Page 355 - Medicine and Surgery

P1: FAW
BLUK007-07 BLUK007-Kendall May 25, 2005 18:18 Char Count= 0

Chapter 7: Tumours of the nervous system 351

Investigations tissue. The cells have round nuclei and pale vacuo-
Neuroimaging with CT or MRI – the latter is more lated cytoplasm (fried egg appearance).

sensitive and provides greater anatomical detail. As- Glioblastoma muliforme tumours may be necrotic,
trocytomas are usually highly vascular and enhance haemorrhagic masses due to rapid growth. They are
with contrast in over two-thirds of cases (less often composed of pleomorphic cells.
in low-grade astrocytoma). Surrounding oedema is
commonly seen, but due to the diffuse infiltration, Management
It is still unclear whether early complete surgical re-
the limits of oedema often demarcate the limits of
moval of low-grade tumours that cause little or tran-
the tumour spread. For this reason, prior use of cor-
sient neurology improves the prognosis; although
ticosteroids can reduce the appearance of the size of
surgery is helpful for reducing the need for treatment
the tumour. Oligodendromas commonly calcify. CT
of seizures, it has the disadvantage of often causing
is less useful then MRI.
major neurological deficit.
Biopsy – stereotactic biopsy (linking information for

For astrocytomas, complete surgical removal is diffi-
CT and MRI to guide surgery via surface landmarks
cult due to the diffuse nature and difficulty in deter-
or a frame to achieve accuracy to within 1 mm) is used
mining the limits of the tumour. For high-grade as-
whichincreasessensitivity,andreducesmorbidityand
trocytomas, in many cases the tumour is unresectable.
mortality.
Even if the tumour is resectable, the high risk of recur-
rence, together with the major morbidity of surgery
Macroscopy/microscopy
may mean debulking surgery only and treatment with
Astrocytomas are ill-defined pale areas which are not

radiotherapy and/or chemotherapy.
clearly demarcated from the adjacent brain. The cells
Hydrocephalus can be treated with a shunt. Seizures
look like astrocytes and there are different histological are treated with anti-epileptic drugs.
patterns.
Oligodendrogliomas are macroscopically similar to Prognosis

astrocytomas, arising as greyish white lesions that Low-grade tumours grow slowly over many years while
are not clearly differentiated from the surrounding glioblastoma multiforme causes death within months.