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Keywords:

  • dysembryoplastic neuroepithelial tumors (DNETs);
  • pediatric;
  • recurrence;
  • neuropsychologic outcome

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES

BACKGROUND:

Dysembryoplastic neuroepithelial tumors (DNETs) are benign glioneuronal tumors that occur in children. These tumors are characterized by seizures, lack of neurologic deficits, and a seemingly benign course after resection.

METHODS:

A retrospective review was conducted of data relating to 11 children diagnosed with DNETs between January 1988 and December 2007 at St. Jude Children's Research Hospital. This report documented the clinical features, neurocognitive function, and treatment outcomes in this institutional series.

RESULTS:

The patient cohort included 8 boys and 3 girls (median age at diagnosis, 10 years); all patients presented with seizures: 4 complex partial, 3 generalized tonic-clonic, 2 absence, 1 partial simple, and 1 not classified. Of the 11 patients, 1 died of cardiac fibrosis, and tumors recurred or progressed in 4 (36%) patients. Seizure control was achieved in all patients but 1. Of the 9 patients who completed neuropsychologic testing, only 3 (33%) functioned at or above the expected level of same-age peers.

CONCLUSIONS:

The high recurrence and progression rates of DNETs and the high rate of abnormal neurocognitive test results noted in the current study highlight the need for regular follow-up and appropriate academic counseling of children with these tumors. Cancer 2010. © 2010 American Cancer Society

Dysembryoplastic neuroepithelial tumors (DNETs), first described in 1988 by Daumas-Duport et al,1 are rare benign glioneuronal tumors occurring most commonly in children and young adults. Clinically, DNETs present as seizures before the age of 20 years in patients with a normal intelligence quotient (IQ).1, 2 Pathologically, the characteristic features of these tumors are a nodular architecture and a specific glioneuronal element, which typically contains oligodendrocyte-like cells in a columnar or alveolar pattern and “floating neurons” against a myxoid matrix.1 Neuroimaging findings confirm the cortical location and lack of edema or mass effect of DNETs.1, 3-5 Local recurrence occurs rarely after gross (macroscopic) total resection (GTR).1-3, 6, 7 Herein, we report clinical, pathologic, radiologic, and outcome data for 11 children with a diagnosis of DNET who were treated at St. Jude Children's Research Hospital (SJCRH), with emphasis on data regarding recurrent disease and neurocognition.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES

We conducted a retrospective study of the patients diagnosed with DNET between January 1988 and December 2007 at SJCRH. The fourth edition (2007) of the World Health Organization (WHO)'s classification of tumors of the nervous system8 was used to determine the pathologic criteria for diagnosis; the presence of an specific glioneuronal element was required to make a firm diagnosis of DNET. DNETs were divided into simple and complex forms, as described in the WHO classification; essentially, complex DNETs contain glial nodules but simple DNETs do not. Of 1589 patients with newly diagnosed brain tumors, 11 patients (0.7%) were diagnosed with DNETs during the study period. Medical records were reviewed for clinical data as well as radiologic and pathologic features at the time of diagnosis. Results of comprehensive neurologic examination by a neurologist, visual field testing, and neurocognitive evaluations were also obtained and reviewed.

Neurocognitive evaluations were completed for 9 of 11 patients. A retrospective review revealed that evaluations were conducted by using various measures according to the presenting clinical question, age, and year of evaluation. Intellect and academic achievement were assessed using the Wechsler Intelligence Scales for Children (WISC-R or WISCIII), the Wechsler Adult Intelligence Scale (WAIS-III), the Woodcock Johnson Test of Academic Achievement (WJ-R or WJ-Ach), the Wide Range Achievement Test (WRAT-R or WRAT-III), the Wechsler Individual Achievement Test, the Kaufmann Survey of Early Academic and Language Skills, or the McCarthy Scales of Children's Abilities. The Developmental Test of Visual-Motor Integration was also used. Measures of memory function were derived from the Wide Range Assessment of Memory and Learning, WISCIII, or McCarthy Scales of Children's Abilities. Scores from these tests were adjusted for age by using general population norms with a mean of 100 and a standard deviation of 15.

