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

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.

Single-Center Experience of Pediatric Cystic Kidney Disease and Literature Review

INTRODUCTION

Pediatric cystic kidney disease (CyKD) includes conditions characterized by renal cysts. Despite extensive research in this field, there are no reliable genetics or other biomarkers to estimate the phenotypic consequences. Therefore, CyKD in children heavily relies on clinical and diagnostic testing to predict the long-term outcomes.

AIM

A retrospective study aimed to provide a concise overview of this condition and analyze real-life data from a single-center pediatric CyKD cohort followed during a 12-year period.

METHODS AND MATERIALS

Medical records were reviewed for extensive clinical, laboratory, and radiological data, treatment approaches, and long-term outcomes.

RESULTS

During the study period, 112 patients received a diagnosis of pediatric CyKD. Male patients were more involved than female (1:0.93). Fifty-six patients had a multicystic dysplastic kidney; twenty-one of them had an autosomal dominant disorder; fifteen had an isolated renal cyst; ten had been diagnosed with autosomal recessive polycystic kidney disease; three had the tuberous sclerosis complex; two patients each had Bardet-Biedl, Joubert syndrome, and nephronophthisis; and one had been diagnosed with the trisomy 13 condition. Genetic testing was performed in 17.9% of the patients, revealing disease-causing mutations in three-quarters (75.0%) of the tested patients. The most commonly presenting symptoms were abdominal distension (21.4%), abdominal pain (15.2%), and oligohydramnios (12.5%). Recurrent urinary tract infections (UTI) were documented in one-quarter of the patients, while 20.5% of them developed hypertension during the long-term follow-up. Antibiotic prophylaxis and antihypertensive treatment were the most employed therapeutic modalities. Seventeen patients progressed to chronic kidney disease (CKD), with thirteen of them eventually reaching end-stage renal disease (ESRD). The time from the initial detection of cysts on an ultrasound (US) to the onset of CKD across the entire cohort was 59.0 (7.0-31124.0) months, whereas the duration from the detection of cysts on an US to the onset of ESRD across the whole cohort was 127.0 (33.0-141.0) months. The median follow-up duration in the cohort was 3.0 (1.0-7.0) years. The patients who progressed to ESRD had clinical symptoms at the time of initial clinical presentation.

CONCLUSION

This study is the first large cohort of patients reported from Croatia. The most common CyKD was the multicystic dysplastic kidney disease. The most common clinical presentation was abdominal distention, abdominal pain, and oliguria. The most common long-term complications were recurrent UTIs, hypertension, CKD, and ESRD.

Endovascular treatment of sporadic renal angiomyolipoma presenting with Wunderlich syndrome

Angiomyolipomas are benign renal hamartomas with - fat, smooth muscle, and abnormal blood vessel (tortuous, dysmorphic) components. The risk of hemorrhage is related to size of the tumor, presence of aneurysm, associations with tuberous sclerosis. In this case report we review the case of a 42-year-old woman presenting with acute flank pain and decreased hemoglobin, who was diagnosed with AML with right renal artery pseudo aneurysm on CT. Subsequent coil embolization of feeding vessels and using PVA particles was successfully done. Selective embolization remains a minimally invasive, attractive option, and a nephron sparing approach.

Long-term efficacy of selective arterial embolisation of renal angiomyolipoma

OBJECTIVE

To evaluate the long-term efficacy of selective arterial embolisation in renal angiomyolipoma (AML), with emphasis on tumour shrinkage, potential regrowth and the necessity of supplementary procedures.  Material and methods: A retrospective review of all 58 consecutive embolisations at two institutions, between 1999 and 2018, was performed. Clinical notes, laboratory data and imaging were reviewed.

