Dysembryoplastic Neuroepithelial Tumor Research Articles

Dysembryoplastic neuroepithelial tumor-like neoplasm of the septum pellucidum: review of 2 cases with chromosome 1p/19q and IDH1 analysis

Dysembryoplastic neuroepithelial tumor (DNT)-like neoplasms of the septum pellucidum are extremely rare. We reviewed 2 cases of DNT-like neoplasm of the septum pellucidum and specifically studied the immunohistochemical features and chromosomes 1p and 19q deletions. One case was a 26-year-old woman who complained of aggravated headache for 2 weeks. The other case was a 31-year-old female presenting with double vision for a month. Histological examinations showed that the lesions were composed of uniform oligodendrocytelike cells (OLCs) with obvious floating neurons in a mucin-rich background. Immunohistochemical studies revealed that both tumors were diffusely positive for Synaptophysin and Olig2. Sporadic neurons were clearly positive for NeuN. Loss of chromosome 1p/19q and isocitrate dehydrogenase 1(IDH1) mutations were not identified in both cases. It might indicate that these OLCs of DNT-like neoplasms were genetically different from glial tumors, although they showed close morphological similarities.

Meningioma in a 20-Month-Old Boy

A 20-month-old boy presented with a intraparenchymal mass in the right frontoparietal area manifesting as complex partial seizure, secondary generalization and left hemiparesis. Magnetic resonance images (MRI) of the brain showed inhomogeneously enhancing mass in the right frontoparietal area which has irregular margin and perilesional edema. Based on the radiological findings, a preoperative diagnosis was an intraaxial tumor, such as pilocytic astrocytoma or dysembryoplastic neuroepithelial tumor. The patient underwent a surgery including frontal craniotomy. The tumor had a partially extreme adherence to the surrounding brain tissue but it showed no dural attachment. Gross-total resection of the tumor was achieved. Postoperative follow-up computed tomography scans showed no residual tumor. The pathological findings confirmed the tumor as a WHO grade I meningioma, transitional type. Nine months after the surgery, follow-up brain MRI showed no recurrence of the tumor, porencephaly in site where the tumor was resected; the patient's symptoms had fully recovered. We report the case of a meningioma in a 20-month-old boy.

Incidental findings of mass lesions on neuroimages in children

Increasing use of neuroimaging in children has led to more incidental findings of CNS mass lesions, the management of which is uncertain. The authors' aims in this study are to describe these mass lesions and their evolution, as well as to discuss the management options and determine the prevalence of incidental CNS mass lesions at their pediatric clinic. A retrospective study was undertaken in children with primary CNS tumors who were younger than 18 years old and were admitted to the University Children's Hospital of Zurich, Switzerland, between January 1995 and December 2010. In 19 (5.7%) of 335 patients with newly diagnosed CNS tumors, the diagnosis of a CNS mass lesion was an incidental finding. Reasons for obtaining neuroimages in these 19 patients were head trauma (in 6 patients); research protocols (in 3); nasal/orbital malformations (in 2); endocrinological and psychiatric evaluations (in 2); and vertebral bone anomaly without neurological signs, absence seizures, congenital ataxia, recurrent vomiting, developmental delay, and "check-up" at the explicit request of the parents (in 1 patient each). Seven patients underwent immediate surgery for low-grade glioma (4 patients) and craniopharyngioma, ependymoma, and choroid plexus papilloma (1 patient each); and 12 were treated conservatively or were observed. Ten of 12 conservatively treated patients remained stable (median follow-up time 1.8 years) and the other 2 underwent delayed surgery because of tumor progression (medulloblastoma in one patient and fibrillary astrocytoma in the other). Clinicians are increasingly challenged by the discovery of incidental CNS mass lesions. A subgroup of such lesions (with typical imaging patterns such as tectal glioma and dysembryoplastic neuroepithelial tumor) can be monitored conservatively, clinically, and radiographically. Future prospective studies are needed to define optimal management strategies based on larger collections of natural histories, as well as to assess the true prevalence of incidental CNS mass lesions.