Parents were asked to complete the Behavioral Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL). The BRIEF is a questionnaire completed by parents and provides a measure of 8 aspects of executive function, processes by which a child can direct thought, action, and emotion. The CBCL provides 3 measures of competence (Activities, Social, and School) as well as measures of internalizing and externalizing behavior. Syndromes scored from the CBCL are Aggressive Behavior, Anxious/Depressed, Attention Problems, Rule-Breaking Behavior, Social Problems, Somatic Complaints, Thought Problems, and Withdrawn/Depressed. Six additional diagnostic-oriented areas are also assessed: Affective Problems, Anxiety Problems, Somatic Problems, Attention Deficit/Hyperactivity Problems, Oppositional Defiant Problems, and Conduct Problems.

Assessment reports generated by the evaluating clinician were reviewed. The reports provided either actual standard scores, descriptive labels for the level of performance, or both. Descriptive labels for standard scores are as follows: average (90-109), high average (110-119), superior (120-129), very superior (130+), low average (80-89), borderline (70-79), and deficient (≤69). Clinically significant levels of each measure derived from the parent report were also described.

In addition, radiologic characteristics, surgical extent of resection, disease recurrence patterns, and outcome data were reviewed. The extent of surgical resection was classified into 1of 5 categories on the basis of the surgeon's report and postoperative images as follows: 1) GTR: no visible tumor left; 2) near-total resection: removal of >90% but <100% of tumor; 3) subtotal resection: removal of 50% to 89% of the tumor; 4) partial resection: removal of 10% to 49% of the tumor; or 5) biopsy: removal of <10% of the tumor. The follow-up time was calculated as the time between the date of diagnosis (ie, date of first craniotomy) and the date of last follow-up.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES

Clinical Characteristics

Our patient cohort was comprised of 8 boys and 3 girls, with a median age at diagnosis of 10 years (range, 5.1-16.2 years). All patients presented with seizures at the time of diagnosis: 4 had complex partial (CP), 3 had generalized tonic-clonic (GTC), 2 had absence, and 1 had simple partial seizures; in 1 patient, the type of seizure could not be classified. In Patient 9, the CP seizure evolved to a GTC seizure. The median age of seizure onset was 9 years (range, 4-14 years), and the median time between seizure onset and surgery was 12 months (range, 0.5-60 months). Patients had a family history of seizures (n = 4), multiple sclerosis (n = 1), and bipolar disorder (n = 1).

Radiologic and Histopathologic Features

Radiologic data were consistent with those from the literature3-5 with regard to cortical location, hypointensity on T1 and hyperintensity on T2, enhancement, cystic component, edema, calcification, and bone remodeling (Figs. 1 and 2). In addition, the histopathologic features were consistent with those published previously (Fig. 3).1, 2, 6-8

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Figure 1. Computed tomography scan of the brain of Patient 6 showing (A) a hypodense lesion with (B) no enhancement noted after the injection of contrast dye. Bone remodeling is evident on both images (arrows).

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Figure 2. Magnetic resonance image of the brain of Patient 6 showing (A) a hypointense lesion on T1 and (B) a hyperintense lesion on T2. (C) Postcontrast imaging demonstrates partial enhancement (arrows).

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Figure 3. Microcystic nodules (A) are characteristic of dysembryoplastic neuroepithelial tumors and (B) demonstrate myxoid degeneration. The specific glioneuronal element is characterized by (C) columns of oligodendrocyte-like cells between microcysts and (D) neurons that “float” within the microcysts. (A, C, and D: H & E; B: Alcian blue and periodic acid-Schiff staining).

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Patient Outcome

At the time of last follow-up, all patients were alive: 8 had no evidence of radiologic disease (NED) and 3 had stable radiologic disease (SD). The median follow-up time was 9.7 years (range, 1-15.7 years). One patient whose status had been NED at the time of last follow-up died of cardiac fibrosis 6 years later.

A total of 18 surgical resections were performed: 6 patients underwent 1 resection each, 3 patients underwent 2 resections each, and 2 patients underwent 3 surgical resections each (Table 1). The reasons for the repeated craniotomies were recurrent disease that was detected radiologically after GTR (n = 3), progression of a residual tumor (n = 2), worsening seizures (n = 1), and residual disease (n = 1).

