Treatment of Renal Angiomyolipoma and Other Hamartomas in Patients with Tuberous Sclerosis Complex

A 28-year-old patient with tuberous sclerosis associated with renal angiomyolipoma:A rare case report and literature review

Tuberous sclerosis complex (TSC) is a genetically inherited disorder distinguished by the development of numerous benign neoplasms across multiple organ systems. Renal angiomyolipoma represents 0.3% of all primary renal tumors and are classified as benign mixed mesenchymal neoplasms. In this report, we reported the clinical presentation of a 28-year-old individual who was received by the department of urology. The patient was admitted presenting with asymptomatic, macroscopic hematuria that had been ongoing for a period of 10 days. Subsequent diagnostic evaluations revealed an association between the presenting urinary condition and tuberous sclerosis complex with a concurrent renal angiomyolipom.

Arterial embolization in the treatment of multiple renal and hepatic hamartomas with spontaneous hemorrhage and 2-year follow-up: a case report

BACKGROUND

Hamartoma is a common benign tumor that usually occurs in the kidney, liver, lung, and pancreas. Large renal hamartomas may spontaneously rupture and hemorrhage, which is potentially life-threatening.

CASE PRESENTATION

This report describes a 46-year-old Han Chinese female patient with multiple renal and hepatic hamartomas with rupture and hemorrhage of giant hamartoma in the left kidney. She underwent arterial embolization three times successively, and her condition was stable during the 2-year follow-up. This report includes a review of the relevant literature CONCLUSIONS: the findings in this report and previous literature suggest that arterial embolization can not only rapidly treat hamartoma hemorrhage in the acute phase but can also effectively control multiple lesions in the long term after repeated multisite arterial embolization.

Cystic Kidney Diseases in Children and Adults: Differences and Gaps in Clinical Management

Cystic kidney diseases, when broadly defined, have a wide differential diagnosis extending from recessive diseases with a prenatal or pediatric diagnosis, to the most common autosomal-dominant polycystic kidney disease primarily affecting adults, and several other genetic or acquired etiologies that can manifest with kidney cysts. The most likely diagnoses to consider when assessing a patient with cystic kidney disease differ depending on family history, age stratum, radiologic characteristics, and extrarenal features. Accurate identification of the underlying condition is crucial to estimate the prognosis and initiate the appropriate management, identification of extrarenal manifestations, and counseling on recurrence risk in future pregnancies. There are significant differences in the clinical approach to investigating and managing kidney cysts in children compared with adults. Next-generation sequencing has revolutionized the diagnosis of inherited disorders of the kidney, despite limitations in access and challenges in interpreting the data. Disease-modifying treatments are lacking in the majority of kidney cystic diseases. For adults with rapid progressive autosomal-dominant polycystic kidney disease, tolvaptan (V2-receptor antagonist) has been approved to slow the rate of decline in kidney function. In this article, we examine the differences in the differential diagnosis and clinical management of cystic kidney disease in children versus adults, and we highlight the progress in molecular diagnostics and therapeutics, as well as some of the gaps meriting further attention.

Renal angiomyolipoma in tuberous sclerosis complex: Case series and literature review

Tuberous sclerosis complex (TSC) is a genetic disease characterized by the growth of numerous noncancerous tumors in many parts of the body mainly the skin, brain, kidneys. The prevalence of the disease is estimated to be 7 - 12 in 100,000. We report the cases of two black African women diagnosed with TSC at age 25 and 54. They both had renal angiomyolipoma, facial angiofibroma and diffuse hypochromic macules. The older patient remained stable for the 11 years following her diagnosis. But, in the second patient, the disease was more severe with a giant angiomyolipoma, complicated by renal intracystic hemorrhage leading to the patient's death 1 month after diagnosis. Renal involvement can be life-threatening in patients with TSC. The risk of fatal bleeding increases with the size of the tumor. The mTOR inhibitors and angioembolization can improve the prognosis of this disease.

Sporadic Renal Angiomyolipoma: Can We Adopt a Uniform Management Protocol?

Renal angiomyolipomas (AMLs), formerly known as PEComas (tumors showing perivascular epithelioid cell differentiation) are common benign renal masses composed of a varying ratio of fat, blood vessels, and smooth muscles. They are largely asymptomatic and diagnosed incidentally on imaging.

