Imaging Manifestations of a Subependymal Giant Cell Astrocytoma in Tuberous Sclerosis

Imaging of supratentorial intraventricular masses in children: a pictorial review-part 2

PURPOSE

This article is the second in a two-part series aimed at exploring the spectrum of supratentorial intraventricular masses in children. In particular, this part delves into masses originating from cells of the ventricular lining, those within the septum pellucidum, and brain parenchyma cells extending into the ventricles. The aim of this series is to offer a comprehensive understanding of these supratentorial intraventricular masses, encompassing their primary clinical findings and histological definitions.

METHODS

We conducted a review and analysis of relevant epidemiological data, the current genetics/molecular classifications as per the fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (WHO CNS5), and imaging findings. Each supratentorial intraventricular mass was individually evaluated, with a detailed discussion on its clinical and histological features.

RESULTS

This article covers a range of supratentorial intraventricular masses observed in children. These include colloid cysts, subependymal giant cell astrocytomas, ependymomas, gangliogliomas, myxoid glioneuronal tumors, central neurocytomas, high-grade gliomas, pilocytic astrocytomas, cavernous malformations, and other embryonal tumors. Each mass type is characterized both clinically and histologically, offering an in-depth review of their individual imaging characteristics.

CONCLUSION

The WHO CNS5 introduces notable changes, emphasizing the vital importance of molecular diagnostics in classifying pediatric central nervous system tumors. These foundational shifts have significant potential to impact management strategies and, as a result, the outcomes of intraventricular masses in children.

Sporadic subependymal giant cell astrocytoma with somatic TSC2 mutation: A case report

Subependymal giant cell astrocytoma (SEGA) is a rare circumscribed astrocytic glioma that occurs in approximately 25% of all tuberous sclerosis (TSC) cases. Herein, we discuss an atypical presentation of SEGA, including the genetic alterations, impact on clinical presentation, and the determinants of each medical and surgical treatment option. A 14-year-old girl presented with intermittent headache and a right intraventricular mass originating near the foramen of Monro. The tumor's proximity to critical structures necessitated maximum safe resection, which improved her symptoms. Histological findings indicated SEGA, and genetic sequencing revealed a TSC2 mutation. However, complete clinical and radiological evaluations failed to reveal TSC. Two months later, a new subependymal nodule was incidentally found. She had a recurrent left occipital horn lesion and diffuse smooth leptomeningeal enhancement with no spine drop metastases. She was administered everolimus as the tumor was considered unresectable. Subsequent imaging revealed a reduction in both residual and new lesions.

Radiohistogenomics of pediatric low-grade neuroepithelial tumors

PURPOSE

In addition to histology, genetic alteration is now required to classify many central nervous system (CNS) tumors according to the most recent World Health Organization CNS tumor classification scheme. Although that is still not the case for classifying pediatric low-grade neuroepithelial tumors (PLGNTs), genetic and molecular features are increasingly being used for making treatment decisions. This approach has become a standard clinical practice in many specialized pediatric cancer centers and will likely be more widely practiced in the near future. This paradigm shift in the management of PLGNTs necessitates better understanding of how genetic alterations influence histology and imaging characteristics of individual PLGNT phenotypes.

METHODS

The complex association of genetic alterations with histology, clinical, and imaging of each phenotype of the extremely heterogeneous PLGNT family has been addressed in a holistic approach in this up-to-date review article. A new imaging stratification scheme has been proposed based on tumor morphology, location, histology, and genetics. Imaging characteristics of each PLGNT entity are also depicted in light of histology and genetics.

CONCLUSION

This article reviews the association of specific genetic alteration with location, histology, imaging, and prognosis of a specific tumor of the PLGNT family and how that information can be used for better imaging of these tumors.

Bilateral Renal Angiomyolipomas and Subependymal Giant Cell Astrocytoma Associated with Tuberous Sclerosis Complex: a Case Report and Review of The Literature

Tuberous sclerosis complex (TSC) is an autosomal-dominant multi system disorder. The genetic basis of the disorder is mutations in the TSC1 or TSC2 gene, which leads to over activation of the mammalian target of rapamycin (mTOR) protein complex and results in development of benign tumors in different body systems such as brain, skin, lungs and kidney. The mTOR inhibitors are presently the main treatment option for patients with TSC. We here report a 21-year female patient with large bilateral angiomyolipoma (AML) in both kidneys with longest diameter more than 12.3 cm and subependymal giant cell astrocytoma (SEGA). Treatment with everolimus (EVE) was initiated at a dose of 10.0 mg/day and continued during the following 3 years. Magnetic resonance imaging (MRI) was performed before treatment with everolimus was initiated, and consequently at 12 and 36 months for follow-up of the efficacy of the treatment. After 3 years, the total size of largest AML decreased by ~24.0% in the longest diameter. A reduction of the total size of SEGA was also observed. The most common adverse effect of treatment was stomatitis grades 3 to 4 and one febrile episode associated with skin rash that required a reduced dose of EVE. In conclusion, the everolimus treatment improved even such a large renal AML and the effect persisted during the long-term administration with a small number of adverse effects. A positive effect was observed on the brain tumor as well.