the most recent 3-year period. HCRU was compared with a matched comparator cohort. Incremental costs were reported and the key cost drivers by primary manifestation category were identified by regression modeling.

RESULTS

A total of 79 renal TSC patients were identified with manifestations including chronic kidney disease stage 3-5 (with prevalence increasing with age) and renal angiomyolipoma. Renal TSC patients consistently reported greater HCRU than the comparator. Inpatient hospitalizations were more frequent for renal TSC patients (3.2 vs 1.6), but length of stay was comparable; however, 70.9% of renal TSC patients recorded no kidney-related procedures ever and averaged <1 test per year in the 3-year period. Average costs for renal TSC patients were nearly 3-fold greater than the comparator (£15,162 vs £5672). Costs increased with additional manifestation categories (£3600: only renal; £27,531: renal with ≥4 additional manifestation categories [25% of patients]). Additional nervous system and dermatology/psychiatric manifestations significantly (p < 0.028) affected costs.

CONCLUSIONS

Renal TSC patients have greater HCRU than the general CPRD population, likely to result from progression of renal disease and additional manifestations; however, surveillance for disease progression appears to be deficient. Inadequate monitoring may contribute to a lack of co-ordinated care and increased healthcare-associated costs. Efforts should be made to follow the TSC guidelines to effectively monitor and treat patients.

New developments in the genetics and pathogenesis of tumours in tuberous sclerosis complex

In just the past 5 years, dramatic changes have occurred in the clinical management of tuberous sclerosis complex (TSC). Detailed knowledge about the role of the TSC proteins in regulating the activity of the mammalian target of rapamycin complex 1 (mTORC1) underlies this paradigm-shifting progress. Advances continue to be made in understanding the genetic pathogenesis of the different tumours that occur in TSC, including pivotal discoveries using next-generation sequencing (NGS). For example, the pathogenesis of angiofibromas is now known to involve UV-induced mutations, and the pathogenesis of multifocal renal cell carcinoma (RCC) in TSC is now known to result from distinct second-hit mutations. In parallel, the pathological features of TSC-associated tumours, including TSC-associated renal cell carcinoma, continue to be defined, despite the fact that TSC was first described 180 years ago. Here, we review recent discoveries related to the pathological features and genetic pathogenesis of TSC-associated tumours. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The impact of renal angiomyolipoma on estimated glomerular filtration rate in patients with tuberous sclerosis complex

BACKGROUND

There is a growing concern that renal impairment may develop in patients with renal angiomyolipomas (AMLs) associated with tuberous sclerosis complex (TSC) as a consequence of the disease itself and/or the interventions to mitigate the risk of hemorrhage.

OBJECTIVE

To assess the estimated glomerular filtration rate (eGFR) in patients with bilateral renal AMLs and the impact of tumor burden and intervention on renal function.

DESIGN

Retrospective study.

SETTING

Urology department of a tertiary care hospital.

PATIENTS AND METHODS

All adult patients (>=18 years of age) with TSC-associated renal AMLs seen from October 1998 to June 2015. We included only patients with bilateral tumors or solitary kidneys at the last follow-up.

MAIN OUTCOME MEASURES

The eGFR, renal volume, and number and type of interventions.

RESULTS

We identified 12 patients (median age 27.6, interquartile range 23.7-39.9 years), a median follow-up period of 1266 days (33-3133), and a median renal size of 454.7 mL (interquartile range 344.7-1016.9 on the right side; 558.1 mL, interquartile range 253.7-1001.4 on the left). In 11 (91.7%) patients, the eGFR was > 60 mL/min/1.77 m2. Six patients had three total nephrectomies, one had a contralateral partial nephrectomy, and seven had selective arterial embolizations. Intervention was associated with a significantly reduced eGFR. The renal size did not correlate with the eGFR.

CONCLUSIONS

TSC-associated renal AMLs may attain a large size but normal renal function is maintained in 92% of patients. Interventions to mitigate the risk of hemorrhage are associated with decreased renal function.

LIMITATIONS

The renal size was used as a surrogate for tumor size. Other limitations were the limited number of patients and lack of split renal function testing.

Malignant presentation of uterine lymphangioleiomyomatosis

OBJECTIVE

The main aim of this case report was to present the method of diagnosis, management, and the 12-year-follow-up of a patient diagnosed with primary uterine lymphangioleiomyomatosis (LAM).

