New classification of epilepsy-related neoplasms: The clinical perspective

Brain tumor-associated epilepsies in adulthood: Current state of diagnostic and individual treatment options

Brain tumors are one of the most frequent causes of structural epilepsy and set a major burden on treatment costs and the social integrity of patients. Although promising oncological treatment strategies are already available, epileptological treatment is often intractable and requires lifelong epileptological care. Therefore, treatment strategies must be adapted to age-related needs, and specific aspects of late-onset epilepsy (LOE) must be considered. The practical implementation of individual decisions from tumor boards and the current state of the art in scientific knowledge about pathological mechanisms, modern diagnostic procedures and biomarkers, and patient-individualized treatment options into practical epileptological disease management is a prerequisite. This narrative review focuses on the current work progress regarding pathogenesis, diagnosis, and therapy. Exemplarily, interdisciplinary approaches for optimized individualized therapy will be discussed, emphasizing the combination of neurological-epileptological and oncological perspectives.

Polymorphous low-grade neuroepithelial tumor of the young with FGFR3-TACC3 fusion mimicking high-grade glioma: case report and series of high-grade correlates

Background

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described entity that can mimic high-grade glioma (HGG) in histologic and molecular features; however, factors predicting aggressive behavior in these tumors are unclear.

Methods

We present an indolent neuroepithelial neoplasm in a 59-year-old female with imaging initially suggestive of HGG, and a series of adult patients with HGG harboring FGFR3-TACC3 fusions are also presented for comparison.

Results

Pathology in the case patient revealed low-grade cytomorphology, microcalcifications, unusual neovascularization, and a low proliferation index. The lesion was diffusely CD34+ and harbored an FGFR3-TACC3 fusion and TERT promoter mutation. A diagnosis of PLNTY was therefore favored and the patient was observed with no progression at 15-month follow-up. In patients with HGG with FGFR3-TACC3 fusions, molecular findings included IDH-wildtype status, absence of 1p19q codeletion, CDKN2A loss, TERT promoter mutations and lack of MGMT promoter methylation. These patients demonstrated a median 15-month overall survival and a 6-month progression-free survival.

Conclusion

PLNTY is a rare low-grade entity that can display characteristics of HGG, particularly in adults. Presence of FGFR3-TACC3 fusions and other high-grade features should raise concern for a more malignant precursor lesion when a diagnosis of PLNTY is considered.

Neuroimaging in Adults and Children With Epilepsy

OBJECTIVE

This article discusses the fundamental importance of optimal epilepsy imaging using the International League Against Epilepsy-endorsed Harmonized Neuroimaging of Epilepsy Structural Sequences (HARNESS) protocol and the use of multimodality imaging in the evaluation of patients with drug-resistant epilepsy. It outlines a methodical approach to evaluating these images, particularly in the context of clinical information.

LATEST DEVELOPMENTS

Epilepsy imaging is rapidly evolving, and a high-resolution epilepsy protocol MRI is essential in evaluating newly diagnosed, chronic, and drug-resistant epilepsy. The article reviews the spectrum of relevant MRI findings in epilepsy and their clinical significance. Integrating multimodality imaging is a powerful tool in the presurgical evaluation of epilepsy, particularly in "MRI-negative" cases. For example, correlation of clinical phenomenology, video-EEG with positron emission tomography (PET), ictal subtraction single-photon emission computerized tomography (SPECT), magnetoencephalography (MEG), functional MRI, and advanced neuroimaging such as MRI texture analysis and voxel-based morphometry enhances the identification of subtle cortical lesions such as focal cortical dysplasias to optimize epilepsy localization and selection of optimal surgical candidates.

ESSENTIAL POINTS

The neurologist has a unique role in understanding the clinical history and seizure phenomenology, which are the cornerstones of neuroanatomic localization. When integrated with advanced neuroimaging, the clinical context has a profound impact on identifying subtle MRI lesions or finding the "epileptogenic" lesion when multiple lesions are present. Patients with an identified lesion on MRI have a 2.5-fold improved chance of achieving seizure freedom with epilepsy surgery compared with those without a lesion. This clinical-radiographic integration is essential to accurate classification, localization, determination of long-term prognosis for seizure control, and identification of candidates for epilepsy surgery to reduce seizure burden or attain seizure freedom.

Historical Overview of the "Firing" Liaison between Brain Tumors and Epilepsy

This review addresses, in a critical historical perspective, the link between seizures and endocranic neoplasms. Folkloric descriptions of epilepsy can be found in writings from ancient cultures. Hippocrates first provided a medical interpretation. In 1770, Tissot published Traité de l'épilepsie, a milestone in epileptology, whereas the 19th century is considered the golden era of epileptic studies. In 1882, the father of modern epileptology, Jackson, in his article Localized Convulsions from Tumour of the Brain, reported a case of a patient affected by typical Jacksonian seizures in the presence of a brain tumor. However, he did not establish a direct correlation between brain tumors and epilepsy, and an explanation for his clinical case was lacking. Before Jackson's article, other authors reported similar cases, but only Gairdner in 1834 published a report suggesting the concept of a direct relationship between epilepsy and a brain tumor. From the beginning until the mid of the 20th century several authors reported seizures attributed to intracranial tumors, and in recent years studies have focused on the pathogenesis of tumor-related seizures. Biochemical and molecular changes in brain tumors and their environment opened unprecedented working hypotheses on epileptogenesis and on treatment of epilepsy associated with brain tumors.