Table 1. Clinical, Surgical, and Seizure Data
PatientAge at Diagnosis, YearsTumor LocationVF DefectSeizure TypeAEDDuration Between Seizure to Surgery, YearsSeizure Control After SurgeryExtent of First ResectionExtent of Second ResectionExtent of Third ResectionDisease Status at Time of Last Follow-Up
  • VF indicates visual field; AED, antiepilepsy drugs; QA, quadrantanopia; SP, simple parietal; Sens, sensory; GTR, gross (macroscopic) total resection; NED, no evidence of disease; CP, complex partial; NA, not available; NTR, near-total resection; SD, stable disease; GTC, generalized tonic clonic; STR, subtotal resection; HH, homonymous hemianopia; BX, biopsy.

  • a

    The diagnosis of absence seizure was based on retrospective history from family and patients that was taken after the surgery; no electroencephalography was performed to confirm.

  • b

    The patient underwent a computed tomography scan shortly after surgery that demonstrated a mass, but the family deferred surgery for 5 years.

  • c

    The patient was blind in 1 eye because of congenital glaucoma and had QA in the other eye.

  • d

    The duration from seizure to surgery in this patient was only 2 weeks.

  • e

    The VF test used was a confrontational test administered by a neurologist.

  • f

    The patient died of a cause not related to his disease after last contact.

  • g

    The patient was seizure free for 4 years. The seizures then recurred and progressed during the next 8 years until a second resection was performed because of radiologic evidence of disease progression.

  • h

    The patient failed 11 different AED until the second surgery, at which time he required only 2 AED after second surgery for 2 years and was able to withdraw from AED therapy without recurrence of his seizures.

  • i

    The patient underwent biopsy and, after 10 days, definite surgery. Five months later, the patient developed seizures, but magnetic resonance imaging was negative for a tumor. Approximately 4 years later, surgery was performed on the epileptic focus; no tumor was found.

110.2TemporalQASP-SensCarbamazepine  Levetiracetam3.8ResolvedGTRNED
25.1FrontalCPCarbamazepine1ResolvedGTRNED
39.2TemporalAbsenceaCarbamazepine0.3ResolvedGTRGTRNED
415ParietalNormalNAPhenytoin5bResolvedNTRSD
516.2TemporalGTCPhenytoin2ResolvedGTRNED
69TemporalQAcAbsenceaCarbamazepine1ResolvedGTRGTRGTRNED
713.7Temporal-parietal  -occipitalQACPCarbamazepine0.4ResolvedNTRGTRNED
815.1Temporal–parietalGTCLevetiracetam0.0dControlledNTRSD
95.5Temporal–parietalHHeCP[RIGHTWARDS ARROW]GTCCarbamazepine0.8ResolvedGTRNEDf
10g6TemporalCPZonisamideh  Oxcarbazepine1.5ResolvedSTRSTRSD
11i11.6TemporalNormalGTCValproic acid  Phenobarbital1.8ResolvedBXGTRGTRNED

Patient 10 developed a seizure that recurred 4 years after the first craniotomy and continued to worsen over 8 years, although there was no radiologic progression. Twelve years after his first surgery, progressive disease was detected by magnetic resonance imaging; therefore, a second surgery was performed, and the pathology report revealed the presence of a tumor. The patient became seizure free 2 years after his second craniotomy.

Patient 11 demonstrated no signs of radiologic disease progression, but craniotomy was performed for recurrent seizures; no tumor was found in the epileptic focus. The median time to disease recurrence or progression was 30 months (range, 23-144 months). Seizures in all patients except Patient 8 were resolved by the time of last follow-up. At the time of last follow-up, the seizures in Patient 8 (1 of the 3 patients with SD) were being controlled by single-agent anticonvulsant therapy.

Neurologic Findings, Visual Field Testing, and Neurocognitive Testing

Ten patients were comprehensively examined by a neurologist at least once during their follow-up. Except for visual field deficits, only 1 patient (Patient 4) had abnormal neurologic findings, which were partly related to the surgery. Visual field testing was administered in 6 patients, and some defect was documented in 4 patients (67%): 3 had quadrantanopia and 1 patient had hemianopia. One patient (Patient 6) was blind in the right eye because of congenital glaucoma and also had quadrantanopia in the left eye.