CASE REPORT

A 47-year-old woman was admitted to the Department of Thoracosurgery due to pulmonary lesions suspected to be metastatic. The potential primary site of the neoplasm was not identified by previous imaging studies and specialist counseling. The patient had a history of total abdominal hysterectomy without ovaries due to a uterine tumor recognized as cellular leiomyoma and left salpingo-oophorectomy due to a solid ovarian tumor also recognized as leiomyoma. She had previously undergone the removal of a left kidney angiomyolipoma. After histopathological examination of the pulmonary lesions and repeated evaluation of the ovarian and uterine tumors, the diagnosis of primary uterine LAM with metastases to the ovary and the lungs was established. Although new metastatic lesions occurred, the patient remained in good condition during the 12-year-follow-up.

CONCLUSION

The history of our patient and review of the literature suggest that although uterine LAM presents malignant features (i.e., metastasis), the disease is long lasting and the patient can be in good condition for a number of years.

Tuberous sclerosis complex: Imaging characteristics in 11 cases and review of the literature

Tuberous sclerosis complex (TSC) is an uncommon multiorgan disorder that may present many and different manifestations on imaging. Radiology plays an important role in diagnosis and management, and can substantially improve the clinical outcome of TSC. Therefore, a comprehensive understanding of this disease is essential for the radiologist. The manifestations of TSC on computer tomography (CT) and magnetic resonance (MR) images were analyzed. Eleven patients with a clinical diagnosis of TSC were retrospectively reviewed. Central nervous system lesions included subependymal nodules (SENs) (11/11), subependymal giant cell astrocytomas (SEGAs) (2/11), cortical and subcortical tuber lesions (5/11), and white matter lesions (4/11). Of the 6 patients with abdominal scans, there were 6 cases of renal angiomyolipomas (AMLs), and one case of hepatic AMLs. Of the 4 patients undergoing chest CT, lung lymhangioleiomyomatosis (LAM) (2/4), and multiple small sclerotic bone lesions (2/4) were observed. Different modalities show different sensitivity to the lesion. Analysis of images should be integrated with patients' history in order to diagnose TSC.

Acute renal failure unmasking Lesch-Nyhan disease in a patient with tuberous sclerosis complex

CASE REPORT

We report on a male patient with Tuberous Sclerosis Complex (TSC), which was prenatally diagnosed. At the age of 3 months the patient developed acute renal failure with excessive hyperuricemia. Kidney function improved after rehydration and application of rasburicase, however without full recovery. Due to the inappropriate high levels of uric acid compared to kidney function, screening of hypoxanthine-guanine phosphoribosyltransferase (HPRT) related diseases was initiated. Mutation analysis revealed a deletion of exon 2 and 3 of the HPRT gene confirming the diagnosis of Lesch-Nyhan Disease (LND). After initiation of allopurinol therapy renal function further improved. In the following months the patient developed clinically a typical neurological phenotype of LND and TSC with seizures, severe dystonia and developmental delay.

CONCLUSION

Acute renal failure is a rare complication of HPRT related diseases. Combination of two inherited diseases may lead to a delayed diagnosis due to a mixed and maybe misleading phenotype.

Tuberous sclerosis complex-associated renal angiomyolipomas: A single center study of 17 consecutive cases

The aim of the present study was to investigate the treatment options for patients with tuberous sclerosis complex (TSC)-associated renal angiomyolipomas (AMLs). A total of 17 patients who were consecutively diagnosed with TSC-associated renal AMLs at the Department of Urology of Zhongshan Hospital between 1998 and 2012 were included in the study. The patient cohort included 7 males and 10 females with a mean age of 37.6 years (range, 18-62 years). A total of 12 patients were diagnosed with renal AML with TSC during physical examination (PE), while 5 patients were admitted to the Emergency Department of Zhongshan Hospital due to spontaneous rupture of renal AMLs. All renal lesions were examined by ultrasonography and abdominal computed tomography prior to treatment. The primary outcome measure was the kidney reservation rate (patients that had not received nephrectomies) in the rupture group and PE group. Both abdominal ultrasonography and CT revealed AMLs in all patients and the mean tumor size was 10.0±4.0 cm (range, 3.0-17.5 cm). Overall, 9 patients underwent surgery, which included unilateral nephrectomy in 4 patients and unilateral partial nephrectomy/tumor enucleation in 5 patients. The remaining 8 patients received medical treatment. All patients were followed-up for between 10 and 67 months. One patient succumbed as a result of multiple organ failure, which was caused by hypovolemic shock due to the spontaneous rupture of renal AML. The kidney reservation rate during surgery was 87.5% (7/8) in the PE group and 25% (1/4) in the spontaneous rupture group. The management of TSC-associated renal AMLs differs from that of solitary sporadic AMLs. Surgical therapy is recommended following careful risk-benefit analysis.

Tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems and is caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. The disorder can affect both adults and children. First described in depth by Bourneville in 1880, it is now estimated that nearly 2 million people are affected by the disease worldwide. The clinical features of TSC are distinctive and can vary widely between individuals, even within one family. Major features of the disease include tumours of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. TSC1 (also known as hamartin) and TSC2 (also known as tuberin) form the TSC protein complex that acts as an inhibitor of the mechanistic target of rapamycin (mTOR) signalling pathway, which in turn plays a pivotal part in regulating cell growth, proliferation, autophagy and protein and lipid synthesis. Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment. In this Primer, we review the state-of-the-art knowledge in the TSC field, including the molecular and cellular basis of the disease, medical management, major knowledge gaps and ongoing research towards a cure.

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.

Inpp5e suppresses polycystic kidney disease via inhibition of PI3K/Akt-dependent mTORC1 signaling

Polycystic kidney disease (PKD) is a common cause of renal failure with few effective treatments. INPP5E is an inositol polyphosphate 5-phosphatase that dephosphorylates phosphoinositide 3-kinase (PI3K)-generated PI(3,4,5)P₃ and is mutated in ciliopathy syndromes. Germline Inpp5e deletion is embryonically lethal, attributed to cilia stability defects, and is associated with polycystic kidneys. However, the molecular mechanisms responsible for PKD development upon Inpp5e loss remain unknown. Here, we show conditional inactivation of Inpp5e in mouse kidney epithelium results in severe PKD and renal failure, associated with a partial reduction in cilia number and hyperactivation of PI3K/Akt and downstream mammalian target of rapamycin complex 1 (mTORC1) signaling. Treatment with an mTORC1 inhibitor improved kidney morphology and function, but did not affect cilia number or length. Therefore, we identify Inpp5e as an essential inhibitor of the PI3K/Akt/mTORC1 signaling axis in renal epithelial cells, and demonstrate a critical role for Inpp5e-dependent mTORC1 regulation in PKD suppression.

Pharmacokinetics and pharmacodynamics of everolimus in patients with renal angiomyolipoma and tuberous sclerosis complex or lymphangioleiomyomatosis

AIMS

The purpose was to determine the exposure-response relationship of everolimus in patients with angiomyolipoma from the EXIST-2 trial and to analyze the correlation between exposure and plasma concentrations of angiogenic biomarkers in these patients.

METHODS

One hundred and eighteen patients with angiomyolipoma associated with tuberous sclerosis complex (TSC) or sporadic lymphangioleiomyomatosis (sLAM) were randomly assigned 2 : 1 to receive everolimus 10 mg (n = 79) or placebo (n = 39) once daily. Blood samples for determining everolimus concentration were collected at weeks 2, 4, 12, 24 and 48 during double-blind treatment. Plasma samples for biomarker analysis were collected at baseline and weeks 4, 12, 24, 36, 48 and at the end of treatment. Concentrations of eight angiogenic biomarkers associated with tumour growth were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Peak and trough concentrations of everolimus in blood remained stable over time and similar to those reported in other indications. Substantial pharmacodynamic effects were observed in the everolimus, but not placebo, arm for three biomarkers: After 24 weeks of treatment, reduction of vascular endothelial growth factor D (VEGF-D) and collagen type IV (COL-IV) (mean fold-changes with 95% confidence intervals [CI] were 0.36 [0.33, 0.40], and 0.54 [0.51, 0.57], respectively, P < 0.001 for both), along with increased VEGF-A (mean fold-change of 1.59 [1.39, 1.80], P < 0.001), were seen. Furthermore, baseline VEGF-D and COL-IV levels were associated with angiomyolipoma size at baseline and with angiomyolipoma response to everolimus.

CONCLUSIONS

These findings suggest that plasma angiogenic markers may provide an objective measure of patient response to everolimus.

The clinical profile of tuberous sclerosis complex (TSC) in the United Kingdom: A retrospective cohort study in the Clinical Practice Research Datalink (CPRD)

BACKGROUND

Tuberous Sclerosis Complex (TSC) is a multi-system genetic disorder characterised by the development of benign growths and diverse clinical manifestations, varying in severity, age at onset and with high clinical burden.

AIMS

This longitudinal study aims to describe the broad spectrum of clinical manifestation profiles in a large, representative cohort of TSC patients in the UK in order to better understand disease complexity.

METHODS

TSC patients in the Clinical Practice Research Datalink (CPRD) and linked Hospital Episodes Statistics (CPRD-HES) were retrospectively identified between 1987 and 2013. Available history was extracted for each patient and clinical diagnosis, procedure and medication records reviewed. A random selection of patients from the CPRD-HES was used as a Comparator cohort.

