Radiological classification of optic pathway gliomas: experience of a modified functional classification system

Optic pathway gliomas (OPGs) in childhood are associated with neurofibromatosis type 1 (NF1) and since 1958 have been classified anatomically using the Dodge classification (DC). MR scanning permits a more detailed anatomical description than can be classified by this historical system. A modified Dodge classification (MDC) has been applied to MRI scans from a cohort of 72 patients (36.1% NF1-positive) from 4 centres participating in an international clinical trial. The MDC was feasible, applicable and more detailed than the original DC. NF1-positive cases more commonly involved both optic nerves (p = 0.021) and other multiple locations (p = 0.001). NF1-negative tumours more commonly involved the central chiasm (p = 0.005) and hypothalamus (p = 0.003). Fewer hypothalamus-positive tumours were associated with optic nerve involvement (p = 0.009), whereas more were associated with central chiasm involvement (p<0.001). From diagnosis to follow-up, there was concordance between DC and MDC in 51/72 cases (70.8%). The MDC is therefore proposed for use in clinical trials of new treatments for OPGs.

Intrathecal chemotherapy delivered by a lumbar-thecal catheter in metastatic medulloblastoma: a case illustration

BACKGROUND

Medulloblastoma is the most common malignant brain tumour in children. Despite recent advances, the prognosis in high risk patients remains poor. Further improvement in survival is dependent upon the development of strategies to attack the tumour more effectively, but with less toxicity. Intrathecal chemotherapy, is an ideal but currently underused method of directly targeting residual tumour within the area of resection and the leptomeningeal disease commonly associated with this tumour.

METHOD

We describe the case of a 12 yr old child with metastatic medulloblastoma, who received intrathecal topotecan via a spinal catheter.

CONCLUSION

This method represents a simple, safe and effective method of delivering an even and widespread distribution of drug within the cerebrospinal fluid (CSF) of the neuroaxis. With new agents being identified and others in the early stages of development, intrathecal chemotherapy may emerge as an important therapeutic option to consider when faced with such challenging cases.

Relative shortening and functional tethering of spinal cord in adolescent scoliosis - Result of asynchronous neuro-osseous growth, summary of an electronic focus group debate of the IBSE

There is no generally accepted scientific theory for the causes of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The Statement for this debate was written by Dr WCW Chu and colleagues who examine the spinal cord to vertebral growth interaction during adolescence in scoliosis. Using the multi-planar reconstruction technique of magnetic resonance imaging they investigated the relative length of spinal cord to vertebral column including ratios in 28 girls with AIS (mainly thoracic or double major curves) and 14 age-matched normal girls. Also evaluated were cerebellar tonsillar position, somatosensory evoked potentials (SSEPs), and clinical neurological examination. In severe AIS compared with normal controls, the vertebral column is significantly longer without detectable spinal cord lengthening. They speculate that anterior spinal column overgrowth relative to a normal length spinal cord exerts a stretching tethering force between the two ends, cranially and caudally leading to the initiation and progression of thoracic AIS. They support and develop the Roth-Porter concept of uncoupled neuro-osseous growth in the pathogenesis of AIS which now they prefer to term 'asynchronous neuro-osseous growth'. Morphological evidence about the curve apex suggests that the spinal cord is also affected, and a 'double pathology' is suggested. AIS is viewed as a disorder with a wide spectrum and a common neuroanatomical abnormality namely, a spinal cord of normal length but short relative to an abnormally lengthened anterior vertebral column. Neuroanatomical changes and/or abnormal neural function may be expressed only in severe cases. This asynchronous neuro-osseous growth concept is regarded as one component of a larger concept. The other component relates to the brain and cranium of AIS subjects because abnormalities have been found in brain (infratentorial and supratentorial) and skull (vault and base). The possible relevance of systemic melatonin-signaling pathway dysfunction, platelet calmodulin levels and putative vertebral vascular biology to the asynchronous neuro-osseous growth concept is discussed. A biomechanical model to test the spinal component of the concept is in hand. There is no published research on the biomechanical properties of the spinal cord for scoliosis specimens. Such research on normal spinal cords includes movements (kinematics), stress-strain responses to uniaxial loading, and anterior forces created by the stretched cord in forward flexion that may alter sagittal spinal shape during adolescent growth. The asynchronous neuro-osseous growth concept for the spine evokes controversy. Dr Chu and colleagues respond to five other concepts of pathogenesis for AIS and suggest that relative anterior spinal overgrowth and biomechanical growth modulation may also contribute to AIS pathogenesis.