The adipose tissue content is the factor that gives AMLs their characteristic appearance on imaging and makes them easily identifiable. However, the fat-poor or fat-invisible varieties, which are difficult to differentiate radiologically from renal cell carcinomas (RCCs), present a diagnostic challenge. It is thus essential to establish the diagnosis and identify the atypical and hereditary cases as they require more intense surveillance and management due to their potential for malignant transformation.

Multiple management options are available, ranging from conservative approach to embolization and to the more radical option of nephrectomy. While the indications for intervention are relatively clear and aimed at a rather small cohort, the protocol for follow-up of the remainder of the cohort forming the majority of cases is not well established. The surveillance and discharge policies therefore vary between institutions and even between individual practitioners. We have reviewed the literature to establish an optimum management pathway focusing on the typical AMLs.

Embolization in Pediatric Patients: A Comprehensive Review of Indications, Procedures, and Clinical Outcomes

Embolization in pediatric patients encompasses a large spectrum of indications, ranging from the elective treatment of congenital diseases of the cardiovascular system to the urgent management of acute hemorrhagic conditions. In particular, the endovascular treatment of central and peripheral vascular malformations and hypervascular tumors represents a wide chapter for both congenital and acquired situations. Thanks to the progressive availability of low-profile endovascular devices and new embolic materials, the mini-invasive approach has gradually overtaken surgery. In this review, the main embolization procedures will be illustrated and discussed, with a focus on clinical indications and expected outcomes. The most recent mini-invasive techniques will be described, with hints on the cutting-edge devices and embolic materials.

Defining the Magnetic Resonance Features of Renal Lesions and Their Response to Everolimus in a Transgenic Mouse Model of Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an inherited genetic disorder characterized by mutations in TSC1 or TSC2 class of tumor suppressers which impact several organs including the kidney. The renal manifestations are usually in the form of angiomyolipoma (AML, in 80% of the cases) and cystadenomas. mTOR inhibitors such as rapamycin and everolimus have shown efficacy in reducing the renal tumor burden. Early treatment prevents the progression of AML; however, the tumors regrow upon cessation of therapy implying a lifelong need for monitoring and management of this morbid disease. There is a critical need for development of imaging strategies to monitor response to therapy and progression of disease which will also facilitate development of newer targeted therapy. In this study we evaluated the potential of multiparametric ¹H magnetic resonance imaging (mpMRI) to monitor tumor response to therapy in a preclinical model of TSC, the transgenic mouse A/J Tsc2^+/-. We found 2-dimensional T₂-weighted sequence with 0.5 mm slice thickness to be optimal for detecting renal lesions as small as 0.016 mm³. Baseline characterization of lesions with MRI to assess physiological parameters such as cellularity and perfusion is critical for distinguishing between cystic and solid lesions. Everolimus treatment for three weeks maintained tumor growth at 36% from baseline, while control tumors displayed steady growth and were 70% larger than baseline at the end of therapy. Apparent diffusion coefficient, T₁ values and normalized T₂ intensity changes were also indictive of response to treatment. Our results indicate that standardization and implementation of improved MR imaging protocols will significantly enhance the utility of mpMRI in determining the severity and composition of renal lesions for better treatment planning.

Analysis of Clinical Features and Next-Generation Sequencing of 12 Tuberous Sclerosis Families in China

Background

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disease with systemic organ involvement. So far, only a few TSC families in China have been reported. Therefore, more data on the clinical and genetic features of TSC families are required.

Materials and Methods

We retrospectively analyzed 12 TSC family probands and their family members. Next-generation sequencing (NGS) has been applied to confirm the type of TSC mutation along with a detailed physical examination.

Results

In this study, twenty-seven patients in 12 TSC families were reported, including 12 male and 15 female patients, aged 8-67 years. Skin lesions were detected among all patients with TSC, including 25 cases of facial angiofibromas, 18 cases of hypomelanotic macules, 15 cases of ungual fibromas, and 13 cases of shagreen patch. Other clinical features were also revealed: 14 cases of renal angiomyolipoma, 6 cases of subependymal nodules (SENs), and 3 cases of lymphangioleiomyomatosis. All twenty-seven patients with TSC were tested by NGS. Totally, TSC2 mutations were reported in 19 cases (7 frameshift mutations, 10 nonsense mutations, and 2 missense mutations), TSC1 mutations were reported in 4 cases (4 nonsense mutations), and 4 cases were genetically negative. The novel causal mutations (TSC2: c.208dup, c.1874C > G, c.1852del) identified in three families were first reported in TSC.

