Neurosurgical treatment of tuberous sclerosis complex lesions

Qualitative and quantitative evaluation for the heterogeneity of cortical tubers using structural imaging and diffusion-weighted imaging to predict the epileptogenicity in tuberous sclerosis complex patients

PURPOSE

We aimed to evaluate whether the heterogeneity of tuber imaging features, evaluated on the structural imaging and apparent diffusion coefficient (ADC) map, can facilitate detecting epileptogenic tubers before surgery in tuberous sclerosis complex (TSC) patients.

METHODS

Twenty-three consecutive patients, who underwent tuber resection at our institute, were retrospectively selected. A total of 125 tubers (39 epileptogenic, 86 non-epileptogenic) were used for the analysis. Tuber heterogeneity was evaluated, using a 5-point visual scale and standard deviation of ADC values (ADC_sd). A 5-point visual scale reflected the degree of T1/T2 prolongation, presence of internal cystic degeneration, and their spatial distribution within the tuber. These results were statistically compared between epileptogenic and non-epileptogenic groups, and their performance in predicting the epileptogenicity was also evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

A 5-point visual scale demonstrated that more heterogeneous tubers were significantly more epileptogenic (p < 0.001). Multiplicity of internal cystic degeneration moderately correlated with epileptogenicity (p < 0.03) based on the comparison between class 4 and class 5 tubers. ADC_sd was significantly higher in epileptogenic tubers (p < 0.001). ROC curves revealed that a 5-point visual scale demonstrated higher area under the curve (AUC) value than ADC_sd (0.75 and 0.72, respectively).

CONCLUSION

Tuber heterogeneity may help identify the epileptogenic tubers in presurgical TSC patients. Visual assessment and standard deviation of ADC value, which are easier to implement in clinical use, may be a useful tool predicting epileptogenic tubers, improving presurgical clinical management for TSC patients with intractable epilepsy.

Expression and cellular distribution of FGF13 in cortical tubers of the tuberous sclerosis complex

Cortical tubers in patients with tuberous sclerosis complex (TSC) are highly associated with intractable epilepsy. Recent evidence suggests a close relationship between FGF13 and seizures. To understand the role of FGF13 in the pathogenesis of cortical tubers, we investigated the expression pattern of FGF13 in cortical tubers of TSC compared with normal control cortices (CTX). We found that both the mRNA and protein levels of FGF13 were significantly higher in the cortical tubers from patients with TSC than in the control cortices. The immunohistochemical results showed strong FGF13 immunoreactivity in abnormal cells, including dysplastic neurons (DNs) and giant cells (GCs). Moreover, double-label immunofluorescence analyses confirmed that FGF13 was mainly localized in neurons and nearly absent in glia-like cells. The protein levels of FGF13 in the TSC samples were positively correlated with the frequency of seizures before surgery. Taken together, these results suggest that the overexpression and distribution pattern of FGF13 may be related to intractable epilepsy caused by TSC.

Neurosurgical treatment of subependymal giant cell astrocytomas in tuberous sclerosis complex: a series of 44 surgical procedures in 31 patients

BACKGROUND

Subependymal giant cell astrocytomas (SEGA) are benign tumors characteristic of tuberous sclerosis complex (TSC) that may cause hydrocephalus. Various treatments are nowadays available as mTOR inhibitors or surgery. Surgery is still a valid option especially for symptomatic and larger tumors.

METHODS

From January 1994 to December 2015, 31 TSC patients harboring SEGA underwent surgery at the Department of Neurosurgery of the Meyer Pediatric Hospital, Florence. Indications for surgery were tumor size and location, growth and cystization/hemorrhage, and hydrocephalus. Clinical data, preoperative and postoperative MRI, recurrence rate, further surgical procedures, and related complications were analyzed.

RESULTS

A total of 44 surgeries were performed in 31 TSC patients affected by SEGA, achieving gross total removal (GTR) and subtotal removal (STR), respectively, in 36 and 8 patients. Recurrences occurred in 11 patients; 9 of them underwent further surgical procedures and 2 were treated with mTOR pathway inhibitors. Surgical morbidity and mortality were, respectively, 22.7% and 2.3%. After a mean follow-up of 4.9 years, 90% of patients were tumor-free with good neurological status in 93.3%; twelve (40%) had a ventriculo-peritoneal shunt (VPS) for hydrocephalus.

CONCLUSIONS

The present series confirms that the surgical approach, combined with mTOR inhibitors, is still a valid option for the treatment of SEGAs.