Clinical, Radiological, Pathological Features and Seizure Outcome With Surgical Management of Polymorphous Low-Grade Neuroepithelial Tumor of the Young Associated With Epilepsy

Objective

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a novel distinct epileptogenic neoplasm, and its clinical, imaging, histopathological, and molecular features were already known in the existing literature. We aimed to analyze the surgical management of PLNTY combined with these known characteristics.

Methods

Eight patients underwent surgical treatment in our center between December 2017 and December 2020, and the postoperative pathology was diagnosed as PLNTY. Their clinical data, imaging, pathological, molecular characteristics, and seizure outcome were retrospectively analyzed. Follow-up evaluations and a literature review were performed.

Results

The 8 patients included 1 woman and 7 men, aged between 5 and 51 years old (mean = 31.6, median = 29). The preoperative symptoms of all 8 cases were seizures. Four tumors were situated in the temporal lobes, and one of the four extratemporal tumors was in the occipital lobe and three were in the frontal lobe. Enlarged and gross total resections were performed in 2 cases and the other 6 cases, respectively. All cases exhibited intense labeling of CD34, and absence of 1p/19q codeletion and IDH1 or IDH2 mutation. B-Raf proto-oncogene (BRAF) V600E mutation was presented in 4 (66.7%) of 6 detected cases. The postoperative seizure outcome of Engel class I was achieved in 6 cases (75%).

Conclusion

PLNTY represents distinctive histologic, immunophenotypic and biomolecular features, and has high epileptogenicity. Early surgical intervention and enlarged resection of PLNTY associated with epilepsy will help to improve the postoperative seizure-free rate.

Lost in Transition: The Long and Winding Road Toward Epilepsy Surgery—An Analysis of Obstacles Prior to Surgery and Call for Orchestrated Health Care Efforts in Epilepsy

Difficult-to-treat epilepsy is defined as ongoing seizures despite adequate pharmacological treatment. This condition is affecting a significant percentage of epilepsy patients and is estimated to be as high as one-third of all patients. Epilepsy surgery, targeting the removal of the key parts of cerebral convolutions responsible for seizure generation and often including a structural lesion, can be a very successful approach. However, this necessitates careful patient selection by comprehensive investigations, proving the localization of the epileptogenic zone as well as measures to make such surgeries safe. With careful selection as a prerequisite, the percentage of patients achieving seizure freedom by neurosurgical intervention is high, approximating two-thirds of all epilepsy surgeries performed. In contrast, the average duration of a patient's pharmacoresistant focal epilepsy prior to surgery anywhere around the globe is around 20 years. Given that typical patients are ∼30 to 40 years of age at the time of surgery, many patients have been living with chronic seizures since childhood or adolescence. This means that most of these patients have been going through several stages of medical care for years or even decades, both as children and adults, without ever being fully investigated and/or selected for surgery which is concerning. Yet, there is no set standard for a timeline leading toward successful surgery in epilepsy. It is obvious that the average transit period from the moment of first seizure manifestation until the day of successful surgery takes much too long. This is the reason why we see these patients lost in transition.

Epileptic Activity Intrinsically Generated in the Human Cerebellum

Neoplastic or dysplastic neuronal tissue in the brain stem and cerebellum can become epileptogenic in pediatric patients. However, it is unknown whether such tissue may transform intrinsic properties of the human cerebellum, making it capable of generating epileptic population activity. We noninvasively detected epileptiform signals unaveraged in a pediatric patient with epilepsy due to a tumor in the middle cerebellar peduncle. Analysis of generators of the signals revealed that the cerebellum ipsilateral and contralateral to the tumor was the dominant interictal spike generator and could initiate ictal activity, suggesting that human cerebellum may become capable of intrinsically generating epileptic activity. ANN NEUROL 2020;88:418-422.

Uncommon low-grade brain tumors

The 2016 World Health Organization (WHO) classification of primary central nervous system (CNS) tumors includes numerous uncommon (representing ≤1% of tumors) low-grade (grades I-II) brain neoplasms with varying clinical behaviors and outcomes. Generally, gross tumor or maximal safe resection is the primary treatment. Adjuvant treatments, though their exact role is unknown, may be considered individually based on pathological subtypes and a proper assessment of risks and benefits. Targetable mutations such as BRAF (proto-oncogene B-Raf), TRAIL (tumor necrosis factor apoptosis inducing ligand), and PDGFR (platelet derived growth factor receptor) have promising roles in future management.

