Cross-sectional Imaging Review of Tuberous Sclerosis

Multisystem diseases in the abdomen and pelvis: imaging manifestations and diagnostic roles of cross-sectional imaging

Systemic diseases, such as IgG4-related disease, sarcoidosis, and amyloidosis, usually involve multiple systems or organs simultaneously or sequentially. The gastrointestinal tract, hepatobiliary system, and genitourinary tract are commonly involved in many multisystem diseases and can also be the first sites with disease involvement. Cross-sectional imaging, such as CT and MR, plays an important role in the diagnosis and management of multisystem diseases by aiding in the evaluation of multiorgan involvement. Here, common imaging features of frequently affected organs are reviewed in multisystem diseases that we often encounter in the abdomen and pelvis, and the diagnostic roles of cross-sectional imaging for these diseases are also discussed.

Genetic syndromes associated with pancreatic neuroendocrine neoplasms and imaging diagnostic strategies

Pancreatic neuroendocrine neoplasms (pNENs) are the second most common pancreatic malignancy. While most cases are sporadic, a small proportion is associated with genetic syndromes, such as Multiple Endocrine Neoplasia (MEN), Von Hippel-Lindau Syndrome (VHL), Neurofibromatosis Type 1 (NF1), and Tuberous Sclerosis Complex (TSC). This review aims to use pNENs as a clue to reveal the full spectrum of disease, providing a comprehensive understanding of diagnosis. It aids in promptly identifying abnormalities in other organs, recognizing familial genetic mutations, and achieving personalized treatment.

Long-term volume reduction in renal angiomyolipomas embolized by gelatin sponge particles with or without supplementary microcoil embolization

OBJECTIVE

To examine the effect of supplementary microcoil embolization on the long-term progression of angiomyolipomas embolized using gelatin sponge particles (GSPs).

METHODS

This retrospective study included 29 unruptured angiomyolipomas in 25 patients, treated by complete embolization and radiological follow-up for ≥3 years. Embolization was performed using GSPs and supplementary microcoils. Supplementary microcoil embolization affecting >90% of the tumor vasculature was defined as microcoil embolization. Tumor volumes pre- and post-embolization were measured by computed tomography or magnetic resonance imaging.

RESULTS

Eleven tumors received supplementary microcoil embolization and 18 tumors did not. Relative tumor reduction at >3 years post-embolization was significantly greater in tumors with supplementary microcoil embolization compared with tumors without microcoil embolization (81% ± 8% vs. 55% ± 29%). Fourteen tumors tended to show volume regrowth and the volumes of the remaining 15 tumors continued to decline. Tumors without supplementary microcoil embolization were more likely to show volume regrowth during follow-up than tumors with supplementary microcoil embolization (78% vs. 0%, respectively).

CONCLUSIONS

When using a combination of GSPs and microcoils, supplementary microcoil embolization should be carried out to ensure maximum long-term reduction in tumor volume in patients with angiomyolipomas.

Imaging More than Skin-Deep: Radiologic and Dermatologic Presentations of Systemic Disorders

Background: Cutaneous manifestations of systemic diseases are diverse and sometimes precede more serious diseases and symptomatology. Similarly, radiologic imaging plays a key role in early diagnosis and determination of the extent of systemic involvement. Simultaneous awareness of skin and imaging manifestations can help the radiologist to narrow down differential diagnosis even if imaging findings are nonspecific. Aims: To improve diagnostic accuracy and patient care, it is important that clinicians and radiologists be familiar with both cutaneous and radiologic features of various systemic disorders. This article reviews cutaneous manifestations and imaging findings of commonly encountered systemic diseases. Conclusions: Familiarity with the most disease-specific skin lesions help the radiologist pinpoint a specific diagnosis and consequently, in preventing unnecessary invasive workups and contributing to improved patient care.

TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.

A solitary extraventricular subependymal giant cell astrocytoma in the absence of tuberous sclerosis

Subependymal giant cell astrocytomas (SEGAs) are the most common intracranial tumors in Tuberous Sclerosis Complex (TSC). Very few cases of solitary SEGA without a diagnosis of TSC have been described. Most of these previously reported solitary SEGAs were located near the caudothalamic groove or in close proximity to the lateral ventricles. Here, we describe a unique case of solitary extraventricular SEGA in a 17-year-old boy who presented with new-onset seizures in the absence of the clinical and genetic diagnosis of TSC. This extraventricular SEGA was involving white matter and cortex of the occipital lobe and was predominantly hypointense on T1 and T2-weighted images with a markedly hypointense signal on susceptibility-weighted images likely secondary to dense internal calcifications. Solitary SEGA can occur in the extraventricular location in patients without TSC and should be included in the differential diagnosis of a densely calcified supratentorial intra-axial tumor in children, especially during the second decade of life.