Impact on Clinical Decision Making of Next-Generation Sequencing in Pediatric Epilepsy in a Tertiary Epilepsy Referral Center

Background. Next-generation sequencing (NGS) describes new powerful techniques of nucleic acid analysis, which allow not only disease gene identification diagnostics but also applications for transcriptome/methylation analysis and meta-genomics. NGS helps identify many monogenic epilepsy syndromes. Pediatric epilepsy patients can be tested using NGS epilepsy panels to diagnose them, thereby influencing treatment choices. The primary objective of this study was to evaluate the impact of genetic testing on clinical decision making in pediatric epilepsy patients. Methods. We completed a single-center retrospective cohort study of 91 patients (43 male) aged 19 years or less undergoing NGS with epilepsy panels differing in size ranging from 5 to 434 genes from October 2013 to September 2017. Results. During a mean time of 3.6 years between symptom onset and genetic testing, subjects most frequently showed epileptic encephalopathy (40%), focal epilepsy (33%), and generalized epilepsy (18%). In 16 patients (18% of the study population), "pathogenic" or "likely pathogenic" results according to ACMG criteria were found. Ten of the 16 patients (63%) experienced changes in clinical management regarding their medication and avoidance of further diagnostic evaluation, that is, presurgical evaluation. Conclusion. NGS epilepsy panels contribute to the diagnosis of pediatric epilepsy patients and may change their clinical management with regard to both preventing unnecessary and potentially harmful diagnostic procedures and management. Thus, the present data support the early implementation in order to adopt clinical management in selected cases and prevent further invasive investigations. Given the relatively small sample size and heterogeneous panels a larger prospective study with more homogeneous panels would be helpful to further determine the impact of NGS on clinical decision making.

Rapamycin therapy for neonatal tuberous sclerosis complex with cardiac rhabdomyomas: A case report and review

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease that varies greatly in its expression. The current study reports a novel case of TSC caused by a TSC2 mutation (TSC2c.1642_1643insA or TSC2p.K549fsX589), in which multiple cardiac rhabdomyomas were detected by fetal echocardiography in week 31 of pregnancy. The infant was delivered successfully; however, seizures began 16 days following birth. Subsequent genetic tests confirmed a diagnosis of TSC. Rapamycin treatment resulted in regression of cardiac rhabdomyomas and controlled seizures. The current study demonstrates the value of fetal echocardiography in the diagnosis of TSC and suggests that inhibition of the mammalian target of the rapamycin (mTOR) signaling pathway may be considered as a potential antiepileptogenic therapy for neonatal TSC. In addition, it was demonstrated that rapamycin treatment was therapeutically beneficial for preventing disorders caused by abnormal mTOR signaling, such as cancer. According to the literature, cardiac rhabdomyomas, seizures and skin lesions are well established markers for TSC in neonates. MRI scans of the brain and genetic screening of TSC1 and TSC2 genes may facilitate an early diagnosis of TSC.

Tuberous sclerosis complex: the past and the future

Renal lesions represent the second most significant cause of morbidity and mortality in patients with tuberous sclerosis complex (TSC). Recent advances in the understanding of the pathophysiology of TSC have led to the exploration of new potential therapeutic targets. Clinical trials with mammalian target of rapamycin (mTOR) inhibitors have demonstrated promising results for several indications, such as renal angiomyolipoma, subependymal giant cell astrocytoma, lymphangioleiomyomatosis and facial angiofibromas. Currently, there is a scarcity of natural history data and randomized, placebo-controlled clinical trials on TSC. Recently, however, recommendations for the diagnostic criteria, surveillance, and management of TSC patients have been updated. This review focuses on these novel recommendations and highlights the need for multidisciplinary follow-up of this multi-systemic disease.

Surgical treatment of subependymal giant cell astrocytoma in tuberous sclerosis complex patients

BACKGROUND

Subependymal giant cell astrocytoma is a brain tumor associated with tuberous sclerosis complex. There are two treatment options for subependymal giant cell astrocytomas: surgery or mammalian target of rapamycin inhibitor. The analysis of outcome of subependymal giant cell astrocytoma surgery may help characterize the patients who may benefit from pharmacotherapy.

METHODS

Sixty-four subependymal giant cell astrocytoma surgeries in 57 tuberous sclerosis complex patients with at least a 12-month follow-up were included in the study. The tumor size, age of the patients, mutation in the TSC1 or TSC2 gene, indication for the surgery, and postsurgical complications were analyzed.

