Skin lesions in children with tuberous sclerosis complex: their prevalence, natural course, and diagnostic significance

A case of tuberous sclerosis complex revealed by epilepsy

Tuberous sclerosis complex is a multisystem genetic disease with autosomal dominant inheritance, characterized by the development of benign tumors known as hamartomas that affect multiple organs. It is a condition with a wide phenotypic spectrum, and its clinical presentation varies over time within the same individual. Hence, the importance of early screening and rigorous monitoring of evolving clinical manifestations. Diagnosis can occur at any age. These tumors are generally benign, but their size and location can have a significant impact on the prognosis and, in some cases, even on life expectancy. Cardiac, neurological, and cutaneous manifestations are most common in childhood. The onset of early and severe epilepsy within the first year of life is associated with neurodevelopmental disorders that impact the quality of life for affected individuals and their families. We present a case of a 22-year-old female patient experiencing inaugural epileptic seizures in adulthood, with magnetic resonance imaging revealing subependymal hamartomas, cortical tubers and radial migration bands accompanied by polycystic kidney disease; the diagnosis of tuberous sclerosis complex was established based on the association of these lesions, which constitute major and minor criteria.

Congenital single kidney in tuberous sclerosis complex (Bourneville disease)

Introduction

Bournevile disease is a rare global condition that presents a diagnostic challenge due to its diverse multisystemic involvement.

Case presentation

This report presents the case of a 14-year-old male with a medical history of congenital single kidney, heart rate abnormalities, Bournevile disease with cognitive deficits, brain lesions, and dermatological features. The patient presented with sudden onset renal angiolipomatosis, and the diagnosis was based on specific computed tomography (CT) findings. Despite having these complex medical conditions, the patient had never been admitted to the hospital since infancy, and treatment was limited to surveillance only.

Clinical discussion

Bourneville disease is a multisystemic disease that affects several organ systems within the human body and thus demands multidisciplinary approach in the treatment and follow-up options.

Conclusion

This case report highlights Bournevile disease in a patient with a congenital single kidney, a rare finding that further complicates the disease. It emphasises the importance of recognising and managing this condition to ensure appropriate care for affected individuals.

The Clinical and Paraclinical Manifestations of Tuberous Sclerosis in an Omani Female Patient

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Neurological and Dermatological Manifestations of Tuberous Sclerosis Complex: Report from a Romanian Tertiary Hospital Cohort

Tuberous sclerosis complex is a rare multisystem genetic disorder characterized by multiorgan involvement, frequently associated with intellectual impairment and epilepsy. The aim of our study was to describe the neurological and dermatological manifestations of TSC in 32 adult patients (of whom 19 were females) who attended the Neurology and Nephrology Clinics of Fundeni Clinical Institute in Romania from 2015 to 2020. Seventeen patients were diagnosed with epilepsy, nine patients had intellectual impairment, and complete neuroimaging was available for twenty-two patients. As expected, the most frequent dermatological lesions were cutaneous angiofibromas in 20 patients, but with a lower frequency than described in the current literature. Statistical analysis was performed considering the small number of patients. Cortical tubers in neuroimaging seemed to be associated with the diagnosis of epilepsy, while subependymal nodules represented a risk factor for intellectual impairment. Males showed a larger number of dermatological types of lesions, especially café -au-lait patches. Interestingly, we found a statistically significant positive association between epilepsy and the presence of cutaneous angiofibromas, as well as total dermatological involvement. Females had significantly higher Charlson comorbidity index scores, indicating a higher burden of disease. Everolimus seemed to be a well-tolerated treatment and showed promising results in controlling epileptic seizures alone in two patients. More studies, with the inclusion of a larger number of patients, are needed to confirm these results.

Paradigm shift in the treatment of tuberous sclerosis: Effectiveness of everolimus

Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterised by abnormal cell proliferation and differentiation that affects multiple organs and can lead to the growth of hamartomas. Tuberous sclerosis complex is caused by the disinhibition of the protein mTOR (mammalian target of rapamycin). In the past, various therapeutic approaches, even if only symptomatic, have been attempted to improve the clinical effects of this disease. While all of these therapeutic strategies are useful and are still used and indicated, they are symptomatic therapies based on the individual symptoms of the disease and therefore not fully effective in modifying long-term outcomes. A new therapeutic approach is the introduction of allosteric inhibitors of mTORC1, which allow restoration of metabolic homeostasis in mutant cells, potentially eliminating most of the clinical manifestations associated with Tuberous sclerosis complex. Everolimus, a mammalian target of the rapamycin inhibitor, is able to reduce hamartomas, correcting the specific molecular defect that causes Tuberous sclerosis complex. In this review, we report the findings from the literature on the use of everolimus as an effective and safe drug in the treatment of TSC manifestations affecting various organs, from the central nervous system to the heart.