Phase II study of the combination of cisplatin + temozolomide in malignant glial tumours in children and adolescents at diagnosis or in relapse (cistem2/nct00147160)

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Background: Temozolomide has been shown moderately effective in pediatric high-grade glioma (HGG). By decreasing the activity of MGMT, principal mechanism of resistance to temozolomide, cisplatin may increase the activity of this alkylating agent. Methods: Patients aged 4 to 21y with HGG outside the brainstem were treated at diagnosis or at relapse every 28 days with a combination of cisplatin 80 mg/m2 intravenously on day-1 and temozolomide 200 mg/m2 orally on days 2–6, according to the pediatric phase I recommendations. Patients treated at diagnosis had to proceed to involved field radiotherapy after the chemotherapy window. According to initial response, patients were offered additional courses, up to seven. We considered that this combination would be of interest if the response rate was superior or equal to 20%, using a two-stage Simon design in 3 cohorts: evaluable non measurable (infiltrative) at diagnosis (cohort A1); measurable disease (nodular) at diagnosis (A2); recurrent disease (B). The primary endpoint was complete or partial response after two courses, confirmed by central review. Up to 29 evaluable pts were to be entered in each cohort. If fewer than 4/29 responses were observed, it would be concluded that the combination is ineffective. Results: 56 pts were entered from 10/2003 through 07/2006 in 25 centers. One was excluded after central pathology review and 3 due to insufficient radiology work-out. 42 had grade III and 13 grade IV gliomas, including 21 tumors with oligodendroglial features. No response was observed in the first 11 pts in cohort A1 and in the first 12 pts in cohort B. Two partial and 4 minor responses were confirmed in 29 pts of cohort A2 leading to a 7% response rate (95% CI, 1–23%). Median time to progression was 1.7, 7.1 and 6.9 months in cohorts A1, A2 and B, respectively. Toxicity was manageable except in pts with large infiltrative lesions who did not tolerate hydration. Conclusion: CISTEM combination has insufficient efficacy in pediatric compared to adult HGG despite efficient down-regulation of MGMT activity. To overcome resistance to temozolomide in children and adolescents, one may need to target other known resistance mechanisms such as mismatch-repair deficiency.

[Table: see text]

Shaken baby syndrome

Before the Court of Appeal

Acute bilateral striatal necrosis with rotavirus gastroenteritis and inborn metabolic predisposition

We present a 9-month-old male with acute rotavirus gastroenteritis who developed an acute encephalopathy with focal seizures and developmental regression. Magnetic resonance imaging showed bilateral striatal necrosis and raised glutarylcarnitine levels on tandem mass spectrometry of a (crisis) blood spot, and chromatography of organic acids revealed increased urinary excretion of dicarboxylic acid. Skin biopsy demonstrated a partial decrease in glutaryl-CoA dehydrogenase activity. The case was not typical for either rotavirus encephalitis/rotavirus-associated encephalopathy or for glutaric aciduria type I. The patient has developmental delay and continues to receive physiotherapy, speech therapy, and local developmental follow-up.

The 'unified hypothesis' of Geddes et al. is not supported by the data

Inflicted head injury to the developing brain frequently results in serious disability. The pathogenesis of the neuraxial and ocular findings in infants believed to have suffered inflicted head injury remains the subject of considerable debate. Recent neuropathology studies of fatal cases of inflicted head injury and of a foetal/perinatal non-traumatic model have led to the proposal that there is a 'unified hypothesis', the essential feature of which is hypoxic brain swelling secondary to cervicomedullary injury. It has been suggested that less than violent forces may be involved and even that some cases may not be due to trauma at all. The purpose of this paper is to provide a critical review of the data upon which these suppositions are based on a background of what is already known. It is submitted that there are serious flaws in the methodology; the conclusions reached cannot logically be drawn from the data; and the 'unified hypothesis' is not supported by the evidence. On the basis of the data presented, it is also difficult to sustain the secondary hypothesis purporting to describe a minority cohort with 'infantile encephalopathy with subdural and retinal bleeding' of non-traumatic causation.