RESULTS

The overall complication rate was 6.8%, with no Clavien-Dindo grades III-V complications. Kidney function was unaffected by embolisation as measured by creatinine. Median radiological follow-up was 4.8 years (interquartile range [IQR]: 2.8-7.8), and median clinical follow-up was 7.5 years (IQR: 4.7-14.0). Decreasing AML size was observed in 96% of procedures. Maximal shrinkage (30% median diameter decrease; IQR: 15-44) was reached after median 2.2 years (IQR: 0.6-4.8). During follow-up, regrowth occurred in 38% of patients, and four bleeding episodes occurred in three patients with tuberous sclerosis. Growing size and/or rebleeding prompted a redo embolisation in 9% of spontaneous AML and 50% of tuberous sclerosis-associated AML.

CONCLUSIONS

Being a well-tolerated treatment with few complications, selective arterial embolisation renders a pronounced size-reduction in most patients with AML, and kidney function is preserved. Regrowth is common, and a radiological follow-up is necessary. Tuberous sclerosis is a risk factor for the need of reintervention.

Childhood tuberous sclerosis complex in southern Sweden: a paradigm shift in diagnosis and treatment

AIM

To investigate the complete clinical spectrum of individuals with paediatric tuberous sclerosis complex in southern Sweden and explore changes over time.

METHODS

In this retrospective observational study, 52 individuals aged up to 18 years at the study start were followed-up at regional hospitals and centres for habilitation from 2000 to 2020.

RESULTS

Cardiac rhabdomyoma was detected prenatally/neonatally in 69.2% of the subjects born during the latest ten years of the study period. Epilepsy was diagnosed in 82.7% of subjects, and 10 (19%) were treated with everolimus, mainly (80%) for a neurological indication. Renal cysts were detected in 53%, angiomyolipomas in 47%, astrocytic hamartomas in 28% of the individuals. There was a paucity of standardized follow-up of cardiac, renal, and ophthalmological manifestations and no structured transition to adult care.

CONCLUSION

Our in-depth analysis shows a clear shift towards an earlier diagnosis of tuberous sclerosis complex in the latter part of the study period, where more than 60% of cases showed evidence of this condition already in utero due to the presence of a cardiac rhabdomyoma. This allows for preventive treatment of epilepsy with vigabatrin and early intervention with everolimus for potential mitigation of other symptoms of tuberous sclerosis complex.

Heterozygous germline FLCN mutation in Birt-Hogg-Dubé syndrome with bilateral renal hybrid oncocytic/chromophobe tumor and unilateral renal chromophobe cell carcinoma: a case report

BACKGROUND

Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant tumor syndrome caused by Folliculin (FLCN) gene mutation. The clinical manifestations are diverse, and the renal tumor is the most serious.

CASE PRESENTATION

We report the case of a 51-year-old female with multiple space-occupying lesions in both kidneys, as well as bilateral renal cysts and multiple lung cysts. The resected tumors were finally diagnosed as bilateral renal hybrid oncocytic/chromophobe tumor (HOCT) and unilateral chromophobe cell carcinoma. A history of pneumothorax surgery 4 years ago was convinced. All of these strongly suggested the possibility of BHD syndrome. Gene test confirmed a heterozygous germline FLCN nonsense mutation (c.1429C > T, p.Arg477Ter). The patient is still doing well after 20 months of follow-up (cut-off date July 2022).

CONCLUSION

This is a case of BHD syndrome presented with bilateral renal tumor, renal cysts, and multiple lung cysts, and confirmed by gene testing. Patients with any combination of one or more of the manifestations should remain alert to the BHD syndrome. Our report will help to deepen the understanding of the clinicopathological features and molecular changes of BHD syndrome.

Giant cyst-like cortical tubers in an adult with tuberous sclerosis presenting as spastic tetraplegia

Introduction and importance

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by inactivating mutations in TSC1 or TSC2 genes, resulting in benign lesions that involve multiple organs including the central nerves system.

Case presentation

A 39-year-old male of known TSC presented with inability to walk for two months. On physical examination, he was consciously oriented and cooperative, but he had spastic tetraparesis in the muscle-motor examination. On brain imaging, cystic lesions of various sizes in the supra and infratentorial regions were observed, consistent with giant cyst-like tubers. However, they could not differentiate from TSC related brain tumors based on the imaging findings. He underwent surgical intervention to resect/evacuate the large cystic lesion, which had the mass effects on the brain stem. The pathologic examinations revealed no malignant changes.