Kinase Inhibitors in Genetic Diseases

Over the years, several studies have shown that kinase-regulated signaling pathways are involved in the development of rare genetic diseases. The study of the mechanisms underlying the onset of these diseases has opened a possible way for the development of targeted therapies using particular kinase inhibitors. Some of these are currently used to treat other diseases, such as cancer. This review aims to describe the possibilities of using kinase inhibitors in genetic pathologies such as tuberous sclerosis, RASopathies, and ciliopathies, describing the various pathways involved and the possible targets already identified or currently under study.

Impact of facial angiofibromas in tuberous sclerosis complex and reported efficacy of available treatments

Tuberous Sclerosis Complex (TSC) is a genetic condition which leads to a loss of inhibition of cellular growth. Facial angiofibromas (FAs) are hamartomatous growths associated with TSC that appear as multiple small, erythematous papules on the skin of the face and may resemble more severe forms of acne vulgaris. FAs have been reported in up to 74.5% of pediatric TSC patients, rising to up to 88% in adults >30 years old. They have not been closely studied, potentially overshadowed by other, systemic features of TSC. To investigate the impact of FAs, a common clinical feature for patients with TSC, we performed a non-interventional study in the form of a survey, completed by people living with TSC and FAs, or their caregiver as a proxy, if necessary. Patients were recruited via patient organizations in the UK and Germany. Data was received from 108 families in the UK (44 patients, 64 caregivers) and 127 families in Germany (50 patients, 64 caregivers). Exclusion criteria were those outside of 6-89 years, those without FAs, or those enrolled in a clinical trial. Where caregivers reported on behalf of an individual unable to consent, they were required to be adults (>18 years). Patient experience in the design of the survey was considered from practical and logistical perspectives with survey questions assessing multiple aspects relating to FAs including age of onset, perceived severity, treatments, perceived efficacy of treatments and perceived psychosocial impacts of the FAs. The psychosocial impacts of FAs for the individuals as well as for caregivers were explored in terms of social, occupational and leisure activities. Results of the survey demonstrated that for those with TSC-related moderate or severe FAs, there is an impact on quality of life and psychosocial impacts in the form of anxiety and depression. This finding was also noted by caregivers of TSC individuals in these categories. The treatment most frequently received to improve FAs, topical rapamycin/sirolimus, was found to be successful in the majority of those who received it.

Value of a café-au-lait macules screening clinic: Experience from The Hospital for Sick Children in Toronto

BACKGROUND/OBJECTIVES

Café-au-lait macules (CALMs) are a characteristic feature of neurofibromatosis type 1 (NF1), but also occur in other genetic disorders. Differential diagnosis of CALMs remains challenging and can be stressful for families. We sought to examine the role of an established CALMs screening clinic in diagnosing CALMs-related disorders.

METHOD

We retrospectively reviewed patients seen between July 2012 and January 2019 in a CALMs screening clinic at The Hospital for Sick Children, a tertiary pediatric hospital in Toronto, Canada. Pediatric patients were referred because of multiple CALMs or suspected NF1. Selection was based on a chronological referral sample with no exclusions. A pediatric dermatologist examined all patients for CALMs and NF1 manifestations. Genetic testing was offered to confirm a clinical diagnosis or when clinical findings were inconclusive.

RESULTS

Three hundred patients, of which 152 (50.7%) were female and had a mean age of 5.6 ± 4.8 years were seen during the study period. NF1 was diagnosed in 76 (25.3%) patients, mosaic NF1 in 38 (12.7%) patients, and 8 (2.7%) patients received other genetic diagnoses. One hundred and twelve (37.3%) patients were diagnosed with isolated CALMs not associated with an underlying genetic disease. Furthermore, 36 (12%) of our patients did not have CALMs.

CONCLUSIONS

The CALMs screening clinic aided in the early diagnosis of genetic disorders such as NF1 and distinguished CALMs from other hyperpigmented lesions. We encourage the adoption of this clinic model in referral centers to streamline and optimize care of patients with presumptive diagnosis of CALMs.

Beyond the "3 Ps": A critical appraisal of the non-endocrine manifestations of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1), an autosomal-dominantly inherited tumor syndrome, is classically defined by tumors arising from the "3 Ps": Parathyroids, Pituitary, and the endocrine Pancreas. From its earliest descriptions, MEN1 has been associated with other endocrine and non-endocrine neoplastic manifestations. High quality evidence supports a direct association between pathogenic MEN1 variants and neoplasms of the skin (angiofibromas and collagenomas), adipose tissue (lipomas and hibernomas), and smooth muscle (leiomyomas). Although CNS tumors, melanoma, and, most recently, breast cancer have been reported as MEN1 clinical manifestations, the published evidence to date is not yet sufficient to establish causality. Well-designed, multicenter prospective studies will help us to understand better the relationship of these tumors to MEN1, in addition to verifying the true prevalence and penetrance of the well-documented neoplastic associations. Nevertheless, patients affected by MEN1 should be aware of these non-endocrine manifestations, and providers should be encouraged always to think beyond the "3 Ps" when treating an MEN1 patient.