RESULTS

The mean age of patients at surgery was 9.7 years. Mean follow-up after surgery was 63.7 months. Thirty-seven (57.8%) tumors were symptomatic and 27 (42.2%) were asymptomatic. Patients with TSC2 mutations developed subependymal giant cell astrocytoma at a significantly younger age than individuals with TSC1 mutations. Four patients (6.2% of all surgeries) died after surgery. Surgery-related complications were reported in 0%, 46%, 83%, 81%, and 67% of patients with tumors <2 cm, between 2 and 3 cm, between 3 and 4 cm, >4 cm, and bilateral subependymal giant cell astrocytomas, respectively, and were most common in children younger than 3 years of age. The most common complications included hemiparesis, hydrocephalus, hematoma, and cognitive decline.

CONCLUSIONS

Our study indicates that subependymal giant cell astrocytoma surgery is associated with significant risk in individuals with bilateral subependymal giant cell astrocytomas, tumors bigger than 2 cm, and in children younger than 3 years of age. Therefore, tuberous sclerosis complex patients should be thoroughly screened for subependymal giant cell astrocytoma growth, and early treatment should be considered in selected patients.

Congenital subependymal giant cell astrocytomas in patients with tuberous sclerosis complex

PURPOSE

Subependymal giant cell astrocytoma (SEGA) is a brain tumor associated with tuberous sclerosis complex (TSC). It usually grows in a second decade of life, but may develop in the first months of life. The aim of this work was to establish the incidence, clinical features, and outcome of congenital SEGA in TSC patients.

METHODS

Cohort of 452 TSC patients was reviewed to identify cases with growing or hydrocephalus producing SEGAs in the first 3 months of life. Clinical presentation, size of the tumor, growth rate, mutational analysis, treatment applied, and outcome were analyzed.

RESULTS

Ten (2.2 %) patients presented with SEGA in the first 3 months of life. All of them had documented SEGA growth and all developed hydrocephalus. In eight patients, mutational analysis was done, and in all of them, TSC2 gene mutations were identified. Mean maximum SEGA diameter at baseline was 21.8 mm. Mean SEGA growth rate observed postnatally was 2.78 mm per month and tended to be higher (5.43 mm per month) in patients with TSC2/PKD1 mutation than in other cases. Seven patients underwent SEGA surgery and surgery-related complications were observed in 57.1 % cases. One patient was successfully treated with everolimus as a primary treatment.

CONCLUSIONS

Congenital SEGA develops 2.2 % of TSC patients. Patients with TSC2 mutations, and especially with TSC2/PKD1 mutations, are more prone to develop SEGA earlier in childhood and should be screened for SEGA from birth. In young infants with SEGA, both surgery and mTOR inhibitor should be considered as a treatment option.

Resection of subependymal giant cell astrocytoma guided by intraoperative magnetic resonance imaging and neuronavigation

PURPOSE

Subependymal giant cell astrocytoma (SEGA) is a rare, benign tumor that occurs mainly in children; complete resection can achieve cure. Guidance of surgery by combined intraoperative magnetic resonance imaging (iMRI) and functional neuronavigation is reported to achieve more radical resection and reduced complications. However, reports about the resection of SEGA with such guidance are rare. We report here our preliminary experience of the resection of SEGA guided by iMRI and neuronavigation, focusing on the feasibility, benefits, and pitfalls of this combination of techniques.

METHODS

We performed resection of SEGA guided by combined iMRI and functional neuronavigation in seven children. The first iMRI was performed when the surgeon believed that the tumor had been completely resected; the last iMRI was performed immediately after closure. Additional scans were performed as needed.

RESULTS

Successful resection was achieved in all seven patients using this combination of techniques. The iMRI scans detected residual tumor in three patients and a large, remote epidural hematoma in one patient. Further resection or other surgery was performed in these four patients. Complete resection was eventually achieved in all patients. There were no cases of surgery-related neurological dysfunction, except transient memory loss in one patient. No recurrence of tumor or hydrocephalus was observed in any patients during the follow-up period.

CONCLUSIONS

Resection of SEGA in children guided by combined iMRI and neuronavigation is feasible and safe. This combination of techniques enables a higher complete resection rate and reduces brain injury and other unexpected events during surgery.

Epilepsy in Tuberous Sclerosis Complex

Tuberous Sclerosis Complex (TSC) is an autosomal dominant multisystem disorder, characterized by the presence of hamartomatous lesions involving different organ systems, including the brain. Epilepsy is the most common presenting symptom, representing a major source of morbidity and mortality. Despite multiple antiepileptic drug combinations, in about two thirds of cases the patients present high-frequency drug-resistant epilepsy, and nonpharmacologic options may be considered. The aim of this work was to point out the current knowledge on epileptogenesis in TSC, the available medical therapies and diagnostic tools, and possible surgical strategies, with the intent to better understand the actual difficulties in controlling seizures and the results reported in the literature. There is also a section dedicated to the common association with cognitive impairment and the role of epilepsy control on its outcome.