Increased tryptophan transport in epileptogenic dysembryoplastic neuroepithelial tumors

Dysembryoplastic neuroepithelial tumors (DNTs) are typically hypometabolic but can show increased amino acid uptake on positron emission tomography (PET). To better understand mechanisms of amino acid accumulation in epileptogenic DNTs, we combined quantitative α-[(11)C]methyl-L: -tryptophan (AMT) PET with tumor immunohistochemistry. Standardized uptake values (SUVs) of AMT and glucose were measured in 11 children with temporal lobe DNT. Additional quantification for AMT transport and metabolism was performed in 9 DNTs. Tumor specimens were immunostained for the L: -type amino acid transporter 1 (LAT1) and indoleamine 2,3-dioxygenase (IDO), a key enzyme of the immunomodulatory kynurenine pathway. All 11 tumors showed glucose hypometabolism, while mean AMT SUVs were higher than normal cortex in eight DNTs. Further quantification showed increased AMT transport in seven and high AMT metabolic rates in three DNTs. Two patients showing extratumoral cortical increases of AMT SUV had persistent seizures despite complete tumor resection. Resected DNTs showed moderate to strong LAT1 and mild to moderate IDO immunoreactivity, with the strongest expression in tumor vessels. These results indicate that accumulation of tryptophan in DNTs is driven by high amino acid transport, mediated by LAT1, which can provide the substrate for tumoral tryptophan metabolism through the kynurenine pathway, that can produce epileptogenic metabolites. Increased AMT uptake can extend to extratumoral cortex, and presence of such cortical regions may increase the likelihood of recurrent seizures following surgical excision of DNTs.

Memory in paediatric temporal lobe epilepsy: Effects of lesion type and side

This study investigated the role of underlying pathology on memory function of children with temporal lobe epilepsy (TLE). Memory was assessed in 44 children with TLE resulting from hippocampal sclerosis (HS) or dysembryoplastic neuroepithelial tumours (DNT), and 22 control children. Delayed story and paired associate recall performance was significantly more impaired in children with HS compared to those with DNT, irrespective of the affected side. Semantic memory was impaired in both HS groups, and also in the left DNT group. These results suggest a role for type, and to a lesser extent, side of pathology in the memory profile of children with TLE.

Epileptogenic brain lesions in children: the added-value of combined diffusion imaging and proton MR spectroscopy to the presurgical differential diagnosis

Focal cortical dysplasia (FCD), dysembryoplastic neuroepithelial tumors (DNTs), and gangliogliomas (GGs) share many clinical features, and the presurgical differential diagnosis of these lesions using conventional magnetic resonance imaging (MRI) is challenging in some cases. The purpose of this work was thus to evaluate the capacity of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS) to distinguish each lesion from the others. Seventeen children (mean age 9.0 ± 4.7years), who had been referred for epilepsy associated with a brain tumor and operated, were selected. Preoperative MRI examinations were performed on a 1.5T system and included anatomical images [T2-weighted, fluid-attenuated inversion recovery (FLAIR) and T1 pre- and post-injection images] as well as DWI and MRS [echo time (TE) = 30 and 135ms]. Apparent diffusion coefficient (ADC) values were calculated in the lesion and healthy control. MRS relative quantification consisted in normalizing each metabolite by the sum (S) of all metabolites (S(TE=135 ms) = NAA+Cr+Cho; S(TE=30 ms) = NAA+Cr+Cho+Glx+mI). Univariate and multivariate analyses were performed in order to determine which criteria could differentiate the different epileptogenic brain lesions. When taken alone, none of the MRI parameters was able to distinguish each disease from the others. Conventional MRI failed classifying two patients. When adding ADC to the linear discriminant analysis (LDA), one patient was still misclassified. Complete separation of the three groups was possible when combining conventional MRI, diffusion, and MRS either at long or short TE. This study shows the added-value of multimodal MRI and MRS in the presurgical diagnosis of epileptogenic brain lesions in children.

One Hundred and One Dysembryoplastic Neuroepithelial Tumors: An Adult Epilepsy Series With Immunohistochemical, Molecular Genetic, and Clinical Correlations and a Review of the Literature