"Molluscum" Conditions in Dermatology

In dermatology, the word “molluscum” is used as a prefix for infective and non-infective conditions. The term is used to describe soft papules or nodules with or without central umbilication, which is not a necessary qualification. This article attempts to summarise the conditions in dermatology with the epithet “molluscum” and discuss them in brief.

Updated Approach to Patients with Multiple Café au Lait Macules

Café au lait macules (CALMs) are a normal and frequent finding in the general population, but multiple CALMs raise the possibility of an underlying neurocutaneous disease like neurofibromatosis type I. Certain features of CALMs like number, size, shape, and distribution are important in identifying children at higher risk of having a neurocutaneous disorder or another genetic disorder. Genetic testing can be especially helpful in establishing a diagnosis in atypical presentations, or when the child is young and other features of the disease aside from CALMs have not manifested.

Histological Patterns of Skin Lesions in Tuberous Sclerosis Complex: A Panorama

Tuberous Sclerosis Complex (TSC) is a multisystem genetic disease characterized by cutaneous and extracutaneous hamartomas. The diagnosis is based on the association of major and minor criteria, defined by a consensus conference updated in 2012. The clinical examination of the skin is crucial because seven diagnostic criteria are dermatological: four major (hypomelanotic macules, angiofibroma or fibrous cephalic plaques, ungual fibromas, shagreen patches) and three minor criteria (confetti skin lesions, dental enamel pits, intraoral fibromas). Skin biopsy is commonly performed to assert the diagnosis of TSC when the clinical aspect is atypical. Histopathology of TSC cutaneous lesions have been poorly reported until now. In this article, we review the histologic features described in the literature and share our experience of TSC skin biopsies in our pediatric hospital specialized in genetic disorders. Both hypomelanotic lesions and cutaneous hamartomas (angiofibroma/fibrous cephalic plaques, ungual fibromas, shagreen patches) are discussed, including the recent entity called folliculocystic and collagen hamartoma, with a special emphasis on helpful clues for TSC in such lesions.

Histopathological features of fibrous cephalic plaques in tuberous sclerosis complex

AIMS

Fibrous cephalic plaques (FCPs) in individuals with tuberous sclerosis complex (TSC) may be excised for cosmetic reasons or biopsied to confirm lesion identification and TSC diagnosis. The aim of this study was to determine the range of histopathological features of FCPs.

METHODS AND RESULTS

A retrospective analysis was conducted on 119 adults with TSC. Twenty-one lesions from 16 individuals were evaluated by a dermatopathologist. Additionally, we assessed whether lesion colour or histology varied by anatomical location. Seventy-six lesions were observed in 36 of 119 individuals. Erythematous lesions were more commonly found on the forehead, face or neck than on the scalp (odds ratio = 12.6, P = 0.0001). Thickened and disorganised collagen fibre bundles were present in 95% (20/21) of lesions. Perifollicular fibrosis was observed in 95% (20/21) of lesions, enhanced vascularity was observed in 52% (11/21) of lesions, and features of fibrofolliculoma were observed in 43% (9/21) of lesions. Other abnormalities included features similar to trichofolliculoma, follicular-derived, infundibular-type cysts, and abnormally arranged primitive hair follicles.

CONCLUSIONS

FCPs in TSC show thickened bundles of collagen, and hamartomatous changes involving hair follicles. Recognition of these histopathological features may raise the possibility of unsuspected TSC or confirm FCP identification.

[Tuberous sclerosis system: A review]

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

Miliary fibromas in tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex (TSC) is a hamartoma syndrome characterized by multiple skin lesions, such as angiofibromas, shagreen patch and miliary fibromas (MiF).

OBJECTIVE

To determine the clinical and histological features of MiF.

METHODS

A retrospective analysis was conducted on 133 adults with TSC. Photography was used to characterize the appearance and location of MiF. Histological features in five skin samples from four individuals were evaluated by a board-certified dermatopathologist.

RESULTS

MiF were observed in 19 of 133 (14%) individuals with TSC. MiF were 1- to 3-mm skin-coloured, sessile papules scattered on the back and rarely buttocks or thighs. Most were scattered in a bilaterally symmetric distribution, but others were asymmetric or associated with a shagreen patch. Histological features of MiF included expansion of the papillary and periadnexal dermis with variable hamartomatous abnormalities involving adjacent epithelial components.

CONCLUSIONS

MiF are distinct from other cutaneous lesions in TSC such as shagreen patches and angiofibromas. Recognition of this entity is important in defining the spectrum of TSC disease and reassuring individuals with TSC that these lesions are benign.

Familial Nervous System Tumor Syndromes

PURPOSE OF REVIEW

Although sporadic primary neoplasms account for the majority of nervous system tumors, familial nervous system tumor syndromes are important and clinically relevant conditions for the neurologist to understand. This article reviews common inherited nervous system tumor syndromes including neurofibromatosis type 1, neurofibromatosis type 2, schwannomatosis, tuberous sclerosis complex, and von Hippel-Lindau syndrome. The epidemiology, genetics, approach to diagnosis, neurologic and nonneurologic manifestations, and management options are reviewed.