Clinical discussion

Although the cyst-like lesions in the cortex and white matter have been reported in several previous studies of TSC, they usually had a small size and similar intensity to CSF on T2- weighted MRI and low intensity on FLAIR images.

Conclusion

Giant cyst-like cortical tubers are exceedingly rare and atypical findings of tuberous sclerosis complex, which are usually associated with epilepsy and neurological deficits. Though many authors recommend the brain MRI as a screening tool for patients with TSC once every 1–3 years until the age of 25, our report showed that the brain lesions may develop in patients with TSC even after the age of 25. Thus, the MRI should be used periodically in all patients with TSC to timely detect the brain lesions and prevent the patient's disability. Surgical resection is the mainstay of treatment for the symptomatic cystic-like cortical tuber; however, it may recur after resection.

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Giant cyst-like cortical tubers are rare and atypical findings of tuberous sclerosis complex.

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They are usually associated with epilepsy and neurological deficits.

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MRI should be used periodically in all patients with tuberous sclerosis complex to timely detect the brain lesions.

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Surgical resection is the mainstay of treatment. However, these lesions may recur after resection.

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

Purpose:

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

Material and Methods:

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

Result:

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

Conclusions:

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

Utility of contrast-enhanced ultrasound for solid mass surveillance and characterization in children with tuberous sclerosis complex: an initial experience

BACKGROUND

Patients with tuberous sclerosis complex (TSC) can develop solid kidney masses from childhood. Imaging surveillance is done to detect renal cell carcinoma (RCC) and angiomyolipomas (AML), including AMLs at risk for hemorrhage. Intravenous contrast-enhanced ultrasound (CEUS) may be useful for screening as ultrasound is well tolerated by children and ultrasound contrast agents (UCA) are not nephrotoxic.

METHODS

Retrospective review of kidney CEUS exams of pediatric TSC patients. Qualitative CEUS analysis by consensus of 3 radiologists assessed rate, intensity, and pattern of lesion enhancement. Quantitative CEUS analysis was performed using Vuebox®. Where available, abdominal MRI was analyzed qualitatively for the same features and quantitatively by in-house-developed software. Time-intensity curves were generated from both CEUS and MRI where possible. Appearance of lesions were compared between CEUS and MRI and histology where available.

RESULTS

Nine masses in 5 patients included one histologically proven RCC and 8 AMLs diagnosed by imaging. Quantitative CEUS of RCC showed malignant features including increased peak enhancement 162%, rapid wash-in rate 162%, and elevated washout rate 156% compared to normal kidney tissue; versus AML which was 68%, 105%, and 125%, respectively. All masses were hypoenhancing on MRI compared to normal kidney tissue; MR dynamic contrast study offered no distinction between RCC and AML. The only MRI feature differentiating RCC from AML was absence of fat.

CONCLUSION

Temporal resolution afforded by CEUS was useful to distinguish malignant from benign kidney masses. CEUS may prove useful for screening, characterizing, and follow-up of kidney lesions in pediatric TSC patients.

Giant renal pseudoaneurysm complicating angiomyolipoma in a patient with tuberous sclerosis complex: An unusual case report and review of the literature

Introduction

Angiomyolipomas (AMLs) are uncommon benign lesions, which are composed of dysmorphic blood vessels, adipose tissue, and smooth muscle components. They tend to bleed because of the hypervascularity and the presence of small aneurysms, leading to life-threatening complications.

Presentation of case

A 31-year-old female was presented to the emergency service of our hospital, complaining of left flank pain for 1 week followed by hematuria for one day. Radiologic imaging showed the features of a giant renal pseudoaneurysm. Superselective embolization was applied and she had an uneventful recovery.

Discussion

The blood vessels in AML are tortuous and thick-walled with the absence of supportive elastic tissue, which tend to the formation of the intralesional pseudoaneurysm. The risk of bleeding is higher with tumors larger than 4 cm, rapid tumor growth, and aneurysms larger than 0.5 cm. Early detection and treatment are essential for the prevention of bleeding and improving patient outcomes.