RESULTS

Three hundred and thirty-four TSC patients with a mean (SD) age of 30.3 (18.6) years were identified (53% female). TSC was diagnosed at mean age 3.2 (4.2) years. Epilepsy and psychiatric manifestations were reported frequently in paediatric (77% and 55%, respectively) and adult patients (66% and 68%, respectively). The prevalence of manifestations in the TSC cohort was markedly higher versus the Comparator cohort. The majority of paediatric (46%) and adult TSC patients (62%) developed clinical manifestations affecting at least three organ systems and forty-nine distinctive organ system manifestation profiles were identified.

CONCLUSIONS

TSC patients present with multiple and complex clinical manifestations and profiles that necessitate the co-ordinated action of a multidisciplinary team in order to improve the quality and efficiency of care.

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.

Mammalian Target of Rapamycin Inhibitors and Life-Threatening Conditions in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a multisystem disease associated with an overall reduction in life expectancy due to the possible occurrence of different life-threatening conditions. Subjects affected by TSC are, in fact, at risk of hydrocephalus secondary to the growth of subependymal giant cell astrocytomas, or of sudden unexpected death in epilepsy. Other nonneurological life-threatening conditions include abdominal bleeding owing to renal angiomyolipomas rupture, renal insufficiency due to progressive parenchymal destruction by multiple cysts, pulmonary complications due to lymphangioleiomyomatosis, and cardiac failure or arrhythmias secondary to rhabdomyomas. In the last decades, there has been a great progress in understanding the pathophysiology of TSC-related manifestations, which are mainly linked to the hyperactivation of the so-called mammalian target of rapamycin (mTOR) pathway, as a consequence of the mutation in 1 of the 2 genes TSC1 or TSC2. This led to the development of new treatment strategies for this disease. In fact, it is now available as a biologically targeted therapy with everolimus, a selective mTOR inhibitor, which has been licensed in Europe and USA for the treatment of subependymal giant cell astrocytomas and angiomyolipomas in subjects with TSC. This drug also proved to benefit other TSC-related manifestations, including pulmonary lymphangioleiomyomatosis, cardiac rhabdomyomas, and presumably epileptic seizures. mTOR inhibitors are thus proving to be a systemic therapy able to simultaneously address different and potentially life-threatening complications, giving the hope of improving life expectation in individuals with TSC.

Genotype/Phenotype Correlations in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the development of widespread hamartomatous lesions in various organs, including brain, skin, kidneys, heart, and eyes. Central nervous system is almost invariably involved, with up to 85% of patients presenting with epilepsy, and at least half of patients having intellectual disability or other neuropsychiatric disorders including autism spectrum disorder. TSC is caused by the mutation in one of the 2 genes TSC1, at 9q34, and TSC2, at 16p13.3. They respectively encode for hamartin and tuberin, which form an intracellular complex inhibiting the mammalian target of rapamycin. Mammalian target of rapamycin overactivation following the genetic defect determines the cell growth and proliferation responsible for TSC-related lesions, as well as the alterations in neuronal excitability and synaptogenesis leading to epilepsy and neuropsychiatric disorders. A causative mutation for the disorder is identified in about 85% of patients with a clinical diagnosis of TSC. Mosaicism and technology limits likely explain most of the no mutation identified cases. This review confirms that patients with TSC2 mutations considered as a group usually present a more severe phenotype, characterized by higher number of tubers, earlier age at seizure onset and higher prevalence of intellectual disability. However, the clinical phenotype of the disease presents a high variability, thus making the prediction of the phenotype on an individual basis still challenging. The increasing application of new molecular techniques to subjects with TSC has the potential to significantly reduce the rate of patients with no mutation demonstrated and to identify an increasing higher number of mutations. This would hopefully allow a better characterization of higher risk mutations, which might help clinicians to plan individualized surveillance plans. Furthermore, the increasing availability of disease registries to collect clinical and genetics data of patients help to define more valid and clinically oriented genotype or phenotype correlations.

Multiple cystic lung disease

Multiple cystic lung disease represents a diverse group of uncommon disorders that can present a diagnostic challenge due to the increasing number of diseases associated with this presentation. High-resolution computed tomography of the chest helps to define the morphological aspects and distribution of lung cysts, as well as associated findings. The combination of appearance upon imaging and clinical features, together with extrapulmonary manifestations, when present, permits confident and accurate diagnosis of the majority of these diseases without recourse to open-lung biopsy. The main diseases in this group that are discussed in this review are lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis and folliculin gene-associated syndrome (Birt–Hogg–Dubé); other rare causes of cystic lung disease, including cystic metastasis of sarcoma, are also discussed. Disease progression is unpredictable, and understanding of the complications of cystic lung disease and their appearance during evolution of the disease are essential for management. Correlation of disease evolution and clinical context with chest imaging findings provides important clues for defining the underlying nature of cystic lung disease, and guides diagnostic evaluation and management.