RECENT FINDINGS

Awareness of the more common and clinically relevant familial nervous system tumor syndromes is important. These conditions teach us about the underlying biology that drives tumor development in the central and peripheral nervous systems including peripheral nerve sheath tumors (eg, neurofibroma, schwannoma), meningioma, vestibular schwannoma, subependymal giant cell astrocytoma, and hemangioblastoma. Knowledge of the clinical manifestations ensures that the neurologist will be able to diagnose these conditions, recommend appropriate surveillance, refer to specialists, and support optimal management. Important discoveries in the role of the underlying genetics have contributed to the launch of several novel drug trials for these tumors, which are changing therapeutic options for patients.

SUMMARY

Familial nervous system tumor syndromes are uncommon conditions that require specialized surveillance and management strategies. Coordination across a multidisciplinary team that includes neurologists, neuro-oncologists, radiologists, neurosurgeons, radiation oncologists, otolaryngologists, pathologists, neuropsychologists, physical medicine and rehabilitation specialists, and geneticists is necessary for the optimal treatment of these patients.

Acne in the first three decades of life: An update of a disorder with profound implications for all decades of life

Acne vulgaris is a chronic, inflammatory, skin condition that involves the pilosebaceous follicles and is influenced by a variety of factors including genetics, androgen-stimulation of sebaceous glands with abnormal keratinization, colonization with Cutibacterium acnes (previously called Propionibacterium acnes), and pathological immune response to inflammation. Acne can occur at all ages and this discussion focuses on the first three decades of life. Conditions that are part of the differential diagnosis and/or are co-morbid with acne vulgaris are also considered. Acne in the first year of life includes neonatal acne (acne neonatorum) that presents in the first four weeks of life and infantile acne that usually presents between 3 and 6 months of the first year of life with a range of 3 to 16 months after birth. Acne rosacea is a chronic, inflammatory, skin condition that is distinct from acne vulgaris, typically presents in adults, and has four main types: erythemato-telangiectatic, papulopustular, phymatous and ocular. Treatment options for acne vulgaris include topical retinoids, topical benzoyl peroxide, antibiotics (topical, oral), oral contraceptive pills, isotretinoin, and others. Management must consider the increasing impact of antibiotic resistance in the 21st century. Psychological impact of acne can be quite severe and treatment of acne includes awareness of the potential emotional toll this disease may bring to the person with acne as well as assiduous attention to known side effects of various anti-acne medications (topical and systemic). Efforts should be directed at preventing acne-caused scars and depigmentation on the skin as well as emotional scars within the person suffering from acne.

Impacting development in infants with tuberous sclerosis complex: Multidisciplinary research collaboration

The Tuberous Sclerosis Complex Autism Center of Excellence Network (TACERN) is a 6-site collaborative conducting longitudinal research on infants with tuberous sclerosis complex (TSC), focused on identifying early biomarkers for autism spectrum disorder (ASD). A multidisciplinary research team that includes the specialties of psychology, neurology, pediatrics, medical genetics, and speech-language pathology, its members work together to conduct studies on neurological status, brain structure and function, neurodevelopmental phenotype, and behavioral challenges in this population. This article provides insights into the roles of the multidisciplinary multisite team and lessons learned from the collaboration, in terms of research as well as training of future researchers and clinicians. In addition, the authors detail the major findings to date, including those related to the identification and measurement of early symptoms of ASD, relationship between seizures and early development, and early biomarkers for epilepsy and developmental delay in infants and young children with TSC. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

First comprehensive TSC1/TSC2 mutational analysis in Mexican patients with Tuberous Sclerosis Complex reveals numerous novel pathogenic variants

The aim of this study was to improve knowledge of the mutational spectrum causing tuberous sclerosis complex (TSC) in a sample of Mexican patients, given the limited information available regarding this disease in Mexico and Latin America. Four different molecular techniques were implemented to identify from single nucleotide variants to large rearrangements in the TSC1 and TSC2 genes of 66 unrelated Mexican-descent patients that clinically fulfilled the criteria for a definitive TSC diagnosis. The mutation detection rate was 94%, TSC2 pathogenic variants (PV) prevailed over TSC1 PV (77% vs. 23%) and a recurrent mutation site (hotspot) was observed in TSC1 exon 15. Interestingly, 40% of the identified mutations had not been previously reported. The wide range of novels PV made it difficult to establish any genotype-phenotype correlation, but most of the PV conditioned neurological involvement (intellectual disability and epilepsy). Our 3D protein modeling of two variants classified as likely pathogenic demonstrated that they could alter the structure and function of the hamartin (TSC1) or tuberin (TSC2) proteins. Molecular analyses of parents and first-degree affected family members of the index cases enabled us to distinguish familial (18%) from sporadic (82%) cases and to identify one case of apparent gonadal mosaicism.

