558 Arch Dis Child 1999;80:558–564 CURRENT TOPIC Arch Dis Child: first published as 10.1136/adc.80.6.558 on 1 June 1999. Downloaded from Clinical management of brain stem glioma David A Walker, Jonathan A G Punt, Michael Sokal Brain and spinal tumours in childhood (0–15 a brain stem tumour in a child very simple as years) account for 20–25% of childhood long as the need for such imaging is identified cancer, aVecting one in 2500 children. In the by correct attention to the presenting clinical UK, this means that about 350 new cases are features. Diagnosis by MRI gives clear defini- diagnosed each year, of which 55% and 50% tion of the site, extent and direction of growth, survive five and 10 years, respectively.1 For as well as the nature of the tumour—for exam- those who are survivors, about 60% have cog- ple, focal, diVuse, solid, or cystic (fig 1B and nitive deficits and 20–30% have diYculties C).6 with mobility and chronic pain.2 Deaths from Symptoms at presentation relate to the level this group of tumours in England and Wales of the lesion in the brain stem (midbrain, pons, account for the loss of over 10 000 life years or medulla) and the rate and direction of each year (C Stiller, personal communication, growth of the tumour. Late diagnosis by a gen- 1995).1 eral practitioner, paediatrician, or other spe- Within the group of brain and spinal cialist may be a problem if there is a lack of tumours there are a number of well defined appreciation of the importance of symptoms categories with characteristic clinical presenta- and signs,78and can lead to enhanced distress tions, biological behaviour, and suitability for for the child and parents. specific treatment approaches. These factors Most cases of posterior cranial fossa tumour combine to predict a range of outcomes from in children present predominantly with fea- the highly curable tumours (> 80% 10 year tures of raised intracranial pressure, and focal survival rate) such as germinoma and cerebel- neurological symptoms take second place. lar astrocytoma, through to the virtually incur- However, in most cases of brain stem glioma able brain stem glioma.1 Age at presentation is the converse applies. Common presenting http://adc.bmj.com/ also a crucial factor aVecting both prognosis symptoms are those of cranial nerve dysfunc- and treatment selection, especially for those tion producing any or all of the following: eye who develop tumours early in life before the movement disturbance, diplopia, facial weak- 3 brain has completed growth and development. ness, facial sensory loss, dysphagia, and Brain stem gliomas account for about 10% dysarthria.9 These might initially suggest dis- 1 of all brain and spinal tumours. The selection turbance of a single cranial nerve and lead to an of brain stem glioma for this article was erroneous diagnosis such as benign squint, prompted by diYculties surrounding its clini- Bell’s palsy, or other postviral syndromes. The on October 1, 2021 by guest. Protected copyright. cal diagnosis, both professional and lay uncer- appearance of such symptoms without obvious tainty about optimal surgical management, cause should always be taken seriously and be ineVectiveness of non-surgical treatment, clini- pursued by referral to a paediatric neurologist cal diYculties with good palliative care, and a or paediatric neurosurgeon, or by definitive historical lack of clear guidance about optimal investigation using MRI. referral patterns to children’s cancer centres, Other symptoms might include weakness where appropriate resources have already been and/or ataxia of one or more limbs signifying centralised for children’s cancers of other 45 involvement of the corticospinal pathways and organs. We define the brain stem as extend- cerebellar connections, respectively. Headache ing from the midbrain (tectal plate) to the and vomiting can occur, although clinically medullary cervical junction (fig 1A). There- raised intracranial pressure and papilloedema fore, brain stem glioma is a term describing a Faculty of Medicine are relatively unusual, except in later stages of and Health Sciences, collection of anatomically related tumours with disease progression. A fluctuating course is Academic Division of characteristic appearances on computed tom- common and can give rise to confusion with Child Health, Floor E, ography (CT) and magnetic resonance imag- inflammatory pathologies.10 Similarly, changes East Block, Queen’s ing (MRI) scans. Because they are frequently Medical Centre, in mood and behaviour recognised by the fam- not biopsied, “glioma” is used as a “catch all” ily are common and can precede more obvious Nottingham NG7 2UH, term unless a histological diagnosis has been UK neurological features. It is not uncommon for D A Walker made. these to be attributed to life events, which can J A G Punt distract the family and doctors from the more M Sokal Establishing the diagnosis specific symptoms when they develop. More Correspondence to: The ready availability of modern neuroimaging prolonged histories (several weeks to several Dr