Conclusion

Giant pseudoaneurysm in a renal angiomyolipoma associated with tuberous sclerosis complex is a rare entity, often leading to potentially life-threatening bleeding. Selective angioembolization is recommended as firstline therapy for bleeding AML and is increasingly used as a preventive treatment for AML at risk of bleeding. However, a high incidence of the recurrence requires caution and a close longtime follow-up. Surgical intervention is indicated if the hemorrhage is not responsive to embolization or if there is suspicion of malignancy.

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Renal pseudoaneurysm is a rare, but potentially life-threatening complication of tuberous sclerosis-related angiomyolipoma.

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Early detection is essential for the prevention of bleeding and improving the patient outcomes.

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Selective angioembolization is recommended as firstline therapy for bleeding angiomyolipoma.

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Surgical intervention is indicated if the hemorrhage is not responsive to embolization.

Natural growth pattern of sporadic renal angiomyolipoma

BACKGROUND

Surveillance of sporadic renal angiomyolipomas is a growing issue for physicians and radiologists. Current treatment recommendations favor active surveillance. However, the evidence underlying these is based on small case series, which also typically include angiomyolipomas associated with tuberous sclerosis.

PURPOSE

To evaluate the natural growth pattern of sporadic renal angiomyolipomas in patients without tuberous sclerosis.

MATERIAL AND METHODS

A retrospective review was performed in three separate tertiary referral centers. A keyword search of each institutions PACS history was performed. Inclusion criteria were angiomyolipomas > 1 cm in size, three years of follow-up, and lesions requiring treatment before reaching three years of follow-up. Exclusion criteria included a diagnosis of tuberous sclerosis, pregnancy, prior treatment with embolization without any prior imaging, and lesions which were treated on presentation. Growth of the angiomyolipomas was evaluated on the basis of maximum dimension on initial and follow-up images.

RESULTS

Sixty-three patients were identified in total, with 64 lesions eligible for inclusion. The majority of patients were women (55/63). The mean age at which the angiomyolipomas discovered was 56.4 years. Mean total growth was 0.085 mm and mean follow-up was 65.5 months. At initial measurement, the mean maximum dimension of the lesions in our cohort was 2.08 cm. After follow-up, this was 2.16 cm. The average rate of growth was 0.015 cm per year.

CONCLUSION

Sporadic angiomyolipomas exhibit minimal, if any, natural growth. Current surveillance strategies could be relaxed.

Performance of simultaneous multi-slice accelerated diffusion-weighted imaging for assessing focal renal lesions in pediatric patients with tuberous sclerosis complex

BACKGROUND

Diffusion-weighted imaging (DWI) is a useful MRI technique to characterize abdominal lesions in children, but long acquisition times can lead to image degradation. Simultaneous multi-slice accelerated DWI is a promising technique to shorten DWI scan times.

OBJECTIVE

To test the feasibility of simultaneous multi-slice DWI of the kidneys in pediatric patients with tuberous sclerosis complex (TSC) and to evaluate the accelerated protocol regarding image quality and quantitative apparent diffusion coefficient (ADC) values compared to standard echoplanar DWI sequence.

MATERIALS AND METHODS

We included 33 children and adolescents (12 female, 21 male; mean age 10±5 years) with TSC and renal cyst or angiomyolipoma on 3-tesla (T) MRI from 2017 to 2019. All studies included both free-breathing standard echoplanar DWI and simultaneous multi-slice DWI sequences. Subjective and quantitative image quality was evaluated using a predefined 5-point scale. ADC values were obtained for all renal cysts and angiomyolipomas ≥5 mm. All statistical analysis was performed using Stata/SE v15.1.