Phakomatoses

Phakomatoses present with characteristic findings on the skin, central or peripheral nervous system, and tumors. Neurofibromatosis type 1 is the most common syndrome and is characterized by Café-au-lait macules, intertriginous freckling, Lisch nodules, and tumors including neurofibromas, malignant peripheral nerve sheath tumors, and gliomas. Tuberous Sclerosis Complex is characterized by benign hamartomas presenting with hypomelanotic macules, shagreen patches, angiofibromas, confetti lesions and tumors including cortical tubers, subependymal nodules, subependymal giant cell astrocytomas and tumors of the kidney, lung, and heart. Managing these disorders requires disease specific supportive care, tumor monitoring, surveillance for selected cancers, and treatment of comorbid conditions.

A systematic review on the burden of illness in individuals with tuberous sclerosis complex (TSC)

Objective

This review will summarize current knowledge on the burden of illness (BOI) in tuberous sclerosis complex (TSC), a multisystem genetic disorder manifesting with hamartomas throughout the body, including mainly the kidneys, brain, skin, eyes, heart, and lungs.

Methods

We performed a systematic analysis of the available literature on BOI in TSC according to the PRISMA guidelines. All studies irrespective of participant age that reported on individual and societal measures of disease burden (e.g. health care resource use, costs, quality of life) were included.

Results

We identified 33 studies reporting BOI in TSC patients. Most studies (21) reported health care resource use, while 14 studies reported quality of life and 10 studies mentioned costs associated with TSC. Only eight research papers reported caregiver BOI. Substantial BOI occurs from most manifestations of the disorder, particularly from pharmacoresistant epilepsy, neuropsychiatric, renal and skin manifestations. While less frequent, pulmonary complications also lead to a high individual BOI. The range for the mean annual direct costs varied widely between 424 and 98,008 International Dollar purchasing power parities (PPP-$). Brain surgery, end-stage renal disease with dialysis, and pulmonary complications all incur particularly high costs. There is a dearth of information regarding indirect costs in TSC. Mortality overall is increased compared to general population; and most TSC related deaths occur as a result of complications from seizures as well as renal complications. Long term studies report mortality between 4.8 and 8.3% for a follow-up of 8 to 17.4 years.

Conclusions

TSC patients and their caregivers have a high burden of illness, and TSC patients incur high costs in health care systems. At the same time, the provision of inadequate treatment that does not adhere to published guidelines is common and centralized TSC care is received by no more than half of individuals who need it, especially adults. Further studies focusing on the cost effectiveness and BOI outcomes of coordinated TSC care as well as of new treatment options such as mTOR inhibitors are necessary.

Use of Topical Rapamycin as Maintenance Treatment after a Single Session of Fractionated CO2 Laser Ablation: A Method to Enhance Percutaneous Drug Delivery

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous disorder with an incidence of approximately 1 in 5,000 to 10,000 live births. TSC has various clinical manifestations such as multiple hamartomas in systemic organs, including the skin. Angiofibromas are the most common skin lesions in patients with TSC. Although benign, angiofibromas develop in childhood and puberty, and can be psychosocially disfiguring for patients. Skin lesions in TSC, specifically angiofibromas, have no significant risk of malignant transformation after puberty; thus, they require no treatment if not prominent. However, the presentation of TSC is important owing to its impact on patient cosmesis. Surgical treatment and laser therapy are the mainstream treatments for angiofibromas. Although the evidence is limited, topical mammalian target of rapamycin inhibitors such as sirolimus (rapamycin) are effective in facial angiofibroma treatment. We describe an adult patient with an angiofibroma who had an excellent response to treatment with topical rapamycin after a single session of carbon dioxide (CO₂) laser ablation. The patient showed no sign of relapse or recurring lesions for a year. CO₂ laser ablation may serve as a new paradigm of treatment for angiofibromas in TSC. Since the selection of laser devices can be limited for some institutions, we suggest a rather basic but highly effective approach for angiofibroma treatment that can be generally applied with the classic CO₂ device.

mTOR-dependent upregulation of xCT blocks melanin synthesis and promotes tumorigenesis

Loss of either TSC1 or TSC2 causes tuberous sclerosis complex (TSC) via activation of mTOR signaling pathway. The two prominent features of TSC are skin lesions including hypomelanic macules and benign tumors in multiple organs, whose molecular alterations are largely unknown. We report here that X_c^- cystine/glutamate antiporter (xCT) was elevated in Tsc2^-/- or Pten^-/- cells, Tsc1 knockout mouse tissues and TSC2-deficient human kidney tumor. xCT was transcriptionally boosted by mTOR-mediated Oct1 signaling cascade. Augmented xCT led to reduction of eumelanin and elevation of pheomelanin in Tsc1 skin knockout mice through mTOR signaling pathway. Disruption of xCT suppressed the proliferation and tumorigenesis of Pten-null cells and Tsc2-null cells. mTOR hyperactive cells were more sensitive to inhibitors of mTOR or xCT. Combined inhibition of mTOR and xCT synergistically blocked the propagation and oncogenesis of mTOR hyperactive cells. Therefore, oncogenic mTOR activation of xCT is a key connection between aberrant melanin synthesis and tumorigenesis. We suggest that xCT is a novel therapeutic target for TSC and other aberrant mTOR-related diseases.