Acute bilateral thalamic necrosis in a child with Mycoplasma pneumoniae

A previously neurodevelopmentally intact 5-year-old male was admitted to hospital with a right lower lobe pneumonia with pleural effusion, subsequently confirmed to be a Mycoplasma pneumoniae infection. On the seventh day of the illness he had a prolonged generalized tonic or tonic-clonic convulsion, requiring intubation and ventilation. He was slow to regain consciousness (Child's Glasgow Coma Score 7-10 over 6 days) and brain imaging with CT and then MRI demonstrated bilateral thalamic lesions with oedema and central haemorrhage suggestive of acute bilateral thalamic necrosis, without striatal or white-matter involvement. He was treated with a 2-week course of erythromycin, and as an autoimmune process was considered possible, 5 days of intravenous methylprednisolone (20 mg/kg/day) followed by a 4-week oral prednisolone taper. He made a slow recovery over the next few weeks with almost complete neurological recovery by 2 months but with significant dysarthria, drooling, and a mild left hemiparesis. At 9 months, significant dystonia continued to affect his speech and, together with tremor, his upper-limb fine motor function bilaterally. His gait, personality, and higher cognitive functions appeared to have recovered fully. Although acute striatal necrosis, acute disseminated encephalomyelitis, and encephalitis have been reported with Mycoplasma pneumoniae and a similar picture of acute bilateral thalamic necrosis with influenza-A ('acute necrotizing encephalopathy'), this is the first reported case of Mycoplasma pneumoniae-associated isolated acute bilateral thalamic necrosis.

Intradural cerebellar chordoma in a child: a case report and review of the literature

CASE REPORT

The authors describe an unusual case of an intradural cerebellar chordoma, the first such case to be reported in a child. A 9-year-old girl presented with headaches and papilloedema, and a discrete cerebellar mass was resected, which was shown histologically to be chordoma. There was no bony or dural association, and after radiologically proven complete resection it was elected that the child be followed expectantly.

DISCUSSION

The case is compared with the few previously reported intradural chordomas, and insights into the origins and management of such cases are discussed.

Neuroimaging for non-accidental head injury in childhood: a proposed protocol

Non-accidental head injury (NAHI) is a major cause of neurological disability and death during infancy. Radiological imaging plays a crucial role in evaluating craniospinal injury, both for guiding medical management and the forensic aspects of abusive trauma. The damage sustained is varied, complex and may be accompanied by an evolving pattern of brain injury secondary to a cascade of metabolic and physiological derangements. Regrettably, many cases are poorly or incompletely evaluated leading to diagnostic errors and difficulties in executing subsequent child care or criminal proceedings. It is evident, from cases referred to the authors, that imaging protocols for NAHI are lacking (or only loosely adhered to, if present) in many centres throughout the U.K. Future research in this field will also be hampered if there is a lack of consistent and reliable radiological data. There is no nationally agreed protocol for imaging NAHI. We propose such a protocol, based upon a wide experience in the medical management of child abuse and extensive involvement in the medicolegal aspects of NAHI.

Temozolomide in malignant gliomas of childhood: a United Kingdom Children's Cancer Study Group and French Society for Pediatric Oncology Intergroup Study

PURPOSE

To determine the response rate of the malignant gliomas of childhood to an oral, daily schedule of temozolomide.

PATIENTS AND METHODS

A multicenter, phase II evaluation of an oral, daily schedule of temozolomide (200 mg/m(2) on 5 consecutive days) was undertaken in children with relapsed or progressive, biopsy-proven, high-grade glioma (arm A) and progressive, diffuse, intrinsic brainstem glioma (arm B). Evidence of activity was defined by radiologic evidence of a sustained reduction in tumor size on serial magnetic resonance imaging scans.

RESULTS

Fifty-five patients were recruited (34 to arm A and 21 to arm B) and received 215 cycles of chemotherapy. Grade 3/4 thrombocytopenia was the most frequent toxic event (7% of cycles). Prolonged myelosuppression resulted in significant treatment delays and dose reductions (17% and 22% of cycles, respectively). Two toxic deaths were documented and were related to myelosuppression and sepsis in one patient and pneumonia in a second. The overall (best) response rate was 12% for arm A (95% confidence interval [CI], 3 to 28 in the study cohort, and 2 to 31 for eligible patients) and 5% and 6%, respectively, for arm B (95% CI, 0 to 26 in the study cohort, and 0 to 27 for eligible patients). Stabilization of disease was also documented and was most noteworthy for brainstem gliomas, where two patients achieved both radiologic static disease and discontinued steroid medication.