RESULTS

Simultaneous multi-slice DWI ADC values were slightly lower compared to standard echoplanar DWI for both renal cysts and angiomyolipomas (mean difference 0.05×10^-3 mm²/s, 95% confidence interval [CI] 0.40-0.50 and 0.024×10^-3 mm²/s, 95% CI 0.17-0.21, respectively, with P>0.1). Our results showed that renal lesions with ADC values >1.69×10^-3 mm²/s were all cysts, whereas lesions with values <1.16×10^-3 mm²/s were all angiomyolipomas. However, ADC values could not discriminate between lipid-rich and lipid-poor angiomyolipomas (P>0.1, for both sequences).

CONCLUSION

A 55% reduction in scan time was achieved using simultaneous multi-slice DWI for abdominal imaging in children with TSC, with near identical image quality as standard DWI. These results suggest that multi-slice techniques should be considered more broadly as an MRI acceleration technique in children.

Abdominal ultrasonographic manifestations in pediatric patients with tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare genetic disease which leads to formation of benign tumors in the brain and other organs of the body. Ultrasound (US) can detect the location, quantity, size and internal echo of TSC-associated renal diseases, liver angiomyolipoma (AML), and co-existing lesions, providing important diagnostic basis for clinical diagnosis. The aim of the present study was to investigate the abdominal ultrasonographic features of pediatric TSC and explore the advantages of abdominal ultrasonography in clinical practice.

METHODS

Data of children with TSC, who presented to the Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, between January 2016 and November 2018, were analyzed by a retrospective chart review. The cases were identified from electronic medical records (EMR) system and underwent ultrasonography, we yielded a total of 12 patients.

RESULTS

The 12 pediatric patients, including 5 boys and 7 girls, ranged in age from 9 months to 13 years old. And they all had a history of epilepsy. All the patients underwent brain magnetic resonance imaging (MRI) or computed tomography (CT) examination, which revealed a scattered distribution of multiple hyperintense nodules. Of the 12 patients, 10 had TSC-associated bilateral renal AMLs, 5 had hepatic AML, and 4 had renal cysts.

CONCLUSIONS

US is a useful and non-invasive tool for the detection of TSC-associated renal and liver lesions and for clinical follow-up among pediatric patients.

Renal Manifestations of Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a genetic condition caused by a mutation in either the TSC1 or TSC2 gene. Disruption of either of these genes leads to impaired production of hamartin or tuberin proteins, leading to the manifestation of skin lesions, tumors, and seizures. TSC can manifest in multiple organ systems with the cutaneous and renal systems being the most commonly affected. These manifestations can secondarily lead to the development of hypertension, chronic kidney disease, and neurocognitive declines. The renal pathologies most commonly seen in TSC are angiomyolipoma, renal cysts, and less commonly, oncocytomas. In this review, we highlight the current understanding on the renal manifestations of TSC along with current diagnosis and treatment guidelines.

Magnetic resonance imaging features of minimal-fat angiomyolipoma and causes of preoperative misdiagnosis

BACKGROUND

Minimal-fat angiomyolipoma (mf-AML) is often misdiagnosed as renal cell carcinoma before surgery.

AIM

To analyze the magnetic resonance imaging (MRI) features of mf-AML and the causes of misdiagnosis by MRI before operation.

METHODS

A retrospective analysis was performed on ten patients with mf-AML confirmed by surgical pathology, all of whom underwent preoperative MRI examination to analyze the morphological characteristics and MRI signals of the tumor.

RESULTS

MRI revealed a circular-like mass in 4/10 (40%) patients, an oval mass in 6/10 patients (60%), a mass with a capsule in 9/10 patients (90%), and a mass with a lipid component in 7/10 patients (70%). The diameter of the masses in all ten patients was from 11 to 47 mm; the diameter was between 11 mm and 40 mm in 8/10 (80%) patients and between 40 mm and 47 mm in 2/10 (20%) patients.

CONCLUSION

An oval morphological characteristic is strong evidence for the diagnosis of mf-AML, while a capsule and lipids are atypical manifestations of mf-AML.