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.

Tuberous sclerosis complex: the past and the future

Renal lesions represent the second most significant cause of morbidity and mortality in patients with tuberous sclerosis complex (TSC). Recent advances in the understanding of the pathophysiology of TSC have led to the exploration of new potential therapeutic targets. Clinical trials with mammalian target of rapamycin (mTOR) inhibitors have demonstrated promising results for several indications, such as renal angiomyolipoma, subependymal giant cell astrocytoma, lymphangioleiomyomatosis and facial angiofibromas. Currently, there is a scarcity of natural history data and randomized, placebo-controlled clinical trials on TSC. Recently, however, recommendations for the diagnostic criteria, surveillance, and management of TSC patients have been updated. This review focuses on these novel recommendations and highlights the need for multidisciplinary follow-up of this multi-systemic disease.

Neurological and neuropsychiatric aspects of tuberous sclerosis complex

Tuberous sclerosis (also known as tuberous sclerosis complex [TSC]) is a multisystem genetic disorder that affects almost every organ in the body. Mutations in the TSC1 or TSC2 genes lead to disruption of the TSC1-TSC2 intracellular protein complex, causing overactivation of the mammalian target of rapamycin (mTOR) protein complex. The surveillance and management guidelines and clinical criteria for tuberous sclerosis were revised in 2012, and mTOR inhibitors are now recommended as treatment options for subependymal giant cell astrocytomas and renal angiomyolipomas-two common features of the disease. However, most morbidity and mortality caused by tuberous sclerosis is associated with neurological and neuropsychiatric manifestations. Treatment of epilepsy associated with tuberous sclerosis remains a major challenge, with more than 60% of patients having ongoing seizures. Tuberous-sclerosis-associated neuropsychiatric disorders (TAND) are multilevel and occur in most individuals with the disorder, but are rarely assessed and treated. Clinical trials of mTOR inhibitors to treat seizures and TAND are underway. Management of the neurological and neuropsychiatric manifestations of the disorder should be coordinated with treatment of other organ systems. In view of the age-related expression of manifestations from infancy to adulthood, continuity of clinical care and ongoing monitoring is paramount, and particular attention is needed to plan transition of patient care from childhood to adult services.

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.

Long-Term Everolimus Treatment in Individuals With Tuberous Sclerosis Complex: A Review of the Current Literature

BACKGROUND

Tuberous sclerosis complex is a genetic disease usually caused by mutations to either TSC1 or TSC2, where its gene products are involved in the inhibition of the mammalian target of rapamycin pathway. Under normal cellular conditions, mammalian target of rapamycin (mTOR) regulates cell growth and proliferation in response to signals from nutrients or growth factors, but loss of TSC1 or TSC2 leads to overactivation of mTOR and uncontrolled cellular proliferation. Everolimus is an mTOR inhibitor approved for use in a number of indications where mTOR overactivation is implicated, including tuberous sclerosis complex.

METHODS AND PATIENTS

We conducted a literature search of PubMed to identify published articles about the long-term efficacy and safety of everolimus in patients with tuberous sclerosis complex.

RESULTS

The short-term efficacy and safety of everolimus in patients with tuberous sclerosis complex has been demonstrated in placebo-controlled trials, and open-label extension studies are ongoing to monitor long-term effects, including safety. Examples of regrowth following discontinuation of mTOR inhibitors suggest that everolimus needs to be given indefinitely to maintain suppression of subependymal giant cell astrocytoma and other tuberous sclerosis complex-associated disease manifestations. No additional safety concerns have been reported to date with long-term administration of everolimus, but published long-term data (>1 year treatment) are currently limited to a small open-label trial and case reports for this relatively rare condition.

CONCLUSIONS

From the limited data available, long-term administration of everolimus appears feasible with few safety concerns beyond those associated with short-term use. Further investigation is needed to determine the long-term efficacy and safety of everolimus in patients with tuberous sclerosis complex.

Cystic kidney disease: a primer

Renal cystic diseases encompass a broad group of disorders with variable phenotypic expression. Cystic disorders can present during infancy, childhood, or adulthood. Often, but not always, they can be distinguished by the clinical features including age at presentation, renal imaging characteristics, including cyst distribution, and the presence/distribution of extrarenal manifestations. It is important to take the clinical context into consideration when assessing renal cystic disease in children and adults. For example, solitary kidney cysts may be completely benign when they develop during adulthood but may represent early polycystic kidney disease when observed during childhood. In this review, we have categorized renal cystic disease according to inherited single-gene disorders, for example, autosomal recessive polycystic kidney disease; syndromic disorders associated with kidney cysts, for example, tuberous sclerosis complex; and nongenetic forms of renal cystic disease, for example, simple kidney cysts. We present an overview of the clinical characteristics, genetics (when appropriate), and molecular pathogenesis and the diagnostic evaluation and management of each renal cystic disease. We also provide an algorithm that distinguishes kidney cysts based on their clinical features and may serve as a helpful diagnostic tool for practitioners. A review of Autosomal Dominant Polycystic Disease was excluded as this disorder was reviewed in this journal in March 2010, volume 17, issue 2.

