According to the German Register of Cancer in Children, brain tumours represent ca. 20% of all cancers in children and adolescents, thus being the most common solid tumours in this age group. Only leukaemia and other haematological disorders have higher incidence. There are an estimated 300 to 350 new cases of brain tumours in children every year in Germany.
The most common types are astrocytomas (ca. 40%), medulloblastomas (ca. 20%) and ependymomas (ca. 10%). Other, less common types include PNET (primitive neuroectodermal tumours), craniopharyngiomas, gangliogliomas, plexus tumours, pineal tumours, germ cell tumours and meningiomas.
The most common symptoms of brain tumour in children are headaches, nausea and vomiting, disturbed sense of balance, vertigo, disturbances in eye movement, fatigue, and drowsiness. Less common or occurring at later stages are: disturbances in coordination, paralysis, visual disturbances, hearing loss, and wryneck (torticollis).
The aetiology of brain tumours in children is not well known. There are no generally accepted risk factors, but it is known that in some diseases the risk of brain tumour development is elevated. Examples of the latter disorders include neurofibromatosis and von Hippel–Lindau disease. In most cases however no predisposing disease can be found.
Diagnosis consists of clinical examination followed by imaging tests of the head. The method of choice here is magnetic resonance imaging (MRI). Additional tests (such as CT scans, MRI of spinal column, ophthalmological or laryngological examination, CSF examination, angiography, blood tests, electrophysiological examination) are in most cases not necessary.
Fig. 1: T1-weighted MRI scan with contrast agent of brain tumours (arrow)
A: optic nerve glioma
B: Pilocytic astrocytoma of the brain stem
In most cases of brain tumours in children surgical treatment is the first-line option. In the case of benign tumours, their removal can lead to full recovery. If complete removal cannot be achieved, regular MRI check-ups are required to assess the growth rate of the tumour. If remaining tumour fragments do exhibit a tendency to grow back adjuvant therapies (radiotherapy and/or chemotherapy) can be considered. Malignant tumours always require radiotherapy and/or chemotherapy following the surgery, even if postoperative MRI scans show no remnants of the tumour. However, radiotherapy should not be used in children under the age of 3, since long-term toxicity of radiotherapy poses too much of a risk for the developing brain. Therefore in small children only chemotherapy is used. In cases of highly malignant tumours chemotherapy preceding surgery may be useful. In the case of inoperable tumours tissue samples of the tumour are taken to determine its type and plan suitable treatment.
Pilocytic astrocytomas are benign, slowly growing tumours, often situated in the cerebellum, characterised by good delineation from surrounding tissue. In MRI they are visible mostly as cystic lesions, taking up contrast agent. Surgery is the first-line treatment. In most cases complete removal of the tumour is possible with full recovery. Recurrences are rare.
A and B: MRI of a 16-year-old girl with a pilocytic astrocytoma in the cerebellum. The patient complained of headaches and disturbances in the sense of balance.
C and D: MRI 2 years after the surgery showing complete removal of the tumour. The patient had fully recovered, and displayed no neurological deficits.
A and B: MRI of a 4-year-old girl with pilocytic astrocytoma in the middle axis of the brain (thalamus, third ventricle). The first symptoms included disturbances in the sense of balance.
C and D: Postoperative MRI scan showing complete removal of the tumour. Slight gait disturbance was the only remaining neurological deficit.
A and B: MRI of 14-year-old boy with pilocytic astrocytoma of the right temporal lobe. The patient complained of headache, nausea and vomiting.
C and D: MRI taken 4 years after the surgery showing complete tumour removal. The patient remains symptom-free.
It is a special type of pilocytic astrocytoma growing along the optic nerves or optic pathways, often also affecting the midbrain (hypothalamus). The most common symptoms include visual disturbances and hormonal disorders. Since the course of the disease is very hard to predict there are no unified treatment algorithms. Spontaneous remissions are possible (see Fig. 5). If mass effect occurs partial removal of the tumour is a viable option. Complete removal is rarely indicated due to the risk of severe hypothalamic complications. In the case of tumours limited to the eye socket, division of the optic nerve in its pre¬chiasmatic part can be undertaken to stop the tumour from spreading to the other side.
A: MRI of a 2-year-old girl with a large glioma of the optic nerve, optic chiasm and pathway. The patient displayed at first only a tendency to stumbling and falling down, as well as a preference to use her left hand. Due to the extent of the tumour resection could not be performed, but a tissue sample has been collected.