CONCLUSION

Despite moderate toxicity, objective response rates to temozolomide have been low, indicating that temozolomide has minimal activity in the high-grade gliomas of childhood.

Treatment of Chiari malformation, syringomyelia and hydrocephalus by neuroendoscopic third ventriculostomy

This short paper illustrates a case with cervical myelomeningocoele, a Chiari malformation (CM), hydrocephalus (HC) and cervical syringomyelia treated by neuroendoscopic third ventriculostomy (NTV) with resolution of both the hydrocephalus and the syrinx. Two similar cases are discussed. The technique is advocated for the treatment of such complex dysraphic conditions.

The use of chemotherapy to facilitate surgical resection in pleomorphic xanthoastrocytoma: experience in a single case

The use of noncytotoxic chemotherapy as an adjuvant treatment to permit resection of a pleomorphic xanthoastrocytoma (PXA) is described. A 6-year-old girl with a large right occipito-temporo-parietal lesion presented with signs and symptoms of raised intracranial pressure. An initial attempt at resection was halted because of excessive blood loss, and tumour embolisation was not feasible as no suitable vascular pedicle was identified. Two cycles of vincristine and carboplatin were given, and these decreased the vascularity of the tumour allowing subsequent complete macroscopic resection 9 weeks later. The use of chemotherapy to decrease the vascularity of the tumour by way of its antiangiogenic effects is discussed.

Third ventricular plasma-cell lesion with delayed intraventricular transudation of contrast medium

We report a patient presenting with hydrocephalus secondary to a posterior third ventricular plasma-cell lesion which exhibited delayed transudation of contrast medium into the adjacent aqueduct and fourth ventricle.

High resolution CISS imaging of the spine

Spatial resolution remains one of the major problems and goals in spinal imaging. The high spatial resolution afforded by a novel sequence, constructive interference in steady state (CISS), provides a further refinement to MRI, the modality of choice in the investigation of suspected intraspinal pathology. Both complex and subtle abnormalities are more fully elucidated using CISS. It is now used in our institution as an adjunct to conventional imaging sequences in the diagnostic evaluation of complex intraspinal pathology. The anatomical information provided by CISS is of particular value in planning surgical interventions, most notably in the management of intraaxial and extraaxial cystic abnormalities, dysraphic malformations and disturbances of cerebrospinal fluid circulation, including post-traumatic and post-surgical scarring.

Ventricular enlargement in multiple sclerosis: a comparison of three-dimensional and linear MRI estimates

Atrophy of central white matter is related to irreversible clinical disability in multiple sclerosis (MS) and ventricular enlargement may be a sensitive marker of this tissue loss. Therapeutic trials in MS have provided MRI data for investigation of cerebral atrophy in MS. These studies use almost exclusively two-dimensional (2-D) images, which may be limited in the assessment of three-dimensional (3-D) structures. We used 3-D MRI data to estimate ventricular volumes in 40 patients with MS and 10 healthy controls, to look at associations with clinical disability and the stage of the disease. We then compared simple linear measures of ventricular size from conventional 2-D images, with 3-D volume estimates to establish the best available linear indices of ventricular volume. Mean ventricular volumes were increased in the patients and significantly larger in the more disabled patients. The estimated volume of the third ventricle obtained from 3-D MRI showed the strongest association with the clinical stage of the disease, duration of symptoms and levels of disability. Finally, we confirmed that in patients with MS accurate data on ventricular size can be obtained from 2-D images by two simple and convenient linear measures, the width of the third ventricle and of the anterior horn of the lateral ventricle.

Brain stem compression by a giant vertebrobasilar aneurysm mimicking seronegative myasthenia

A patient is described with a vertebrobasilar aneurysm who was erroneously thought to have myasthenia gravis on the basis of the clinical presentation and investigations, which were interpreted as supportive of a disorder of the neuromuscular junction. Despite the correct diagnosis being made at a late stage the patient made a full recovery after radiological intervention.

Neuroendoscopic third ventriculostomy in dysmorphic brains

Neuroendoscopic third ventriculostomy (NTV) has superseded shunting as the treatment of choice in non-communicating hydrocephalus. Intracranial developmental anomalies have been considered to be relative contraindications for this procedure. We present one patient with a Dandy-Walker malformation and another with septo-optic dysplasia who presented with hydrocephalus. An NTV was performed successfully in both patients using a flexible neuroendoscope and utilising transendoscopic Doppler ultrasound to ensure a safe target area for ventriculostomy.