Annual review of children with tuberous sclerosis

Tuberous sclerosis complex is a complex childhood disorder characterised by the formation of hamartomas in multiple organs. Annual review of this disease is recommended to monitor the development of complications. We aim to provide a concise, evidence-based framework to assist clinicians during this annual review. We focus on the following areas: (A) what questions need to be asked during annual review, (B) which areas need emphasis on examination, (C) when is an investigation required and (D) referral to tertiary specialists and other members of the multidisciplinary team. It should also be noted that there are ongoing debates regarding screening intervals in certain areas. These include the frequency, modality of screening and degree of intervention for astrocytomas and renal angiomyolipomas. This review seeks to summarise the product of the ongoing debates, and provide evidence-based suggestions in light of the uncertainty.

Tuberous sclerosis complex

Tuberous sclerosis complex is an autosomal-dominant, neurocutaneous, multisystem disorder characterized by cellular hyperplasia and tissue dysplasia. The genetic cause is mutations in the TSC1 gene, found on chromosome 9q34, and TSC2 gene, found on chromosome 16p13. The clinical phenotypes resulting from mutations in either of the 2 genes are variable in each individual. Herein, advances in the understanding of molecular mechanisms in tuberous sclerosis complex are reviewed, and current guidelines for diagnosis, treatment, follow-up, and management are summarized.

Tuberous Sclerosis Complex: new criteria for diagnostic work-up and management

Tuberous sclerosis complex (TSC) is a rare genetic multisystem disorder, characterized by predominantly benign tumors in potentially all organ systems. System involvement, severity of clinical symptoms and the response to treatment are age-dependent and heterogeneous. Consequently, the disorder is still not recognized in a considerable number of patients. The diagnostic criteria and the guidelines for surveillance and management of patients with TSC were revised, and the establishment of specialized TSC-centers was strongly recommended during an International Consensus Conference in 2012. TOSCA (TuberOus SClerosis registry to increase disease Awareness), an international patient registry, was started to allow new insights into the causes of different courses. Finally, there are-since the approval of the mTOR inhibitor Everolimus-promising new therapeutic approaches.This review focuses on the various TSC related symptoms occurring at different ages, the novel recommendations for diagnosis and treatment as well as the need for multidisciplinary follow-up.

Response to everolimus is seen in TSC-associated SEGAs and angiomyolipomas independent of mutation type and site in TSC1 and TSC2

Tuberous sclerosis complex is an autosomal dominant disorder that occurs owing to inactivating mutations in either TSC1 or TSC2. Tuberous sclerosis complex-related tumors in the brain, such as subependymal giant cell astrocytoma, and in the kidney, such as angiomyolipoma, can cause significant morbidity and mortality. Recently, randomized clinical trials (EXIST-1 and EXIST-2) of everolimus for each of these tuberous sclerosis complex-associated tumors demonstrated the benefit of this drug, which blocks activated mammalian target of rapamycin complex 1. Here we report on the spectrum of mutations seen in patients treated during these trials and the association between mutation and response. TSC2 mutations were predominant among patients in both trials and were present in nearly all subjects with angiomyolipoma in whom a mutation was identified (97%), whereas TSC1 mutations were rare in those subjects (3%). The spectrum of mutations seen in each gene was similar to those previously reported. In both trials, there was no apparent association between mutation type or location within each gene and response to everolimus. Everolimus responses were also seen at a similar frequency for the 16–18% of patients in each trial in whom no mutation in either gene was identified. These observations confirm the strong association between TSC2 mutation and angiomyolipoma burden seen in previous studies, and they indicate that everolimus response occurs regardless of mutation type or location or when no mutation in TSC1 or TSC2 has been identified.