B: Control MRI scan taken 6 months later showed surprisingly spontaneous remission of the tumour. After 2 years the tumour remains stable, with no tendency to grow.
A: MRI of a 3-year-old boy with a partially cystic glioma of the optic nerve, compressing the brain stem. The boy displayed at first inflammation of the eye socket (orbitaphlegmone). The tumour was discovered by chance.
B: Tumour under a brain artery (arrow).
C: After the surgery the brain stem and basilar artery remain free (arrow).
D: MRI scan taken 3 months after the surgery showing removal of a significant portion of the tumour. The part of the tumour affecting the hypothalamus was left in situ to avoid complications. The patient shows no neurological or hormonal deficits.
Ependymomas arise from the lining of the ventricles of the brain and spinal tap (ependyma). Due to their location they often lead to accumulation of the cerebrospinal fluid. Surgery is the first-line treatment option. Ependymomas are in most cases relatively easy to separate from the healthy brain tissues, which is helpful for the surgeons. Only in the case of malignant tumours or inoperable remnants of the tumours can radiotherapy be used.
A and B: MRI of an 18-year-old boy with an ependymoma of the rhomboid fossa (arrow). Clinical symptoms included headache, nausea and vomiting.
C: Tumour (arrow) below the cerebellar tonsils.
D and E: MRI image taken 4 years after the surgery showing complete tumour removal with no signs of recurrence. The patient is symptom free.
A: MRI of a 16-year-old boy with ependymoma of the upper part of the cervical spinal cord (arrow). The initial clinical symptoms were pain in the neck and vomiting. In spite of the unfavourable location of the tumour (danger of tetraplegia) surgery is the first-line treatment option.
B: Arrows point to the remaining thin layer of spinal cord tissue (grey margin around the lighter tumour tissue)
C: Monitoring of the motor evoked potentials.
D and E: Follow-up MRI 3 months after the surgery showing complete tumour removal. Apart from slight motor impairment of his right hand the patient is symptom-free.
Craniopharyngiomas are benign tumours derived from embryonic tissue (remnants of the Rathke pouch), originating commonly from the pituitary stalk (infundibulum). They are typically slow growing tumours and cause clinical symptoms due to the compression of surrounding structures. In cases of wider extension of the tumour, with obliteration of the 3rd brain ventricle, accumulation of cerebrospinal fluid may arise with hydrocephalus. Visual disturbances are common due to compression of the optic nerves. Untreated they lead to blindness. Later hormonal disturbances develop.
A: MRI of a 13-year-old girl with a large cystic craniopharyngioma. Visual disturbances were the first clinical symptoms.
B: The tumour was strongly compressing and flattening the optic nerves (arrow points to the right optic nerve on the tumour capsule).
C: Operative field after complete tumour removal.
D: Follow-up MRI showing complete tumour removal. Visual function could be preserved.
Medulloblastomas are malignant tumours (WHO grade 4), mostly originating from the vermis cerebelli. They tend to metastasize into the cerebrospinal fluid space. Surgery is always followed by postoperative radiotherapy and/or chemotherapy.
A: MRI of a 6-year-old boy with a large medulloblastoma. The first symptom was vomiting.
B: Postoperative follow-up MRI taken 8 months after surgery showing complete tumour removal. The patient displayed only slight gait and balance disturbance, with no other deficits.
Gangliogliomas are mixed tumours (mostly WHO grade 2) containing elements of glial cells (forming the tissue “supporting” the brain) and neural cells. They grow rather slowly and can be easily separated from the healthy brain tissue. Surgery is the first-line treatment option. Only in the case of malignant tumours (grade 3 and 4) is radiotherapy and/or chemotherapy used.
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A: MRI of a 1.5-year-old boy with a monstrous ganglioglioma of the right hemisphere. The tumour causes visible skull asymmetry. First chemotherapy was introduced, with no satisfactory effect. The tumour kept growing. In spite of the very large size of the tumour and its rich blood supply surgery is the treatment of choice.
B: Intraoperative picture: Tumour disrupted the meninges.
C: Follow-up MRI after the first surgery showing partial removal of the tumour. Due to the rich blood supply of the tumour first only half of its mass was removed to avoid massive blood loss.
D: 3 months later the remaining part of the tumour was removed. Follow-up MRI after 4 months showing complete tumour removal.
E: The patient after the surgery.
Prof. Dr. med. Henry W. S. Schroeder, Tel.: 03834-86-6162,
Fax: 03834-86-6164, E-Mail: Henry.Schroeder@uni-greifswald.de