Polymorphous Low-Grade Neuroepithelial Tumor of the Young as a Partially Calcified Intra-Axial Mass in an Adult

Polymorphous low-grade neuroepithelial tumors of the young (PLNTYs) are recently described CNS tumors. Classically, PLNTYs are epileptogenic and are a subtype of a heterogeneous group of low-grade neuroepithelial tumors that cause refractory epilepsy, such as angiocentric gliomas, oligodendrogliomas, gangliogliomas, and pleomorphic xanthoastrocytomas. Although they are a relatively new entity, a number of imaging and histologic characteristics of PLNTYs are already known. We present the imaging and pathologic findings of such a tumor as well as the surgical approach and clinical management.

Acute symptomatic seizure due to tacrolimus-related encephalopathy after liver transplantation: two case reports

Liver transplantation is suitable for acute and chronic liver diseases that cannot be cured by other methods. Immunosuppressants such as azathioprine, methylprednisolone, cyclophosphamide, cyclosporine A, and tacrolimus have been applied to prevent rejection after liver transplantation. Among them, tacrolimus is generally effective in resisting rejection, and its main adverse reaction is nephrotoxicity. Tacrolimus-induced seizures are rarely reported. The present report describes trismus, restlessness, and generalized muscle twitching in a 44-year-old man and a 59-year-old man who received tacrolimus after liver transplantation. Tacrolimus-induced epilepsy was diagnosed by clinical symptoms and video-electroencephalography. After the patients developed epileptic symptoms, they received intramuscular injections of diazepam and phenobarbital. When the symptoms were relieved, the patients were treated with oral levetiracetam tablets. The tacrolimus was immediately stopped, and the epilepsy symptoms gradually disappeared after treatment with sedatives and levetiracetam. The patients continued taking the levetiracetam for approximately 2 weeks. No evidence of seizures occurred during the next 8 months. Although tacrolimus is reportedly effective against rejection after liver transplantation, tacrolimus-induced epilepsy should be carefully managed to prevent death. Additionally, epilepsy may rarely occur in patients with a normal blood concentration of tacrolimus. Further study on the mechanism of such neurological complications is needed.

Polymorphous Low-Grade Neuroepithelial Tumor of the Young: A Case Report with Genomic Findings

BACKGROUND

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently recognized epileptogenic neuroepithelial tumor. Despite its distinctiveness, its polymorphous histology and the nature of its oligodendrocyte-like cells remain unclear.

CASE DESCRIPTION

A 30-year-old, right-handed man was diagnosed with intractable epilepsy since 22 years of age. Magnetic resonance imaging revealed T2 signal hyperintensity and corresponding T1 signal hypointensity within the subcortical white matter of the right middle temporal gyrus. Positron emission tomography scan demonstrated hypometabolism in the right anterior temporal region. Electroencephalography and stereo-electroencephalography monitoring localized seizures to the right temporal lobe, allowing the patient to undergo right temporal lobectomy. Histologic sections demonstrated cortical dysplasia, white matter heterotopia, and hippocampal reactive gliosis without neuronal loss. Interestingly, an approximately 6-mm subcortical neoplasm was identified in the temporal lobectomy. It was composed of well-differentiated oligodendroglial-like cells but exhibited mild-to-moderate nuclear variability and pleomorphism, and mild infiltration into the overlying cortex without perineuronal satellitosis. No mitotic activity, microvascular proliferation, or necrosis was identified, and Ki-67 labeling index was less than 1%. The tumor was diffusely CD34 positive with moderate glial fibrillary acidic protein and retained ATRX staining, and demonstrated the presence of the BRAF V600E mutation. The tumor was negative for reticulin condensation, synaptophysin, SMI31, neuronal nuclei immunostains, and both the IDH1 mutation and 1p19q codeletion. Overall histologic findings were most consistent with PLNTY.

CONCLUSIONS

The correct diagnosis of PLNTY and its distinction from closely resembling low-grade neuroepithelial tumors is important. We hope our proposed diagnostic features will aid in its proper diagnosis and management.

A newly diagnosed case of polymorphous low-grade neuroepithelial tumor of the young

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described variant of low-grade neuroepithelial tumors that exhibits infiltrative growth, histopathological variability with frequently prominent oligodendroglioma-like components, intense labeling for CD34, absence of 1P/19Q codeletion, a distinct DNA methylation signature and genetic alterations involving MAP kinase pathway constituents of either the B-Raf proto-oncogene BRAF or fibroblast growth factor receptors 2 or 3 (FGFR2 and FGFR3). We here report a newly diagnosed case of PLNTY involving the temporal lobe in a 31-year-old man with chronic focal epilepsy. This tumor had histologic and immunophenotypic features similar to the recently described PLNTY and proved BRAF V600E mutant. Biomolecular profiling is becoming increasingly important in characterizing neuroepithelial tumors. Furthermore, biomolecular features such as CD34 expression and BRAF mutation have been reported to be significantly associated with the clinical behavior of these tumors. Like other low-grade neuroepithelial tumors, PLNTYs appear to be generally indolent with excellent seizure relief after total surgical resection. It is important to recognize cases of PLNTY in order to guide clinical management including the indication for surgery.