Selected case from the Arkadi M. Rywlin International Pathology Slide Series: Asymmetric, segmental glomerulocystic kidney in an infant with tuberous sclerosis complex

A Hispanic newborn male, the product of nonconsanguineous parents, exhibited major and minor signs of tuberous sclerosis complex (TSC). MRI of the abdomen disclosed a discrete unilateral, cystic, right upper pole renal mass that prompted a nephrectomy. Histologic examination showed a polycystic renal mass that involved all segments of the nephron, with a preponderantly glomerulocystic pattern. The cysts were rounded, uniform, and small, most measuring 2 to 3 mm in diameter. The lining of the cysts was hyperplastic, made up of tall epithelial cells with eosinophilic granular cytoplasm and large nuclei, and focally formed mounds and papillary tufts. DNA analysis detected a constitutional deletion of exon 1 in the TSC2 gene on chromosome 16p13.3. Cystogenesis in TSC2 is manifested because of alteration or dysfunction of the primary cilium, where polycystin, the gene product of PKD1 gene, is localized. Renal cysts are often seen in TSC, varying in number from a few to innumerable, involving all segments of the nephron, including Bowman spaces, and are currently considered as one of the minor diagnostic features. A glomerulocystic pattern is a rare form of kidney involvement in TSC that aptly describes the innumerable cystically dilated Bowman spaces. Glomerulocystic kidney associated with the aforementioned hyperplastic epithelial lining (TSC epithelium) is sufficiently characteristic that could conceivably serve as a major TSC feature in the future.

A shower of second hit events as the cause of multifocal renal cell carcinoma in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a genetic disorder characterized by seizures and tumor formation in multiple organs, mainly in the brain, skin, kidney, lung and heart. Renal cell carcinoma (RCC) occurs in ∼3% of TSC patients, and typically develops at age <50. Here we describe genetic findings in two TSC patients with multiple renal tumors, each of whom had the germline mutation TSC2 p.R905Q. The first (female) TSC patient had a left followed by a right nephrectomy at ages 24 and 27. Both kidneys showed multifocal TSC-associated papillary RCC (PRCC). Targeted, next-generation sequencing (NGS) analysis of TSC2 in five tumors (four from the left kidney, one from the right) showed loss of heterozygosity in one tumor, and four different TSC2 point mutations (p.E1351*, p.R1032*, p.R1713H, c.4178_4179delCT) in the other four samples. Only one of the 11 other tumors available from this patient had one of the TSC2 second hit mutations identified. Whole-exome analysis of the five tumors identified a very small number of additional mutated genes, with an average of 3.4 nonsilent coding, somatic mutations per tumor, none of which were seen in >1 tumor. The second (male) TSC patient had bilateral partial nephrectomies (both at age 36), with similar findings of multifocal PRCC. NGS analysis of TSC2 in two of these tumors identified a second hit mutation c.2355+1G>T in one sample that was not seen in other tumors. In conclusion, we report the first detailed genetic analysis of RCCs in TSC patients. Molecular studies indicate that tumors developed independently due to various second hit events, suggesting that these patients experienced a 'shower' of second hit mutations in TSC2 during kidney development leading to this severe phenotype.

Malignant perivascular epithelioid cell tumor of the gallbladder: a case report and review of literature

Perivascular epithelioid cell tumors are rare mesenchymal neoplasms composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. The perivascular epithelioid cell tumor family includes angiomyolipoma, clear cell sugar tumor of the lung, lymphangioleiomyomatosis, clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres, and rare clear cell tumors of other anatomic sites. Perivascular epithelioid cell tumors have been reported previously in various sites, but to our knowledge not in the gallbladder. We report here, for the first time, a malignant perivascular epithelioid cell tumor arising in the gallbladder.

Epithelioid Angiomyolipoma in a Pediatric Patient: Case Report and Review of Literature

We report a case of a 17-year-old girl with tuberous sclerosis complex who underwent partial nephrectomy for a newly discovered 7.5-cm renal mass subsequently determined to be an epithelioid angiomyolipoma, a rare variant of angiomyolipoma that can be confused clinically, radiographically, and pathologically for renal cell carcinoma. Proper diagnosis and treatment are critical, especially in the pediatric patient. This case report and review of literature serve at increasing the awareness of this renal tumor, with its somewhat unpredictable outcome, reviewing the pertinent literature on the topic of epithelioid angiomyolipoma in the clinical setting of tuberous sclerosis complex.

Evidence for pericyte origin of TSC-associated renal angiomyolipomas and implications for angiotensin receptor inhibition therapy

Nearly all patients with tuberous sclerosis complex (TSC) develop renal angiomyolipomas, although the tumor cell of origin is unknown. We observed decreased renal angiomyolipoma development in patients with TSC2- polycystic kidney disease 1 deletion syndrome and hypertension that were treated from an early age with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers compared with patients who did not receive this therapy. TSC-associated renal angiomyolipomas expressed ANG II type 1 receptors, platelet-derived growth factor receptor-β, desmin, α-smooth muscle actin, and VEGF receptor 2 but did not express the adipocyte marker S100 or the endothelial marker CD31. Sera of TSC patients exhibited increased vascular mural cell-secreted peptides, such as VEGF-A, VEGF-D, soluble VEGF receptor 2, and collagen type IV. These findings suggest that angiomyolipomas may arise from renal pericytes. ANG II treatment of angiomyolipoma cells in vitro resulted in an exaggerated intracellular Ca(2+) response and increased proliferation, which were blocked by the ANG II type 2 receptor antagonist valsartan. Blockade of ANG II signaling may have preventative therapeutic potential for angiomyolipomas.