Simple and complex forms of dysembryoplastic neuroepithelial tumors (DNTs) are readily recognizable but forms with diffuse growth pattern, and hybrid tumors, that is, mixed DNT and ganglioglioma (DNT/GG), are more contentious entities. Rare DNTs have shown aggressive behavior. We reviewed cortical growth patterns, immunophenotype (including CD34, nestin and calbindin), genetic profile, and outcome in 101 DNT in adults. Simple (n = 18), complex (n = 31), diffuse (n = 35) DNT, and mixed DNT/GG (n = 17) showed no difference in age of onset, associated seizure type, or outcome (67.5% free from seizure; mean follow-up, 6 years). CD34 was seen in 61%, calbindin in 57%, and nestin in 86% of all DNT types; these markers were less common in simple DNT. Peritumoral cortical changes (Layer I hypercellularity [61%], satellite nodules [51.6%]) were frequent, but dyslamination (cortical dysplasia) was not identified. Molecular genetic abnormalities identified in 17 cases were IDH1 mutation (n = 3), 1p/19q loss (n = 10), isolated loss 9q (n = 2), and PTEN loss (n = 3), which were not associated with tumor type or location, higher cell proliferation, or distinguishing clinical features (mean age of epilepsy onset, 9 years; age at surgery = 31 years; 69% free from seizure); none had progression on magnetic resonance imaging (mean follow-up, 6 years). No single feature was predictive of seizure-free outcome, but there was a trend for better outcome in CD34-positive tumors (p = 0.07). One case has shown transformation to a higher grade. This study supports the existence of a range of subtypes of DNT some with overlapping features with ganglioglioma; molecular genetic abnormalities were not predictive of atypical behavior.

Factors associated with seizure freedom in the surgical resection of glioneuronal tumors

Gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNETs) are low-grade brain tumors of glioneuronal origin that commonly present with seizures. Achieving seizure control in patients with glioneuronal tumors remains underappreciated, as tumor-related epilepsy significantly affects patients' quality-of-life. We performed a quantitative and comprehensive systematic literature review of seizure outcomes after surgical resection of GGs and DNETs associated with seizures. We evaluated 910 patients from 39 studies, and stratified outcomes according to several potential prognostic variables. Overall, 80% of patients were seizure-free after surgery (Engel class I), whereas 20% continued to have seizures (Engel class II-IV). We observed significantly higher rates of seizure-freedom in patients with ≤1 year duration of epilepsy compared to those with >1 year of seizures [odds ratio (OR) 9.48; 95% confidence interval (CI) 2.26-39.66], and with gross-total resection over subtotal lesionectomy (OR 5.34; 95% CI 3.61-7.89). In addition, the presence of secondarily generalized seizures preoperatively predicted a lower rate of seizure-freedom after surgery (OR 0.40; 95% CI 0.24-0.66). Outcomes did not differ significantly between adults and children, patients with temporal lobe versus extratemporal tumors, pathologic diagnosis of GG versus DNET, medically controlled versus refractory seizures, or with the use of electrocorticography (ECoG). Extended resection of temporal lobe tumors, with hippocampectomy and/or corticectomy, conferred additional benefit. These results suggest that early operative intervention and gross-total resection are critically important factors in achieving seizure-freedom, and thus improving quality-of-life, in patients with glioneuronal tumors causing epilepsy.

Dysembryoplastic neuroepithelial tumor and probable sudden unexplained death in epilepsy: a case report

IntroductionThis is the first report of the case of a patient with a natural history of dysembryoplastic neuroepithelial tumor associated with probable sudden unexplained death in epilepsy. These tumors are benign, arising within the supratentorial cortex. Over 100 cases have been reported in the literature since the first description by Daumas-Duport in 1988.Case presentationA 24- year-old Caucasian woman had a long period of intractable complex partial seizures, sometimes with tonic-clonic generalization and neuropsychological abnormalities. Magnetic resonance imaging showed a cortico-subcortical parietal tumor with all the characteristics of these types of tumors. After 14 years of evolution, our patient died suddenly during sleep.ConclusionTo the best of our knowledge, this is the first case of probable sudden unexplained death in symptomatic epilepsy due to dysembryoplastic neuroepithelial tumor with natural history. Early and complete excision, with functional studies before and during the surgery, leads to better control of seizures, avoiding neuropsychological changes and the risk of death. Patients with refractory epilepsy should be evaluated for any sleep disorders and should have complete cardiology assessments including electrocardiographic evaluation of cardiac rhythm disturbances.