Can we predict the existence of extrarenal feeders to renal angiomyolipomas?

OBJECTIVES

To identify factors predicting the presence of extrarenal feeders to renal angiomyolipomas (AMLs) METHODS: This is a retrospective study of 44 patients with 58 renal AMLs embolized in our department. Arteriography obtained during embolization and CT angiography obtained before and after embolization were reviewed to characterize AMLs with and without extrarenal feeders. Tumor characteristics were compared between the two groups. Simple logistic regression and ROC curve analysis were performed. P < 0.05 was considered to be statistically significant.

RESULTS

Of the 58 AMLs reviewed, 29% had extrarenal arteries and 71% did not. AMLs with extrarenal feeders were significantly larger than those without, in terms of volume (median, 368 mL versus 109 mL, p < 0.0002) and the largest diameter (mean, 12.0 cm versus 7.7 cm, p < 0.0001). Patient age, presence of tuberous sclerosis complex or sporadic lymphangioleiomyomatosis, and tumor location did not differ between the groups. The largest diameter and volume had similar predictive values for the presence of extrarenal feeders (AUC, 0.83 versus 0.82, p = 0.673). Extrarenal feeders were present in 0%, 21%, and 79% of the AMLs ≤ 6.5 cm, AMLs 6.6-10.5 cm, and AMLs > 10.5 cm, respectively.

CONCLUSIONS

AML size correlates with the presence of extrarenal feeders, with the largest diameter and volume being significant predictors. AMLs > 10.5 cm had a high chance of extrarenal feeders, making it mandatory to search for feeders to them in order to avoid incomplete embolization; AMLs ≤ 6.5 cm did not have extrarenal feeders, making a search for them unnecessary in these cases.

KEY POINTS

• The presence of extrarenal feeders to renal angiomyolipoma is associated with tumor size, but not with patient age, concomitant disease, or tumor location. • The largest diameter and volume predict the presence of extrarenal feeders to AML, with similar predictive values. • AMLs > 10.5 cm have a high chance (79%) of extrarenal feeders, making it mandatory to search for feeders to them in order to avoid incomplete embolization; AMLs ≤ 6.5 cm do not have extrarenal feeders, making a search for them unnecessary in these cases.

Comorbidities of Rare Epilepsies: Results from the Rare Epilepsy Network

OBJECTIVE

To describe the prevalence and characteristics of comorbidities in persons with rare epilepsies.

STUDY DESIGN

Persons with rare epilepsies and caregivers of those affected were recruited through the Epilepsy Foundation and more than 30 rare epilepsy advocacy organizations affiliated with the Rare Epilepsy Network (REN). A web-based survey was conducted using a questionnaire consisting of core sections to collect data from affected persons on various aspects, including comorbidities. Comorbidity information was grouped into 15 classes, 12 of which had a stem question followed by detailed branch questions and 3 that were created from a combination of related questions.

RESULTS

Of 795 persons with more than 30 different rare epilepsy diagnosis groups, one-half had ≥5 comorbidity classes and 97% were classified as complex chronic disease (C-CD). The highest number of comorbidity classes reported per person were persons with Aicardi syndrome, Phelan-McDermid syndrome (median, 7.0; IQR, 5.0-9.0), and tuberous sclerosis complex (median, 6.0; IQR, 4.0-8.0). The most common comorbidity classes were learning/developmental disability (71%), mental health issues (71%), sleep disorders (60%), brain abnormalities (52%), oral issues (49%), bone-joint issues (42%), hyper/hypotonia (42%), and eye-vision disorders (38%). The prevalence of brain abnormalities, hyper/hypotonia, eye, and cardiac disorders was significantly higher in persons first diagnosed with epilepsy at a younger age (<9 months) than in those first diagnosed at an older age (P < .05 for trend).

CONCLUSIONS

Nearly all persons with rare epilepsies are medically complex, with a high prevalence of multiple comorbidities, especially those who were diagnosed with epilepsy in the first year of life. Comorbidities should be carefully considered in the diagnosis and management of persons with rare epilepsies.

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.