Tuberous sclerosis complex: new insights into clinical and therapeutic approach

Tuberous sclerosis complex (TSC) is a complex disease with many different clinical manifestations. Despite the common opinion that TSC is a rare condition, with a mean incidence of 1/6000 live births and a prevalence of 1/20,000, it is increasingly evident that in reality this is not true. Its clinical sequelae span a range of multiple organ systems, in particular the central nervous system, kidneys, skin and lungs. The management of TSC patients is heavily burdensome in terms of time and healthcare costs both for the families and for the healthcare system. Management options include conservative approaches, surgery, pharmacotherapy with mammalian target of rapamycin inhibitors and recently proposed options such as therapy with anti-EGFR antibody and ultrasound-guided percutaneous microwaves. So far, however, no systematically accepted strategy has been found that is both clinically and economically efficient. Thus, decisions are tailored to patients' characteristics, resource availability and clinical and technical expertise of each single center. This paper reviews the pathophysiology and the clinical (diagnostic-therapeutic) management of TSC.

Short-term safety of mTOR inhibitors in infants and very young children with tuberous sclerosis complex (TSC): Multicentre clinical experience

OBJECTIVE

To evaluate the safety of mTOR inhibitors (sirolimus or everolimus) in infants and very young children with tuberous sclerosis complex (TSC) under two years of age.

METHODS

Study design was retrospective to capture medical record data from 52 international TSC Centres who initiated treatment with sirolimus or everolimus in TSC children before the age of two years. Data collection included demographic and clinical information including reason(s) for initiating treatment with mTOR inhibitors, treatment duration, dosing, and corresponding serum trough levels, response to treatment, and adverse events (AE).

RESULTS

19 of 52 (37%) TSC Centres reported treatment of at least one child with TSC under the age of two years with everolimus or sirolimus. Treatment-related data were provided for 45 patients meeting inclusion criteria. Everolimus was utilised 87% of the time, compared to 24% for sirolimus (5 subjects, 11%, were treated separately with both). Refractory epilepsy (45%) was the most common primary reason for initiating treatment and treatment was initiated on average at 11.6 ± 7.6 months of age. At least one AE, suspected or definitely treatment-related, occurred in 35 of 45 (78%) treated subjects. Most AEs were mild (Grade 1) or moderate (Grade 2) in severity and most commonly related to infections. Severe AE (Grade 3) was reported in 7 subjects (20%) and no life-threatening AE (Grade 4) or death/disability (Grade 5) was reported. Treatment was discontinued due to an AE in 9 of 45 (20%).

CONCLUSIONS

Everolimus, and to a lesser extent sirolimus, are increasingly being used to treat TSC infants and very young children for multiple TSC-associated clinical indications. While AEs were common, most were not severe and did not prevent continued treatment in the majority of this younger population.

Thoracoabdominal imaging of tuberous sclerosis

Imaging of tuberous sclerosis complex has rapidly evolved over the last decade in association with increased understanding of the disease process and new treatment modalities. Tuberous sclerosis complex is best known for the neurological symptoms and the associated neuroimaging findings, and children with tuberous sclerosis complex require active surveillance of associated abnormalities in the chest, abdomen and pelvis. Common findings that require regular imaging surveillance are angiomyolipomas in the kidneys and lymphangioleiomyomatosis in the chest. However multiple rarer associations have been attributed to tuberous sclerosis complex and should be considered by radiologists reviewing any imaging in these children. In this review the authors discuss the spectrum of imaging findings in people with tuberous sclerosis complex, focusing on MR imaging findings in the chest, abdomen and pelvis.

Atypical tuberous sclerosis complex presenting as familial renal cell carcinoma with leiomyomatous stroma

We report an atypical tuberous sclerosis complex (TSC) phenotype presenting as familial multiple renal cell carcinomas (RCCs) with (angio)leiomyomatous stroma (RCCLS) (5/7 familial RCCs) on a background of multiple angiomyolipomas, hypopigmented skin macules, and absence of neurological anomalies. In the index case and three relatives, germline genetic testing identified a heterozygous TSC2 missense pathogenic variant [c.2714 G > A, (p.Arg905Gln)], a rare TSC‐associated alteration which has previously been associated with a milder TSC phenotype. Whole‐exome sequencing of five RCCs from the index case and one RCC from his mother demonstrated either unique tumour‐specific deleterious second hits in TSC2 or significant allelic imbalance at the TSC2 gene locus (5/6 RCCs). This study confirms the key tumourigenic role of tumour‐specific TSC2 second hits in TSC‐associated RCCs and supports the notion that RCCLS may be strongly related to abnormalities of the mTOR pathway.