Nogo-A: a useful marker for the diagnosis of oligodendroglioma and for identifying 1p19q codeletion

The differential diagnosis between oligodendrogliomas and other gliomas remains a critical issue. The aim of this study is to verify the diagnostic value of Olig-2, Nogo-A, and synaptophysin and their role in identifying 1p19q codeletion. A total of 168 cases of brain tumors were studied: 24 oligodendrogliomas, 23 anaplastic oligodendrogliomas, 2 oligoastrocytomas, 2 anaplastic oligoastrocytomas, 30 glioblastoma multiforme, 2 diffuse astrocytomas, 4 anaplastic astrocytomas, 10 pilocytic astrocytomas, 9 ependymomas, 12 anaplastic ependymomas, 10 central neurocytomas, 10 meningiomas, 10 choroid plexus papillomas, 10 dysembryoplastic neuroepithelial tumors, and 10 metastases. All cases were immunostained with Olig-2, Nogo-A, and synaptophysin. In 79 cases, the status of 1p/19q had already been assessed by fluorescence in situ hybridization. Thus, in selected cases, fluorescence in situ hybridization was repeated in areas with numerous Nogo-A-positive neoplastic cells. Nogo-A was positive in 18 (75%) of 24 oligodendrogliomas, 8 (80%) of 10 dysembryoplastic neuroepithelial tumors, 6 (20%) of 30 glioblastoma multiforme, and 2 (20%) of 10 pilocytic astrocytomas. Olig-2 stained 22 (91.6%) of 24 oligodendrogliomas and all dysembryoplastic neuroepithelial tumors but also 24 (80%) of 30 glioblastoma multiforme and 8 (80%) of 10 pilocytic astrocytomas. Finally, synaptophysin stained 13 (54.1%) of 24 oligodendrogliomas, 3 (10%) of 30 glioblastoma multiforme, 1 (10%) of 10 pilocytic astrocytomas, and all neurocytomas. Among the 79 tested cases, original fluorescence in situ hybridization showed 1p/19q codeletion in 12 (52.2%) of 23 oligodendrogliomas, 8 (38%) of 21 anaplastic oligodendrogliomas, and 1 (4%) of 25 glioblastoma multiforme. However, after carrying out the Nogo-A-driven fluorescence in situ hybridization, 1p/19q codeletion was observed in 8 additional cases. Nogo-A is more useful and specific than Olig-2 in differentiating oligodendrogliomas from other gliomas. Furthermore, using a Nogo-A-driven fluorescence in situ hybridization analysis, it is possible to identify a larger number of 1p19q codeletions in gliomas.

CD34 and microtubule‐associated protein 2 expression in dysembryoplastic neuroepithelial tumours with an emphasis on dual expression in non‐specific types

Three histological variants of dysembryoplastic neuroepithelial tumour (DNT) have been described, namely, simple, complex and non-specific. However, the concept of non-specific variants of DNT remains controversial, because they cannot be accurately distinguished by histological findings alone from ordinary gliomas. The aim was to characterize further the non-specific histological forms of DNT. Forty-one DNTs classified as three histological forms were investigated with CD34 and microtubule-associated protein 2 (MAP2) immunohistochemistry. CD34 immunoreactivity was more frequently observed in non-specific DNT types (16/18 cases; 88.9%) than in classic types (6/23 cases; 26.1%) (P < 0.001). Peritumoral CD34 expression of non-neoplastic cells was significantly associated with CD34-positive tumours (20/22 cases; 90.9%) than with CD34-negative tumours (3/19 cases; 15.8%) (P < 0.001). MAP2 positivity in oligodendroglia-like cells or glial elements was significantly different between classic types and non-specific types (P = 0.025). CD34 and MAP2 immunoreactivities were significantly more frequent in non-specific types (83.3%) than in simple (10%) and complex forms (30.8%) (P < 0.001). Non-specific DNTs are glioneuronal tumours that have a heterogeneous population of cells with more immature neuronal and glial phenotypes. Furthermore, with regard to practical implications, combined analysis of CD34 and MAP2 is useful in distinguishing DNTs from particularly diagnostically challenging mimics.