Central nervous system manifestations of tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a neurocutaneous autosomal-dominant genetic syndrome marked by development of hamartomatous lesions arising from dysfunction of the mammalian target of rapamycin (mTOR) pathway. Although TSC remains a heterogeneous clinical entity, the recent inclusion of genetic diagnostic criteria reflects advancement in our understanding of its underlying etiopathogenesis. Abnormal cellular growth, differentiation, and migration result in multisystem sequelae, with neurologic manifestations of TSC representing the primary cause of morbidity and mortality for the majority of individuals. Modern imaging techniques aid in the diagnosis of TSC and guide treatment strategies by revealing central nervous system findings. Cortical tubers are the namesake lesion of the disorder and occur in up to 90% of cases, often exerting significant epileptogenic potential. Subependymal nodules are found in 80% of patients as calcified tumors lining the ependyma of the lateral ventricles. In some cases, these nodules are thought to progress to subependymal giant cell astrocytomas and may present with obstructive hydrocephalus. Retinal astrocytic hamartomas are also common, present in 50% of patients. Surgery remains the treatment of choice for large or symptomatic lesions, though clinical trials have highlighted a potential role for mTOR pathway antagonism. A multidisciplinary approach is necessary for achieving optimal patient outcomes.

Postembolization Intratumoral Chronic Bleeding, without the Classic CT Feature of Active Extravasation, in Tuberous Sclerosis Complex-Related Renal Angiomyolipoma: Two Case Reports

Two patients with tuberous sclerosis complex each had multiple bilateral renal angiomyolipomas. After undergoing embolization for a ruptured angiomyolipoma, patient 1 experienced long-lasting abdominal fullness; contrast-enhanced computed tomography (CECT) revealed a large chronic hematoma without contrast extravasation. Patient 2 underwent embolization for the largest right renal angiomyolipoma which contained a chronic hematoma. 2 weeks later, the symptom of abdominal fullness presented, and CECT revealed that the preexisting hematoma had enlarged without contrast extravasation. In both cases, a second embolization of the angiomyolipomas resulted in shrinking of the intratumoral hematomas and alleviation of the associated symptoms. Therefore, chronic postembolization intratumoral bleeding from renal angiomyolipoma may present as a persistently large or growing hematoma with an associated symptom of abdominal fullness but without the typical CECT feature of active extravasation.

Neuroimaging Features of Tuberous Sclerosis Complex and Chiari Type I Malformation: A Rare Association

An 8-year-old girl was admitted during the night in our emergency department for an acute episode of seizures. The patient underwent computed-tomography (CT) brain scan (Toshiba ® Aquilion 64-TSX-101A/HC) and magnetic resonance imaging (MRI) brain scan (Philips® Achieva 1.5T). CT scan showed left frontal calcified nodules and calcified periventricular subependymal nodules. Subsequently, MRI evaluation revealed cortical and subcortical nodules that showed low signal with respect to the white matter on T1-weighted imaging sequences and high signal both in T2-weighted imaging sequences and in fluid-attenuated inversion recovery sequences. We also showed a herniation of cerebellar tonsils through the foramen magnum (Chiari malformation Type I [CMI]) with the associated hydrosyringomyelic cavity. Our report showed a rare association between tuberous sclerosis complex and CMI.

Dysplasia and overgrowth: magnetic resonance imaging of pediatric brain abnormalities secondary to alterations in the mechanistic target of rapamycin pathway

The current classification of malformations of cortical development is based on the type of disrupted embryological process (cell proliferation, migration, or cortical organization/post-migrational development) and the resulting morphological anomalous pattern of findings. An ideal classification would include knowledge of biological pathways. It has recently been demonstrated that alterations affecting the mechanistic target of rapamycin (mTOR) signaling pathway result in diverse abnormalities such as dysplastic megalencephaly, hemimegalencephaly, ganglioglioma, dysplastic cerebellar gangliocytoma, focal cortical dysplasia type IIb, and brain lesions associated with tuberous sclerosis. We review the neuroimaging findings in brain abnormalities related to alterations in the mTOR pathway, following the emerging trend from morphology towards genetics in the classification of malformations of cortical development. This approach improves the understanding of anomalous brain development and allows precise diagnosis and potentially targeted therapies that may regulate mTOR pathway function.

Imaging and Screening of Hereditary Cancer Syndromes

There is a wide spectrum of mendelian disorders that predispose patients to an increased risk of benign as well as malignant tumors. Hereditary cancer syndromes are characterized by the early onset of diverse, frequently advanced malignancies in specific organ systems in multiple family members, posing significant challenges to diagnosis and management. A better understanding of the genetic abnormalities and pathophysiology that underlie these disorders has led to contemporary paradigms to screen, allowing early diagnosis, and has improved targeted therapies to aid in management. This article reviews select hereditary cancer syndromes with an emphasis on imaging-based screening and surveillance strategies.