Conclusion

Our findings expand the mutation spectrum of patients with TSC in China. The clinical characteristics can vary among patients with TSC with the same pathogenic mutation. The genetic results and summary of clinical features of 12 TSC families contribute to a more accurate diagnosis and further genetic counseling.

A tissue-bioengineering strategy for modeling rare human kidney diseases in vivo

The lack of animal models for some human diseases precludes our understanding of disease mechanisms and our ability to test prospective therapies in vivo. Generation of kidney organoids from Tuberous Sclerosis Complex (TSC) patient-derived-hiPSCs allows us to recapitulate a rare kidney tumor called angiomyolipoma (AML). Organoids derived from TSC2-/- hiPSCs but not from isogenic TSC2+/- or TSC2+/+ hiPSCs share a common transcriptional signature and a myomelanocytic cell phenotype with kidney AMLs, and develop epithelial cysts, replicating two major TSC-associated kidney lesions driven by genetic mechanisms that cannot be consistently recapitulated with transgenic mice. Transplantation of multiple TSC2-/- renal organoids into the kidneys of immunodeficient rats allows us to model AML in vivo for the study of tumor mechanisms, and to test the efficacy of rapamycin-loaded nanoparticles as an approach to rapidly ablate AMLs. Collectively, our experimental approaches represent an innovative and scalable tissue-bioengineering strategy for modeling rare kidney disease in vivo.

A 47-Year-Old Woman With Pulmonary Nodules and Facial Hemispasms

CASE PRESENTATION

A 47-year-old woman visited her primary physician for a health check, and some radiographic abnormalities were detected. She was referred to our division for further management. In recent years, she had become conscious of occasional facial hemispasms. She denied respiratory symptoms, smoking, alcohol consumption, and any particle inhalation. She had undergone oophorectomy and platinum-based chemotherapy because of ovarian cancer (serous cystadenocarcinoma stage Ⅰa) at the age of 29 years, with no recurrence for 17 years. The patient was diagnosed with rheumatoid arthritis (RA) 5 years before being seen by us and had been treated with bucillamine. No signs of RA progression were evident, and the only used antirheumatic drug was bucillamine. The patient had no history of use of immune-modulating drugs or immunosuppressants. No previous chest radiographs or CT had been performed.

Rare inherited kidney diseases: an evolving field in Nephrology

There are more than 150 different rare genetic kidney diseases. They can be classified according to diagnostic findings as (i) disorders of growth and structure, (ii) glomerular diseases, (iii) tubular, and (iv) metabolic diseases. In recent years, there has been a shift of paradigm in this field. Molecular testing has become more accessible, our understanding of the underlying pathophysiologic mechanisms of these diseases has evolved, and new therapeutic strategies have become more available. Therefore, the role of nephrologists has progressively shifted from a mere spectator to an active player, part of a multidisciplinary team in the diagnosis and treatment of these disorders. This article provides an overview of the recent advances in rare hereditary kidney disorders by discussing the genetic aspects, clinical manifestations, diagnostic, and therapeutic approaches of some of these disorders, named familial focal and segmental glomerulosclerosis, tuberous sclerosis complex, Fabry nephropathy, and MYH-9 related disorder.

The tuberous sclerosis complex-associated giant renal angiomyolipoma: A case report

Renal angiomyolipoma (RAML), also referred to as renal hamartoma, is a rare benign tumor. There are two types of RAML, which include the tuberous sclerosis complex (TSC)-associated type and the sporadic type. TSC is an autosomal dominant genetic disease characterized by the growth of benign tumors in the skin, brain, kidneys, lung and heart. TSC leads to organ dysfunction, as the normal parenchyma is replaced by a variety of cell types. The current study presents a case of giant RAML in a 20-year-old female, who was hospitalized for epileptic seizures. Large abdominal lesions were detected during hospitalization. Subsequently, she underwent open mass resection and right kidney partial resection. Postoperative pathological examination confirmed that the mass was angiomyolipoma.