Microsurgical resection of deep-seated lesions using transparent tubular retractor: pediatric case series

To facilitate effective resection of deep-seated brain lesions without causing significant trauma to the overlying cortex, the authors used a transparent plastic tubular retractor to approach these lesions. Between July 2009 and January 2011, we used an 11-mm diameter transparent plastic tubular retractor in combination with a frameless stereotactic navigation system to remove 18 deep lesions. Gross total resection of the lesions was achieved in 14 of 18 patients, and subtotal removal occurred in four patients. Effective resection of lesions was achieved in all patients through small size craniotomy window and small cortical incision. The histopathologic diagnosis was established in all 18 patients: 3 hematomas, 3 cavernous angioma, 7 low-grade glioma, 2 dysembryoplastic neuroepithelial tumor, 1 choroid plexus papilloma, 1 abscess, and 1 meningioma. Microsurgery using a transparent tubular retractor guided by a neuronavigation system facilitated accurate and effective removal of these deep-seated brain lesions.

Epilepsy surgery in children with developmental tumours

We report our experience regarding evaluation, surgical treatment and outcomes in a population of 21 children with histopathologically confirmed developmental tumours [nine dysembryoplastic neuroepithelial tumours (DNET), ten gangliogliomas (GG) and two gangliocytomas (GC)] and related epilepsy, analyzing video-EEG, MRI and neuropsychological data, before and after surgery. Most children had focal epilepsy correlating well with lesion location. One patient had epileptic spasms and generalized discharges. Tumours were located in the temporal lobe in 13 patients. Mean age at surgery was 11.16 years. Postsurgical MRI showed residual tumour growth in one DNET. One child had a recurrent ganglioglioma with anaplastic transformation. At latest follow-up (mean 4.68 years) 95.2% of patients were seizure-free and no significant neuropsychological declines were observed. Evidence from our study suggests that, in this setting, surgery should be performed before criteria for refractory epilepsy are met, particularly in cases with early seizure onset, in order to optimize cognitive outcome.

Dysembryoplastic neuroepithelial tumor and calcifying pseudoneoplasms of the neuraxis: a collision of two seizure-associated lesions

Dysembryoplastic neuroepithelial tumor (DNET) is a benign glioneuronal neoplasm typically associated with intractable, partial complex seizures in children and young adults. The authors present a case in which a DNET in a 45-year-old male was accompanied by a so-called "calcifying pseudoneoplasm of the neural axis" (CPNA), a rare tumefactive lesion considered reactive in nature. An MRI scan of the brain revealed a right temporal lobe abnormality with characteristics of DNT but no apparent calcification. Histologically, it exhibited classic features of DNET and an overlying meningeal- based, partially ossified, chondrocalcific lesion morphologically characteristic of CPNA. The association of DNET and CPNA has not been previously reported. The literature relevant to these two seizure-associated lesions is reviewed.

Magnetoencephalography and awaking anesthesia in microsurgical resection of dysembryoplastic neuroepithelial tumor in function areas

Objective To summarize our experience on application of magnetoencephalography(MEG) and awaking anesthesia in microsurgical treatment of dysembryoplastic neuroepithelial tumors in the functional areas.Methods The range of the functional area was largely defined by MEG;intraoperative cortical electrical stimulation was used under awaking anesthesia to identify the border of function area and dysembryoplastic neuroepithelial tumors.Dysembryoplastic neuroepithelial tumors were resected under microscope in four patients and the outcomes of the patients were observed.Results Satisfactory outcomes were obtained in the 4 patients and there were no injuries in the function area.No epileptic seizures or recurrence of dysembryoplastic neuroepithelial tumors were found during long term follow-up.Conclusion Combined treatment using MEG and awaking anesthesia contributes to safe and effective surgical treatment of dysembroplastic neuroepithelial tumors in the function areas.

Misdiagnosis of Epileptic Seizures as Manifestations of Psychiatric Illnesses

Epileptic seizures may be misdiagnosed if they manifest as psychiatric symptoms or seizures occur in patients with known psychiatric illness. We present clinical profiles of six patients with epilepsy (three male, mean age 39 ± 12 years) that presented with prominent psychiatric symptoms. Two patients had pre-existing psychiatric illnesses. Three patients were initially diagnosed with panic attacks, two with psychosis, and one with schizophrenia. Five patients had temporal lobe epilepsy (TLE) while the sixth patient was subsequently found to have absence status epilepticus (SE). Cranial computed tomogram (CT) including contrast study was unremarkable in five patients and showed post-traumatic changes in one patient. Cranial magnetic resonance imaging (MRI) revealed dysembryoplastic neuroepithelial tumour (DNET) in one patient, cavernous hemangioma in one, and post-traumatic changes plus bilateral mesial temporal sclerosis in another patient but it was normal in two TLE patients. Routine electroencephalography (EEG) revealed absence SE in one patient but it was non-diagnostic in the TLE patients. Video-EEG telemetry in the epilepsy monitoring unit (EMU) was necessary to establish the diagnosis in four TLE patients. None of the patients responded to medications aimed at treating psychiatric symptoms alone. Two patients required surgery while the other four required treatment with anti-epileptic drugs. All the patients had favorable response to the treatment of their epilepsy. This case series illustrates that epileptic patients may experience non-convulsive seizures that might be mistaken as primary psychiatric illnesses. In this subset of patients, evaluation by an epileptologist, MRI of the brain, and/or video-EEG telemetry in an EMU was necessary to confirm the diagnosis of epilepsy if routine EEGs and cranial CT are normal.