At the time of the retrospective chart review, 20 neurocognitive evaluations had been completed in 9 of 11 patients (1 evaluation in 4 patients, 2 evaluations in 1 patient, 3 evaluations in 2 patients, and 4 evaluations in 2 patients). Patients were ages 5 to 19 years at the time of evaluation and were 1 month to 6 years after resection. Of the 9 patients, 8 received tests of overall intellect, 7 received tests of academic function, 6 received tests of visual motor integration and memory, and 2 received tests of processing speed. At the most recent evaluation, overall cognitive function and intellect tests indicated that only 3 patients were functioning at or above the average range for healthy same-age peers (Table 2). The remaining 5 patients (62.5%) who had been tested had low average or deficient overall intellectual function. Assessment of academic achievement demonstrated that only 3 patients were average or above average for reading and spelling, whereas only 4 patients were average or above average for math. Of the 8 school-age patients, 5 (62.5%) either enrolled or had received a recommendation to enroll in support services such as special education classes, resource assistance, homebound education services, vocational rehabilitation, occupational therapy, physical therapy, and speech therapy. Clinical observation, parent reports, and direct assessment also indicated that patients had difficulty with attention and concentration, inhibition, auditory learning, and socialization. Two patients who were of eligible age were not able to complete their high school education.

Table 2. Neurocognitive Evaluations of Children With Dysembryoplastic Neuroepithelial Tumorsa
Patient No.Age at Surgery, Years, MonthsEvaluationTime From Surgery, MonthsOverall Intellect (Standard Score)aReading (Standard Score)bSpelling (Standard Score)bMathematics (Standard Score)bVisual Motor IntegrationMemory (Standard Score)bProcessing Speed (Standard Score)bSupport ServicesParent-Reported Measures and Assessment Reportsc
  • NA, not available; ADHD, attention deficit hyperactivity disorder not otherwise specified; PT, physical therapy.

  • a

    Retrospective chart review of children diagnosed with dysembryoplastic neuroepithelial tumors between January 1988 and December 2007 at St. Jude Children's Research Hospital.

  • b

    Population mean = 100 (standard deviation, 15).

  • c

    Information derived from Behavioral Rating Inventory of Executive Function (BRIEF), the Child Behavior Checklist (CBCL), and assessment reports.

110.2110Average (NA)Average (97) Average (107) High average (119)Average (97)No 
25.115Average (94)      NoDifficulty with sustained  attention
  28       OccupationalDiagnosed with ADHD
  316Borderline (73) Average (NA)Borderline (NA)Low average (NA)  Occupational  SpeechPTDifficulties with impulsivity,  mental flexibility, and  auditory learning
415160 Deficient (55) Borderline (77)   Special educationUnable to graduate from  high school because  of learning disabilities
516.2120Low average (82)Average (110)Average (103)High average  (118) Deficient (68) NoAdjustment difficulties
6911Borderline (72)Borderline (78)Deficient (69)Deficient (58)Low average (88)Low average  (NA)Borderline  (72)Educational support  recommended 
  213Borderline (75)Deficient (58)Deficient (62)Low average (81)  Average  (96)Education support  recommendedDifficulties with social  competency
  324Borderline (79)Deficient (46)Deficient (69)Borderline (75)Average (105) Low average  (86)Special educationProblems with sustained  attentionReading-related learning disability
  463Average (90)Borderline (76)Borderline (73)Borderline (70)Average (97)Borderline (NA)Low average  (NA)Resource assistance  3 times/wk 
713.711 Average (102)Average (106)Low average (87)Average (90)   Significant problems with  sustained attention, socialization, and aggression
  275Low average (87)      Recommended for  vocational  rehabilitationDid not graduate from  high school.Behavioral misconduct and incarceration; reactive depression; alcohol and drug abuse
95.511Deficient (66)   Deficient (NA)Deficient (NA) Preschool ageAuditory processing and  memory for auditory input significantly deficient; receptive language deficiency Difficulties with sustained attention
106114High average (113)High average (114)Average (105)High average  (110)Average (92)Superior (NA) NoSlow psychomotor speed
  230Superior (123)High average (119)High average  (118)High average  (112)Average (98)  NoSlow psychomotor speed
  350High average (119)Average (108)Average (104)Average  (102)High average (117)  NoRecovery of visual motor skills
  469Superior (122)Very superior (133)High average  (119)High average  (116)High average (113)Very superior  (NA) No 
1111.616Low average (81)Deficient (64)Deficient (64)Borderline (71)Borderline (75)  Educational support recommendedDifficulty with sustained attention, concentration, and recall of verbally presented material
  221Average (90)Borderline (70)Deficient (61)Deficient (67) Average (NA) Special educationSocial withdrawal and anxiety
  342Low average (81)Deficient (69)Deficient (65)Deficient (61) Average (NA) Homebound–special educationVerbal skills deficit Visual-spatial skills deficitWeak self-esteem

DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES

We retrospectively analyzed clinical data, radiologic and pathologic characteristics, and neurocognitive test results of 11 patients diagnosed with DNET at SJCRH between January 1988 and December 2007. We believe the neurocognitive and neurologic findings of the current study were significant: 67% of tested patients had a visual field defect, which is higher than the rate of 5% to 18% reported previously.1-3

In the current study, only 3 patients had average or above-average cognitive function, and 5 of 8 (63%) of school-aged patients were receiving or were deemed eligible to receive special support services. These values are considerably higher than those reported previously. In 3 studies by Daumas-Duport et al, few tested patients were found to have a borderline IQ (ie, none of 14 patients,6 2 of 39 patients,1 and 6 of 20 patients2), but further details were not provided. Cognitive testing and academic achievement of patients with DNETs have also not been well documented in other studies.9-11 In their series, Nolan et al reported that 5 of 26 patients (19%) had a history of developmental delays or learning difficulties,12 but the details of the tests used to evaluate these 5 patients were not provided.

Comprehensive neurocognitive evaluation is not routinely reported in studies on children with DNETs and, when performed, usually includes only a small subset of the cohort study or data that are combined with that of adults. Minkin et al performed neurocognitive evaluation of 6 of 24 (25%) patients (5 with temporal tumors and 1 with a nontemporal tumor).13 Two patients with preoperative cognitive impairment remained impaired postoperatively. Hennessy et al performed neurocognitive evaluation of children and adults with different temporal lobe lesions (n = 282) who had persistent seizures (n = 56; 20%) after temporal resection.14 In their series, 10 of 77 patients with DNETs (13%) had persistent seizures and additional damage in the form of behavioral and/or cognitive disorders or GTC seizures, and spread abnormalities on electroencephalogram was evident in 6 of the 10 (60%) patients. No data were provided either with regard to the 67 patients with controlled seizures, the age of the patients, or details of the neurocognitive tests used. However, Raymond et al reported a detailed neurocognitive evaluation of 10 of 16 adults and children with DNETs.15 Memory was affected in 8 of 10 (80%) patients, and the mean verbal and performance IQ scores were 94.6% and 105%, respectively. There were 3 patients with developmental delays, of whom only 1 demonstrated some improvement in the postsurgical developmental follow-up.

To our knowledge, the current study is the first in children with DNETs in which comprehensive neurocognitive testing was performed in the majority of patients, and this may be the reason why our results of neurocognitive testing are different from those of previous studies. However, the current study is a retrospective study on a small group of patients, and testing methods varied with patient age at the time as well as the year of testing, which dictated the test version available. Moreover, factors such as use of antiseizure medications (AEDs), family environment, pre-existing conditions, or timing of evaluations may have affected the results.

Four patients in the current cohort were being treated with carbamazepine, and 1 patient was receiving phenytoin at the time of evaluation. Although a previous report in the literature has shown a relation between AEDs and cognition,16 many studies do not account for the confounding effects of factors such as type of seizures, age of the patient, length of exposure to medication, or the number of seizures.17, 18 In addition, results of large-scale studies have varied with the aspect of cognition being measured. For example, among children with seizures, children prescribed AEDs were found to score lower on processing speed, language, and verbal memory and learning than those not receiving medication. Children with a history of multiple seizures, even those not receiving medication, had lower scores on measures of attention and executive function compared with children who had only 1 seizure.19