Metformin effectively treats Tsc1 deletion-caused kidney pathology by upregulating AMPK phosphorylation

Tuberous sclerosis complex (TSC) is characterized by hamartomatous lesions in multiple organs, with most patients developing polycystic kidney disease and leading to a decline of renal function. TSC is caused by loss-of-function mutations in either Tsc1 or Tsc2 gene, but currently, there is no effective treatment for aberrant kidney growth in TSC patients. By generating a renal proximal tubule-specific Tsc1 gene-knockout (Tsc1 ptKO) mouse model, we observed that Tsc1 ptKO mice developed aberrantly enlarged kidneys primarily due to hypertrophy and proliferation of proximal tubule cells, along with some cystogenesis, interstitial inflammation, and fibrosis. Mechanistic studies revealed inhibition of AMP-activated protein kinase (AMPK) phosphorylation at Thr-172 and activation of Akt phosphorylation at Ser-473 and Thr-308. We therefore treated Tsc1 ptKO mice with the AMPK activator, metformin, by daily intraperitoneal injection. Our results indicated that metformin increased the AMPK phosphorylation, but decreased the Akt phosphorylation. These signaling modulations resulted in inhibition of proliferation and induction of apoptosis in the renal proximal tubule cells of Tsc1 ptKO mice. Importantly, metformin treatment effectively prevented aberrant kidney enlargement and cyst growth, inhibited inflammatory response, attenuated interstitial fibrosis, and protected renal function. The effects of metformin were further confirmed by in vitro experiments. In conclusion, this study indicates a potential therapeutic effect of metformin on Tsc1 deletion-induced kidney pathology, although currently metformin is primarily prescribed to treat patients with type 2 diabetes.

Fate of Pediatric Renal Angiomyolipoma During mTOR Inhibitor Treatment in Tuberous Sclerosis Complex

OBJECTIVE

To evaluate the clinical and radiographic follow-up of renal angiomyolipoma (AML) in pediatric patients with tuberous sclerosis complex (TSC) on mTOR inhibitors.

METHODS

We performed retrospective chart review of children who were diagnosed with TSC between 2000 and 2019 and prescribed everolimus at age ≤18 years. Treatment assessment was performed in patients who were medically-compliant by serum drug trough levels and who had at least a baseline and one subsequent renal imaging study.

RESULTS

Nineteen patients were analyzed. Average age of everolimus initiation was 9 years, and indication was neurologic in 17 (90%). Fourteen patients (73.6%) had AML with average size of 1.9 (0.4-5) cm. Medication was discontinued due to side effects in 3 (16%) patients. Treatment assessment was analyzed for 15 patients with median medication exposure 5.1 (0.8-8.5) years. Among 13 with AML, the dominant lesion decreased in size in 9 (69%) and stayed stable in 4 (31%). Greatest absolute size decrease was seen for lesions ≥2 cm. No new AML lesions formed during treatment.

CONCLUSION

Although not currently approved for this indication, everolimus appears to be well-tolerated with similar efficacy for pediatric AML as in adult AML. Use may be most warranted in children with AML ≥2 cm.

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Objectives: To present a patient material of renal angiomyolipoma (AML) with focus on the risk of bleeding during active surveillance (AS).Methods: Medical records, 1999-2014, were studied and 98 patients (80 female, 18 men) with renal AML were identified. Eleven patients had tuberous sclerosis complex (TSC). Mean age was 54 (13-89) years.Results: Sixty patients (61%) were asymptomatic at presentation, 33 (34%) presented with flank pain and five (5%) with hematuria. Retroperitoneal bleeding or hematuria was diagnosed in 20 patients with a mean AML size of 74 mm (25-200 mm). Twenty-one patients were treated with angioembolization at time of diagnosis and 25 had surgery. Forty-five patients with sporadic AML (mean size 34 mm) and six with TSC (mean size 120 mm) were selected for AS. Only one patient with sporadic AML (46 mm) had a bleeding, whereas two of the six TSC patients had bleedings from three kidneys (AML 70-300 mm). In 25 patients (49%), the AML-size increased with 2.7 mm/year in sporadic and 5.4 mm/year in TSC-associated AML. Thirteen patients were treated with AE (including all six TSC-patients) and five with surgery in 22 kidneys due to AML-size in 16, bleeding in four and suspicion of cancer in two.Conclusion: Bleeding occurred in 20% of AML at presentation. In patients selected for AS, we found a very low risk of bleeding in sporadic AML justifying our cut off size of 50 mm to trigger intervention. In TSC-associated AML individually tailored follow-up is needed due to a higher intervention rate.