Use and outcomes of kidneys from donors with renal angiomyolipoma: A systematic review

Background:

Renal angiomyolipoma (AML) is the most frequent mesenchymal tumor of the kidney. Although there is a rare possibility of malignant transformation of AML, this risk has not been studied in immunosuppressed patients. The safety of donors with AML and their kidney transplant recipients has not been well established.

Methods:

A literature search was conducted utilizing MEDLINE, EMBASE, and Cochrane databases from inception through May 15, 2018 (updated on October 2019). We included studies that reported the outcomes of kidney donors with AML or recipients of donor with AML. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018095157).

Results:

Fourteen studies with a total of 16 donors with AML were identified. None of the donors had a diagnosis of tuberous sclerosis complex (TSC), pulmonary lymphangioleiomyomatosis (LAM), or epithelioid variant of AML. Donor age ranged from 35 to 77 years, and recipient age ranged from 27 to 62 years. Ninety-two percent of the donors were female. Only 8% were deceased donor renal transplant. The majority underwent ex vivo resection (65%) before transplantation, followed by no resection (18%), and the remaining had in vivo resection. Tumor size varied from 0.4 cm to 7 cm, and the majority (87%) were localized in the right kidney. Follow-up time ranged from 1 to 107 months. Donor creatinine prenephrectomy ranged 0.89–1.1 mg/dL and postnephrectomy creatinine 1.0–1.17 mg/dL. In those who did not have resection of the AML, tumor size remained stable. None of the donors with AML had end-stage renal disease or died at last follow-up. None of the recipients had malignant transformation of AML.

Conclusion:

These findings are reassuring for the safety of donors with AML (without TSC or LAM) as well as their recipients without evidence of malignant transformation of AML. As such, this can also positively impact the donor pool by increasing the number of available kidneys.

Angiomyolipoma of the kidney: from simple hamartoma to complex tumour

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

Renal Manifestations of Tuberous Sclerosis Complex: Key Findings From the Final Analysis of the TOSCA Study Focussing Mainly on Renal Angiomyolipomas

Renal angiomyolipomas are one of the most common renal manifestations in patients with tuberous sclerosis complex (TSC), with potentially life-threatening complications and a poor prognosis. Despite the considerable progress in understanding TSC-associated renal angiomyolipomas, there are no large scale real-world data. The aim of our present study was to describe in detail the prevalence and outcome of renal angiomyolipomas in patients with TSC, enrolled into the TuberOus SClerosis registry to increase disease Awareness (TOSCA) from 170 sites across 31 countries worldwide. We also sought to evaluate the relationship of TSC-associated renal angiomyolipomas with age, gender and genotype. The potential risk factors for renal angiomyolipoma-related bleeding and chronic kidney disease (CKD) were studied in patients who participated in the TOSCA renal angiomyolipoma substudy. Of the 2,211 eligible patients, 1,062 (48%) reported a history of renal angiomyolipomas. The median age of TSC diagnosis for the all subjects (n = 2,211) was 1 year. The median age of diagnosis of renal angiomyolipoma in the 1,062 patients was 13 years. Renal angiomyolipomas were significantly more prevalent in female patients (p < 0.0001). Rates of angiomyolipomas >3 cm (p = 0.0119), growing lesions (p = 0.0439), and interventions for angiomyolipomas (p = 0.0058) were also higher in females than males. Pre-emptive intervention for renal angiomyolipomas with embolisation, surgery, or mammalian target of rapamycin (mTOR) inhibitor may have abolished the gender difference in impaired renal function, hypertension, and other complications. The rate of interventions for angiomyolipomas was less common in children than in adults, but interventions were reported in all age groups. In the substudy of 76 patients the complication rate was too low to be useful in predicting risk for more severe CKD. In addition, in this substudy no patient had a renal hemorrhage after commencing on an mTOR inhibitor. Our findings confirmed that renal angiomyolipomas in subjects with TSC1 mutations develop on average at the later age, are relatively smaller in size and less likely to be growing; however, by age 40 years, no difference was observed in the percentage of patients with TSC1 and TSC2 mutations needing intervention. The peak of appearance of new renal angiomyolipomas was observed in patients aged between 18 and 40 years, but, given that angiomyolipomas can occur later, lifelong surveillance is necessary. We found that pre-emptive intervention was dramatically successful in altering the outcome compared to historical controls; with high pre-emptive intervention rates but low rates of bleeding and other complications. This validates the policy of surveillance and pre-emptive intervention recommended by clinical guidelines.