Nonepithelial Tumors and Tumor-like Lesions of the Skin and Subcutis in Children

This overview of mesenchymal tumors presenting in the skin and/or subcutis in children brings together the range of neoplasms and hamartomas which are seen in this age-group. It is not surprising from the perspective of the pediatric or general surgical pathologist that vascular anomalies, including true neoplasms and vascular malformations, are the common phenotypic category. Since there is considerable morphologic overlap among these lesions, clinicopathologic correlation may be more important than for many of the other mesenchymal tumors. The skin and subcutis are the most common sites of clinical presentation for the infantile myofibroma which is the most common of fibrous mesenchymal tumors in children. Several of the other mesenchymal tumors are more common adults-like dermatofibrosarcoma protuberans, but nonetheless have an important presence in children, even as a congenital neoplasm. A lipomatous tumor in a young child should be considered as a possible manifestation of an overgrowth syndrome.

Fibrous cephalic plaques in tuberous sclerosis complex

BACKGROUND

Fibrous cephalic plaques (FCPs) stereotypically develop on the forehead of patients with tuberous sclerosis complex (TSC). They constitute a major feature for TSC diagnosis and may present before other TSC-related cutaneous hamartomas.

OBJECTIVE

To describe the clinical characteristics of FCPs in TSC.

METHODS

A total of 113 patients with TSC were enrolled in an observational cohort study. Retrospective analysis of medical records and skin photography was performed. FCPs were categorized by anatomic location and size.

RESULTS

FCPs were observed in 36% of patients (41 of 113). Of 62 total lesions, 58% were 1 to less than 5 cm, 13% were 5 cm or larger, and 29% were of unknown size mostly because of prior excision. The distribution of lesions was 39% on the forehead, 27% on the face (nonforehead), 3% on the neck, and 31% on the scalp. Fourteen patients had similar lesions less than 1 cm in diameter. Histopathologically, FCPs displayed dermal collagenosis, decreased elastic fibers, and features of angiofibromas or fibrofolliculomas.

LIMITATIONS

Men were under-represented because the cohort was enriched for patients with TSC with lymphangioleiomyomatosis, which occurs in adult women.

CONCLUSION

Two-fifths of FCPs presented on the forehead, with most of the remainder in other locations on the face and scalp. Better recognition of these lesions may lead to earlier diagnosis of TSC.

Hereditary Renal Cystic Disorders: Imaging of the Kidneys and Beyond

The purpose of this article is to review the hereditary renal cystic diseases that can manifest in children and adults, with specific attention to pathogenesis and imaging features. Various common and uncommon hereditary renal cystic diseases are reviewed in terms of their underlying etiology, including the involved genetic mutations and the affected proteins and cellular structures. Focus is placed on the morphologic findings in each condition and the features that distinguish one disorder from another. The two most common categories of hereditary renal cystic disease are (a) the ciliopathic disorders, which are related to mutations affecting the primary cilia (called "ciliopathies"), and (b) the phakomatoses. Autosomal dominant polycystic kidney disease, autosomal recessive polycystic kidney disease, and the "medullary cystic disease complex" are all ciliopathies but have different phenotypes. Tuberous sclerosis complex and the associated "contiguous gene syndrome," as well as von Hippel-Lindau syndrome, are phakomatoses that can manifest with cystic renal lesions but have uniquely different extrarenal manifestations. Finally, DICER1 mutations can manifest with renal cystic lesions (typically, cystic nephromas) in patients predisposed to other malignancies in the chest, ovaries, and thyroid. Although some overlap exists in the appearance of the renal cysts associated with each of these diseases, there are clear morphologic differences (eg, cyst size, location, and complexity) that are emphasized in this review. To improve patient outcomes, it is important for the radiologist to recognize the various hereditary renal cystic diseases so that a correct diagnosis is assigned and so that the patient is adequately evaluated and followed up. ^©RSNA, 2017.

Cutaneous manifestations of tuberous sclerosis complex and the paediatrician's role

Tuberous sclerosis complex (TSC) is a multisystem genetic disorder stemming from unregulated activation of the mammalian target of rapamycin (mTOR) pathway, resulting in the growth of hamartomas in multiple organs. TSC-related skin lesions often develop early in life and can be disfiguring, emotionally distressful and even painful at times. Recognition of TSC-associated skin features by paediatricians can be a catalyst for facilitating early implementation of treatment strategies and establishing appropriate follow-up care. The range of potential treatment options for symptomatic or disfiguring TSC-associated skin lesions includes non-pharmacological (surgical excision, laser therapy) and pharmacological (eg, topical or systemic mTOR inhibitors) alternatives. In this review, we discuss the relevance of TSC-associated skin findings, highlight available treatment options, review guideline recommendations and emphasise the role of the primary care physician in the management of this complex disease.

Clinical Characteristics of Connective Tissue Nevi in Tuberous Sclerosis Complex With Special Emphasis on Shagreen Patches

Importance

Patients with tuberous sclerosis complex (TSC) frequently develop collagenous connective tissue nevi. The prototypical lesion is a large shagreen patch located on the lower back, but some patients only manifest small collagenomas or have lesions elsewhere on the body. The ability to recognize these variable presentations can be important for the diagnosis of TSC.