D A Walker. makes confirmation of the clinical diagnosis of months) indicate slower growing tumours. Clinical management of brain stem glioma 559 A unexplained vomiting, may be mistaken for a gastrointestinal or nutritional problem. The motor symptoms can then be regarded incor- Arch Dis Child: first published as 10.1136/adc.80.6.558 on 1 June 1999. Downloaded from rectly as developmental delay secondary to the poor state of nutrition and a further delay in diagnosis follows. The exceptions to the above patterns of presentation are tumours of the tectal plate of MB the midbrain and dorsally exophytic growths of the medulla, both of which produce raised intracranial pressure caused by hydrocephalus P as the major symptom. MD NEUROFIBROMATOSIS TYPE 1 Patients with neurofibromatosis type 1 (NF-1) have a predisposition to develop astrocytic C/MD tumours, which most commonly occur in the region of the hypothalamus/optic chiasm. They can also occur, less frequently, in the brain stem.11 They can be confused with unidentified bright objects on MRI, which can enlarge and recede during childhood and adolescence. Treatment with radiotherapy may be associ- ated with enhanced neurotoxicity. A cautious approach is recommended, reserving radio- therapy for patients with troublesome symp- toms that are clearly linked to tumour progression.12 13 The role of surgery GENERAL As with all central nervous system tumours in childhood the role of surgery is directed at the control of raised intracranial pressure, the pro- vision of tissue for accurate histological diagno- sis, and the physical reduction of tumour burden with the intention of improving focal neurological dysfunction. The actual role of surgery relates to the site of the lesion and its http://adc.bmj.com/ gross morphological characteristics as judged on MRI. Detailed gross morphological classifi- cation of brain stem tumours is now possible with both CT14 and MRI.615Subgroups identi- fied by site and imaging characteristics require specific management (table 1; fig 1). Whenever tumour debulking is being considered the neu- rosurgeon needs to consider the risks and ben- on October 1, 2021 by guest. Protected copyright. efits as regards operative mortality and worsen- ing neurological disability. MIDBRAIN TUMOURS Focal tumours of the tectal plate are often small and produce hydrocephalus with or without midbrain eye signs. They are usually low grade astrocytomas and surgery is re- Figure 1 (A) Line drawing stricted to control of the hydrocephalus, of brain stem showing the ventricular system as the preferably by neuroendoscopic third ventricu- shaded area, the boundaries of lostomy,17 rather than by insertion of a the midbrain (MB), pons (P), ventricular shunt, to avoid the morbidity asso- medulla (MD), and 18 cervicomedullary junction ciated with the latter. Although typically (C/MD). (B) Magnetic indolent,19 careful follow up with annual MRI resonance imaging (MRI) is required because a number will progress,20 at scan showing transverse view of diVuse pontine glioma. (C) which time open surgery to establish a firm MRI scan showing saggital diagnosis and to reduce tumour bulk is view of focal pontine glioma. indicated. The occasional tumour will be large at pres- Faster growing tumours can precipitate dra- entation, spanning the pineal region and matic neurological deterioration over a few midbrain. Estimation of serum concentrations days to weeks. In younger children (< 3 years of á fetoprotein, â human chorionic gonado- old) failure to thrive, often associated with trophin, and placental alkaline phosphatase 560 Walker, Punt, Sokal Table 1 Consensus for surgical management of brain stem tumours (UK paediatric DORSALLY EXOPHYTIC TUMOURS neurosurgical group)16 These are low grade astrocytomas or ganglio- gliomas that have grown out of the brain stem Arch Dis Child: first published as 10.1136/adc.80.6.558 on 1 June 1999. Downloaded from Anatomical site/ imaging characterisitics Probable pathology Surgical management into the fourth ventricle. The symptoms are slowly progressive and usually include features Midbrain Tectal plate Low grade astocytoma, exclude Observe/cerebrospinal fluid diversion of raised intracranial pressure. Partial resection non-germinomatous germ cell if necessary, consider debulking if is indicated and long term remission without tumours by measuring tumour tumour progresses the need for adjuvant treatment is the rule.20 22 markers Other As for Pons As for Pons Pons CERVICO-MEDULLARY TUMOURS DiVuse High grade astrocytoma No biopsy proceed to radiotherapy These are essentially very rostral intrinsic Focal solid/cystic Low/high grade astrocytoma Drain cysts/debulk solid component DXT depending upon severity of spinal cord tumours and are amenable to radi- neurological signs cal resection.29 Exophytic Low/high grade astrocytoma Debulk Medulla As for Pons Neurological, results of surgery poor Cervico-medullary Low grade astrocytoma Radical removal The role of radiotherapy Most brain stem gliomas transiently respond to DXT, dual x ray therapy.