In the current study, Patient 10 had high-achieving parents, which could be a family status-related variable that contributed to why he performed better than the average child, especially with regard to reading (Table 2). Patients 6 and 7 had pre-existing conditions such as congenital glaucoma and behavioral issues, which may have contributed to their poor performance. In addition, Patient 9 underwent a neuropsychological evaluation 1 month after surgery and had a borderline IQ score, suggesting that factors other than the tumor may influence cognition. Because of these reasons, it is impossible to determine the impact of DNETs alone, isolated from other factors, on cognition in this study or previous studies. Prospective large-scale studies are needed that include serial neurocognitive evaluations conducted at diagnosis, before surgery, after surgery, and during regularly scheduled follow-up.

Protocol-driven assessment of cognitive function can decrease variability in testing procedures and improve comprehension of disease-related and treatment-related impact on performance. Such assessments would also serve as an important conduit to identify patients in need of support services. For example, Patient 6 exhibited improvement in performance 5 years after surgery, which the clinician attributed to special educational support at school as well as continued resource assistance provided. Such services improved intellect level from the borderline to the average range and academic performance from the deficient to the borderline range. These gains may not have occurred without timely assessment, accurate diagnosis of function, and critical recommendations to the family and school.

Support services recommended by clinicians can vary depending on the area(s) of weakness exhibited in detailed testing. Methods used to intervene with otherwise healthy populations having similar deficits can provide a basis for formulating these recommendations. Intervention programs can include pharmacotherapy, cognitive therapy, experimental interventions designed relative to specific deficits, or commercially available programs. An accommodation approach could also be taken that improves the survivor's instructional environment at home or in school.20

The rates of disease recurrence and progression of DNETs in the current study were higher than those reported previously. Particularly, Patient 6 is to our knowledge only the second reported patient to have developed 2 recurrences after GTR.13 Initial studies on patients with DNETs did not identify risk factors for tumor recurrence because they did not find recurrent disease. In 5 studies reporting a total of 238 patients (some of whom were reported in >1 study), patients receiving adequate postoperative follow-up had no recurrent disease.1-3, 6, 7 However, later studies have reported tumor recurrence with incomplete resection in 1 of 52 patients (2%)16 and 3 of 26 patients (12%)10, 12 or after GTR in 1 of 14 patients (7%)5 and 1 of 24 patients (4%).13 Additional case studies have also been reported.21, 22 Ray et al22 reported 5 patients with recurrent DNET (3 adults and 2 children), with tumor recurrences developing in 2 patients after GTR. Ray et al provided a comprehensive review of 9 recurrent cases from the literature in their study.

We found no identified risk factors for DNET recurrence in our literature search. The majority of studies regarding DNETs appear to have focused on identifying risk factors for seizure control but not tumor control.9-14, 23 Our group of 4 patients who experienced disease recurrence and progression was too small to pinpoint histopathologic, radiologic, or clinical factors for tumor recurrence.

The time to disease progression or recurrence in the current series ranged from 2 to 12 years (median, 2.5 years). Ray et al reported a median time to disease recurrence of 6.8 years (range, 1-11 years) in 5 cases.22 Therefore, based on these data and those from the current study, we recommend annual surveillance for patients with DNETs. In patients who experience worsening seizures, imaging should be performed sooner. The wide range in time to diagnosis generally reflects the lack of standard recommendations for the best time for surgical intervention. Our cohort had a lower variance in median time from seizure than that reported in other studies (onset to surgery, 3.5 years; range, 0.5-24 years). In guidelines developed by O'Brien et al for the diagnosis and management of DNETs, 2 years is recommended as the standard time to medically control seizures.24 In addition, they accept management with observation only in patients with stable seizures.

The results of the current study dispute the common observations with respect to risk of disease recurrence and neurocognitive testing in children with DNETs. Although the current study was limited by a small patient population and its retrospective nature, the results support the need for a registry that will facilitate prospective studies in patients with DNETs.

Acknowledgements

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES

We thank Rupinder Chera, Vivian Tsung, Anthony Griffin, Uri Edell, Peter Chung, and David Hodgson.

REFERENCES

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. CONFLICT OF INTEREST DISCLOSURES
  8. REFERENCES
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