Objective

To describe the clinical characteristics of connective tissue nevi on the trunk and extremities of patients with tuberous sclerosis complex.

Design, Setting, and Participants

A retrospective analysis of patient medical records and skin photography was performed; 104 adult patients with TSC were enrolled in an observational cohort study that was enriched for those with pulmonary lymphangioleiomyomatosis, and was therefore composed mostly of women (99 women, 5 men). All patients included were examined at the National Institutes of Health (NIH) in Bethesda, Maryland, from 1998 to 2013. Connective tissue nevi were categorized per anatomic location and size. Lesions less than 1 cm in diameter were termed collagenomas. Shagreen patches were characterized as small (1 to <4 cm), medium (4 to <8 cm), and large (≥8 cm).

Main Outcome and Measures

Frequency, anatomic location, size, and histological appearance of connective tissue nevi in patients with TSC.

Results

Overall, 58 of 104 patients (median [range] age, 42 [19-70] years) with TSC (56%) had at least 1 connective tissue nevus on the trunk or thighs; of these, 28 of 58 patients (48%) had a solitary lesion, and 30 of 58 patients (52%) had 2 or more lesions. Overall, 120 lesions from 55 patients were classified by size; 46 lesions (38%) were collagenomas; 39 lesions (32%) were small shagreen patches; 21 lesions (18%), medium shagreen patches; and 14 lesions (12%), large shagreen patches. The distribution of lesions was 9% (n = 11), upper back; 29% (n = 35), middle back; 51% (n = 61), lower back; and 11% (n = 13), other locations. All 26 shagreen patches that were analyzed histopathologically had coarse collagen fibers and 24 of 26 stained with Miller elastic stain had decreased elastic fibers. On immunoblot analysis, fibroblasts grown from shagreen patches expressed higher levels of phosphorylated ribosomal protein S6 than paired fibroblasts from normal-appearing skin.

Conclusions and Relevance

Tuberous sclerosis complex-related connective tissue nevi are not limited to the lower back, and occasionally present on the central or upper back, buttocks, or thighs. Elastic fibers are typically decreased. Recognition of these variable presentations can be important for TSC diagnosis.

Dermatological manifestations of tuberous sclerosis complex (TSC)

Tuberous sclerosis complex (TSC) is a genetic multisystem disorder with prominent skin involvement that frequently occurs in early childhood. Dermatologic manifestations include facial angiofibromas, hypomelanotic macules, fibrous cephalic plaques, shagreen patches, and ungual fibromas. The International TSC Consensus Conference in 2012 provided guidelines for standardized baseline evaluation and follow-up. Detailed clinical dermatological evaluation at the time of diagnosis and annual skin examination is recommended for both pediatric and adult populations. The onset of dermatological manifestations is clearly age-related. However, dermatologists also have to assess for clinical manifestations beyond their own specialty. With advances in genetics and the advent of mTORC1 inhibitors, new specific therapeutic options have become available for TSC patients with skin manifestations. Early intervention is commonly recommended for symptomatic, rapidly evolving, disfiguring, or debilitating lesions. The consensus guidelines recommend "treatment as appropriate for the lesion and clinical context" and suggest the use of surgical excision, laser therapy, or topical mTORC1 inhibitors. Topical mTORC1 inhibitors present a useful option for TSC-associated skin lesions, particularly in medically complex patients. They may prevent or reduce the risks of subsequent surgeries and permanent scarring.

Long-term treatment of cutaneous manifestations of tuberous sclerosis complex with topical 1% sirolimus cream: A prospective study of 25 patients

BACKGROUND

Data on long-term topical sirolimus treatment of the cutaneous manifestations of tuberous sclerosis complex are rare.

OBJECTIVE

To evaluate the long-term benefit and tolerance of topical 1% sirolimus in tuberous sclerosis complex.

METHODS

In this 18-month prospective single-center study, 1% sirolimus cream was applied daily to facial angiofibromas (FAs), fibrous cephalic plaques (FCPs), shagreen patches, hypomelanotic macules, and ungual fibromas. After complete clearance (CC) of FAs, we evaluated a maintenance protocol of 3 applications weekly.

RESULTS

Twenty-five patients were enrolled. Fifty percent obtained CC of FAs within 9 months. Of 7 patients with CC (58%) who were following the maintenance protocol, 6 relapsed within 7 months and 1 was still responding at 1 year. Of 16 patients with FCPs, 7 (44%) remained stable at 12 months and 9 (56%) improved after 3 to 9 months of treatment. Only 1 of 5 patients treated for shagreen patches showed improvement at 12 months. Treatment was well tolerated with no serious adverse events.

LIMITATIONS

The small number of patients was a limitation.

CONCLUSIONS

Topical 1% sirolimus applied daily produced positive responses in treatment of FAs, FCPs, and facial hypomelanotic macules and was well tolerated. A 3-times-weekly maintenance protocol did not prevent FA relapses.