Recommendations for the management of renal involvement in the tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a rare, hereditary, multisystemic disease with a broad phenotypic spectrum. Its management requires the collaboration of multiple specialists. Just as in the paediatric age, the paediatric neurologist takes on special importance; in adulthood, renal involvement is the cause of the greatest morbidity and mortality. There are several recommendations on the general management of patients with TSC but none that focuses on renal involvement. These recommendations respond to the need to provide guidelines to facilitate a better knowledge and diagnostic-therapeutic management of the renal involvement of TSC through a rational use of complementary tests and the correct use of available treatments. Their elaboration has been based on consensus within the hereditary renal diseases working group of the SEN/REDINREN (Spanish Society of Nephrology/Kidney Research Network). It has also counted on the participation of non-nephrologist specialists in TSC in order to expand the vision of the disease.

Imaging of Kidney Cysts and Cystic Kidney Diseases in Children: An International Working Group Consensus Statement

Kidney cysts can manifest as focal disease (simple and complex kidney cysts), affect a whole kidney (eg, multicystic dysplastic kidney or cystic dysplasia), or manifest as bilateral cystic disease (eg, autosomal recessive polycystic kidney disease [ARPKD] or autosomal dominant polycystic kidney disease [ADPKD]). In children, as opposed to adults, a larger proportion of kidney cysts are due to genetic diseases (eg, HNF1B nephropathy, various ciliopathies, and tuberous sclerosis complex), and fewer patients have simple cysts or acquired cystic kidney disease. The purpose of this consensus statement is to provide clinical guidance on standardization of imaging tests to evaluate kidney cysts in children. A committee of international experts in pediatric nephrology, pediatric radiology, pediatric US, and adult nephrology prepared systematic literature reviews and formulated recommendations at a consensus meeting. The final statement was endorsed by the European Society of Pediatric Radiology, the European Federation of Societies for Ultrasound in Medicine and Biology, the European Society of Pediatric Nephrology, and reviewed by the European Reference Network for Rare Kidney Diseases. Main recommendations are as follows: US is the method of choice when assessing pediatric kidney cysts, with selected indications for MRI and contrast-enhanced US. CT should be avoided whenever possible because of ionizing radiation. Renal US yields essential diagnostic information in many cases. In patients with ARPKD or other ciliopathies, abdominal US is needed for diagnosis and screening of portal hypertension. US is usually sufficient for follow-up kidney imaging, but MRI can be valuable for clinical trials in patients with ADPKD or in older children with tuberous sclerosis complex to evaluate both kidney cysts and angiomyolipomas.

Diagnosis of tuberous sclerosis complex in the fetus

Tuberous sclerosis complex is a dominantly inherited genetic disorder of striking clinical variability. It is caused by mutations in either TSC1 or TSC2 gene, which regulate cell growth and proliferation by inhibition of mTORC1 signaling. TS is characterized by the development of benign tumors in many tissues and organs and its neurological manifestations include epilepsy, autism, cognitive and behavioral dysfunction, and giant cell tumors. With mechanism-based mTOR inhibitors therapy now available for many of its manifestations, early diagnosis of TSC is very important in order to offer appropriate care, long-term surveillance and parental counseling. Fetal ultrasound and MRI imaging techniques have evolved and may capture even earlier the following TSC-associated lesions: cardiac rhabdomyomas, subependymal nodules, cortical tubers and renal cysts. Often these represent an incidental finding during a routine ultrasound. Furthermore, in the past decades prenatal molecular diagnosis of TSC has emerged as an important option for families with a known affected member; however, the existing evidence with regards to the clinical characteristics and long-term outcome of babies diagnosed prenatally with TSC is yet limited and the path that follows early TSC detection merits further research.