The ominous sequence in patients with tuberous sclerosis complex

BACKGROUND

The clinical phenotypes and their severity in patients with tuberous sclerosis complex can be quite variable and are sometimes never determined simply by the primary mutation. These make clinically selecting appropriate treatments and predicting disease outcome difficult. In this report, the prognostic ominous sequence was evaluated in association with clinical manifestations and gene mutations.

METHODS

The patients were classified by each renal lesion of angiomyolipomas and polycystic disease. The other clinical manifestations and outcomes of epilepsy, mental retardation, facial angiofibromas, subependymal giant cell astrocytoma, cortical tubers were reviewed and each gene mutations were analyzed in seven unrelated patients.

RESULTS

Two patients with multiple and large proliferative renal angiomyolipoma showed poor clinical outcome than the patients with other renal lesions. These patients presented with progressively proliferative facial angiofibroma, West syndrome, Lennox-Gastaut syndrome, severe mental retardation, subependymal giant cell astrocytoma and they were affected by TSC2 gene mutations.

CONCLUSION

The sequence of progressively proliferative renal angiomyolipoma, facial angiofibroma, West syndrome and TSC2 gene mutations might be prognostic ominous factors.

Hereditary kidney cancer syndromes

Inherited susceptibility to kidney cancer is a fascinating and complex topic. Our knowledge about types of genetic syndromes associated with an increased risk of disease is continually expanding. Currently, there are 10 syndromes associated with an increased risk of all types of kidney cancer, which are reviewed herein. Clear cell kidney cancer is associated with von Hippel Lindau disease, chromosome 3 translocations, PTEN hamartomatous syndrome, and mutations in the BAP1 gene as well as several of the genes encoding the proteins comprising the succinate dehydrogenase complex (SDHB/C/D). Type 1 papillary kidney cancers arise in conjunction with germline mutations in MET and type 2 as part of hereditary leiomyomatosis and kidney cell cancer (fumarate hydratase [FH] mutations). Chromophone and oncocytic kidney cancers are predominantly associated with Birt-Hogg-Dubé syndrome. Patients with Tuberous Sclerosis Complex (TSC) commonly have angiomyolipomas and rarely their malignant counterpart epithelioid angiomyolipomas. The targeted therapeutic options for the kidney cancer associated with these diseases are just starting to expand and are an area of active clinical research.

Everolimus in the treatment of subependymal giant cell astrocytomas, angiomyolipomas, and pulmonary and skin lesions associated with tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by inactivating mutations in either the TSC1 or TSC2 genes. It is characterized by the development of multiple, benign tumors in several organs throughout the body. Lesions occur in the brain, kidneys, heart, liver, lungs, and skin and result in seizures and epilepsy, mental retardation, autism, and renal and pulmonary organ system dysfunction, as well as other complications. Elucidation of the molecular pathways and etiological factors responsible for causing TSC has led to a paradigm shift in the management and treatment of the disease. TSC1 or TSC2 mutations lead to constitutive upregulation of the mammalian target of rapamycin pathway, which affects many cellular processes involved in tumor growth. By targeting mammalian target of rapamycin with everolimus, an orally active rapamycin derivative, clinically meaningful and statistically significant reductions in tumor burden have been achieved for the main brain (subependymal giant cell astrocytoma) and renal manifestations (angiomyolipoma) associated with TSC. This review provides an overview of TSC, everolimus, and the clinical trials that led to its approval for the treatment of TSC-associated subependymal giant cell astrocytoma and renal angiomyolipoma.

Bilateral renal cell carcinoma in a paediatric patient with tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a genetic neurocutaneous disorder characterised by seizures, mental retardation and hamartoma formation in multiple organs, mainly in the brain, skin, kidney, liver, lung and heart. Renal manifestations occur in about 60-80% of all patients with TSC and their rate increases with age. We report the case of a 17-year-old boy with tuberous sclerosis who presented with abdominal pain associated with kidney failure. Investigation revealed bilateral renal lesions, suggesting angiomyolipomas. On further work-up, malignancy was suspected and the patient underwent bilateral partial nephrectomy with histological diagnosis of bilateral renal cell carcinoma. This is a rare complication of TSC, particularly in a paediatric setting. Adequate surveillance of kidney disorders in patients with TSC is warranted, to guarantee an early diagnosis and treatment.