Neurological disease in a child: CNS tumours Flashcards
Define CNS tumours.
Brain tumours in children are almost always primary rather than metastatic (contrast to adults) and 60% are infratentorial (located below the tentorium and cerebelli). They are the most common solid tumour in children and are the leading cause of childhood cancer deaths in the UK.
Explain the aetiology of CNS tumours.
Most brain tumors in children are sporadic, that is to say they arise with no discernable familial or environmental cause.
What are different types of CNS tumours?
Astrocytoma (~40%)
Medulloblastoma (~20%)
Ependymoma (~8%)
Brainstem glioma (6%)
Craniopharyngioma (4%)
Atypical teratoid/rhabdoid tumour
What is an astrocytoma?
Varies from benign to highly malignant (glioblastoma multiforme).
What is a medulloblastoma?
Arises in the midline of the posterior fossa.
May seed through the CNS via the CSF and up to 20% have spinal metastases at diagnosis.
What is an ependymoma?
Mostly in posterior fossa where it behaves like medulloblastoma.
What is a brainstem glioma?
Malignant tumours associated with a very poor prognosis.
What is a craniopharyngioma?
A developmental tumour arising from the squamous remnant of Rathke pouch. It is not truly malignant but is locally invasive and grows slowly in the suprasellar region.
What is an atypical teratoid/rhabdoid tumour?
A rare type of aggressive tumour that most commonly occurs in young children.
What are signs and symptoms of a CNS tumour?
The developmental age of the child is important as presentation varies according to age and their ability to report symptoms. Signs and symptoms are often related to evidence of raised ICP but focal neurological signs may be detected depending on site of the tumour.
Papilloedema may be present, but can be a late sign and difficult to detect.
Spinal tumours, primary or metastatic, can present with back pain, peripheral weakness of arms or legs, or bladder/bowel dysfunction, depending on the level of the lesion.
What are appropriate investigations for CNS tumours?
Brain tumours are best characterised on MRI scan. Magnetic resonance spectroscopy can be used to examine the biological activity of a tumour. Some tumour types can metastasize within the CSF and a lumbar puncture is therefore required for complete staging of the disease.
Lumbar puncture must not be performed without neurosurgical advice if there is any suspicion of raised intracranial pressure.
What is the management for CNS tumours?
Surgery is usually the first treatment and is aimed at treating hydrocephalus, providing a tissue diagnosis and attempting maximum resection. In some cases the anatomical position of the tumour means biopsy is not safe, e.g. tumours in the brainstem and optic pathway.
Even tumours which are histologically ‘benign’ can threaten survival. The use of radiotherapy and/or chemotherapy varies with tumour type and the age of the patient.
What are complications associated with CNS tumours?
The functional implications of the site of the tumour, the potential hazards of surgery and the importance of radiotherapy in treatment all combine to place children with brain tumours at particular risk of neurological disability and of growth, endocrine, neuropsychological, and educational problems.
Survivors may present complex combinations of these problems.
What is the prognosis of CNS tumours?
Earlier diagnosis of brain tumours in children and young adults improves long-term outcomes. Resection of the tumour may resolve seizures and headaches. The surgical mortality is 1% for a paediatric craniotomy.
The morbidity is higher and depends on the child’s condition pre-operatively.
Tumours of the brain and CNS are the most common cause of deaths from cancer in childhood, accounting for around a third of all cancer deaths in children.