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.

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.

Juvenile xanthogranuloma as a new type of skin lesions in tuberous sclerosis complex

OBJECTIVE

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disease with many manifestations, and it involves any organ. In this study, we report a TSC patient with new type skin lesions.

METHODS

A 7-month-old TSC boy with multiple cutaneous nodules was admitted in our hospital. We collected the clinical data of the patient. We performed biopsy of cutaneous nodules and whole-exome sequencing in both paraffin block tissue and blood samples.

RESULTS

The patient presented with a 2 month history of gradual growth multiple cutaneous nodules. He had cardiac rhabdomyoma, subependymal giant cell astrocytoma (SEGA) and hypomelanotic macules. The pathological finding of cutaneous nodules was consistent with juvenile xanthogranuloma (JXG). After 3 months of sirolimus treatment, the multiple nodules disappeared. The whole-exome sequencing identified TSC1 (c.2356C > T, p.R786*) mutation in both paraffin block tissue and blood samples. We overturned the original pathological diagnosis and finally identified JXG as a new type of skin lesions in TSC.

CONCLUSION

This is the first report on the occurrence of JXG skin lesions in TSC patient. Genetic testing is necessary in JXG. These findings expand the phenotype of skin in patients with TSC and contribute to the elucidation of JXG pathogenesis and treatment.

A brain proteomic investigation of rapamycin effects in the Tsc1+/- mouse model

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare monogenic disorder characterized by benign tumors in multiple organs as well as a high prevalence of epilepsy, intellectual disability and autism. TSC is caused by inactivating mutations in the TSC1 or TSC2 genes. Heterozygocity induces hyperactivation of mTOR which can be inhibited by mTOR inhibitors, such as rapamycin, which have proven efficacy in the treatment of TSC-associated symptoms. The aim of the present study was (1) to identify molecular changes associated with social and cognitive deficits in the brain tissue of Tsc1+/- mice and (2) to investigate the molecular effects of rapamycin treatment, which has been shown to ameliorate genotype-related behavioural deficits.

METHODS

Molecular alterations in the frontal cortex and hippocampus of Tsc1+/- and control mice, with or without rapamycin treatment, were investigated. A quantitative mass spectrometry-based shotgun proteomic approach (LC-MSE) was employed as an unbiased method to detect changes in protein levels. Changes identified in the initial profiling stage were validated using selected reaction monitoring (SRM). Protein Set Enrichment Analysis was employed to identify dysregulated pathways.

RESULTS

LC-MSE analysis of Tsc1+/- mice and controls (n = 30) identified 51 proteins changed in frontal cortex and 108 in the hippocampus. Bioinformatic analysis combined with targeted proteomic validation revealed several dysregulated molecular pathways. Using targeted assays, proteomic alterations in the hippocampus validated the pathways "myelination", "dendrite," and "oxidative stress", an upregulation of ribosomal proteins and the mTOR kinase. LC-MSE analysis was also employed on Tsc1+/- and wildtype mice (n = 34) treated with rapamycin or vehicle. Rapamycin treatment exerted a stronger proteomic effect in Tsc1+/- mice with significant changes (mainly decreased expression) in 231 and 106 proteins, respectively. The cellular pathways "oxidative stress" and "apoptosis" were found to be affected in Tsc1+/- mice and the cellular compartments "myelin sheet" and "neurofilaments" were affected by rapamycin treatment. Thirty-three proteins which were altered in Tsc1+/- mice were normalized following rapamycin treatment, amongst them oxidative stress related proteins, myelin-specific and ribosomal proteins.

CONCLUSIONS

Molecular changes in the Tsc1+/- mouse brain were more prominent in the hippocampus compared to the frontal cortex. Pathways linked to myelination and oxidative stress response were prominently affected and, at least in part, normalized following rapamycin treatment. The results could aid in the identification of novel drug targets for the treatment of cognitive, social and psychiatric symptoms in autism spectrum disorders. Similar pathways have also been implicated in other psychiatric and neurodegenerative disorders and could imply similar disease processes. Thus, the potential efficacy of mTOR inhibitors warrants further investigation not only for autism spectrum disorders but also for other neuropsychiatric and neurodegenerative diseases.