Use of a minimally invasive tubular retraction system for deep-seated tumors in pediatric patients

Microsurgical removal is the preferred treatment for most deep-seated, intraaxial tumors in the pediatric population. The feasibility of surgery as an option has improved with advances in surgical technology and technique. Tubular retractors disperse retraction forces over a greater surface area than do conventional retractors, which can lower the risk of ischemic complications. The authors describe their experience utilizing a new tubular retractor system specifically designed for cranial applications in conjunction with frameless neuronavigation. The Vycor ViewSite retractor was used in 4 pediatric patients (ages 15 months and 9, 10, and 16 years) with deep-seated intraaxial tumors. The lesions included a papillary tumor of the pineal region, a low-grade astrocytoma in the occipital lobe, a dysembryoplastic neuroepithelial tumor arising from the basal ganglia, and an intraventricular low-grade glioma. The extent of white matter damage along the surgical trajectory (based on T2 or FLAIR and diffusion restriction/apparent diffusion coefficient signals) and the extent of resection were assessed on postoperative imaging. Satisfactory resection or biopsy was achieved in all patients. A comparison of pre- and postoperative MR imaging studies revealed evidence of white matter damage along the surgical trajectory in 1 patient. None of the patients demonstrated new neurological deficits postoperatively. Obtaining surgical access to deep-seated, intraaxial tumors is challenging. In this small series of pediatric patients, the combination of the ViewSite tubular retractor and frameless neuronavigation facilitated the surgical approach. The combination of these technologies adds to the armamentarium to safely approach tumors in deep locations.

Usefulness of 13N-NH3 PET in the evaluation of brain lesions that are hypometabolic on 18F-FDG PET

We investigated the usefulness of (13)N-NH(3) PET in characterizing brain lesions which show hypometabolism on (18)F-FDG PET. (13)N-NH(3) PET was performed in 18 patients with brain lesions (in 14 for initial diagnosis and in 4 for detection of astrocytoma recurrence) that showed hypometabolism compared with normal brain tissue on (18)F-FDG PET. The diagnoses were ten gliomas, one metastatic tumor, one dysembryoplastic neuroepithelial tumor (DNT), and six non-neoplastic lesions (including three cases of radiation necrosis, two cases of encephalitic foci, and one ischemic lesion). Diagnosis was verified by histopathological examination in 13 patients or was established by clinical follow-up and additional investigations in the remainder. Seven of 12 brain tumors (58%, sensitivity) showed increased (13)N-NH(3) uptake despite hypometabolism on (18)F-FDG PET. The three low-grade gliomas, one metastatic tumor, and one DNT showed decreased (13)N-NH(3) uptake. The mean (±SD) uptake ratio of (13)N-NH(3) was significantly higher than that of (18)F-FDG (1.24 ± 0.57 vs. 0.67 ± 0.21, P < 0.01) in the tumors. By contrast, all six non-neoplastic lesions showed decreased (13)N-NH(3) uptake (100% specificity). The mean (±SD) uptake ratio of (18)F-FDG and (13)N-NH(3) in the non-neoplastic lesions was 0.68 ± 0.15 and 0.70 ± 0.19, respectively, and there was no significant difference between them (P > 0.05). The mean (±SD) uptake ratio of (13)N-NH(3) in the tumors was significantly higher than that in the non-neoplastic lesions (1.24 ± 0.53 vs. 0.70 ± 0.19, P < 0.05). The preliminary results of this study suggest that (13)N-NH(3) PET may be helpful to detect and differentiate brain tumors which show hypometabolism on (18)F-FDG PET from non-neoplastic lesions with high specificity, especially for cerebral astrocytomas, but the sensitivity is relatively limited.

Diffuse hemispheric dysembryoplastic neuroepithelial tumor: a new radiological variant associated with early-onset severe epilepsy

The authors describe the clinical and radiological features in 3 children with a diffuse hemispheric dysembryoplastic neuroepithelial tumor (DNET) presenting with severe epilepsy and a previously unreported and characteristic MR imaging appearance. The DNET is a well-recognized cause of focal epilepsy, usually with a very good response to resection. These tumors are usually intracortical, and most commonly arise in the temporal lobe or frontal lobes. Radiologically they are usually sharply demarcated, and show little contrast enhancement. Three children (2 boys and 1 girl) presented at 14, 17, and 22 months of age with epileptic seizures. The seizures were focal motor or complex focal. One patient had epileptic spasms. The response to antiepileptic drug therapy was poor. Motor and cognitive development was delayed in all patients. One patient developed a severe epileptic encephalopathy, with regression of motor and cognitive skills. Her electroencephalogram obtained at that time showed hypsarhythmia. Admission MR imaging showed a diffuse unilateral abnormality involving frontal, temporal, and parietal lobes with little or no mass effect. There was involvement of both gray and white matter, with a striking sparing of the internal capsule in spite of apparent tumor throughout the basal ganglia and thalamus. In 2 patients there was prominent expansion of cortical gyri by tumor. In 1 child the initial radiological diagnosis was a middle cerebral artery infarct. On subsequent review the radiological diagnosis was thought to be low-grade glioma in all patients. The first patient underwent 2 limited resections involving the temporal lobe. He has continued to have poorly controlled seizures and severe behavioral and cognitive problems. The other patients had subtotal resection to the level of the internal capsule. One patient is currently seizure free 24 months postsurgery, but remains cognitively impaired. The patient in Case 3 is having some seizures 3.5 years postsurgery and remains hemiplegic, but the regression has reversed and she is making steady developmental progress. The pathological specimens showed the typical features of a DNET in all cases. This striking radiological pattern has not previously been described as a feature of a DNET. Recognition of this radiological pattern in young children with epilepsy will allow early consideration for resection, which may lead to improved long-term cognitive outcome.

Pathological spectrum of neuronal/glioneuronal tumors from a tertiary referral neurological Institute

Neuronal/glioneuronal tumors are uncommon neoplasms of the CNS with frequent association with refractory epilepsy. Reports documenting the entire spectrum of neuronal/glioneuronal tumors are scarce in the literature. Zulch et al. from Germany in a large series reported that neuronal/glioneuronal tumors accounted for 0.4% (38/9000 cases) of all brain tumors, with similar incidence reported from Japan (0.4%), with higher incidence from Korea (2.1%). However, data from the Indian subcontinent are lacking. We reviewed 244 cases of neuronal/glioneuronal tumors of the CNS diagnosed over the last decade at our Institute and they constituted 0.86% of all CNS tumors (244/28061) received in that period. Mean age at presentation was 25.06 years (range: 1-75 years) with male preponderance (M:F = 1.54 : 1). The majority occurred in third decade (76 cases, 31.4%), with only few cases occurring beyond fifth decade (13 cases, 5.3%). Ganglioglioma/gangliocytoma (94 cases, 38.52%) was the most frequent followed by central neurocytoma (86 cases, 35.24%), paraganglioma (32 cases, 13.52%), dysembryoplastic neuroepithelial tumors (DNET) (21 cases, 8.6%), desmoplastic infantile astrocytoma/desmoplastic infantile ganglioglioma (DIA/DIG) (6 cases, 2.45%), papillary glioneuronal tumor (PGNT) (3 cases, 1.22%) and rosette-forming glioneuronal tumor (RGNT) (1 case, 0.4%). Association with seizures was noted in 40.95% of cases. Glioneuronal tumors are an expanding group of tumors with varying spectra of morphologic patterns and biological behavior. An improved understanding has direct clinical implications for optimizing current treatments and developing novel therapeutic approaches. Although most glioneuronal tumors carry a favorable prognosis, other factors such as inaccessibility to surgical resection and rarely, malignant transformation, make it difficult to accurately predict the biological behavior based on histopathology alone. Reliable prognostic markers remain to be defined.