Clinical features

Features tend to evolve over weeks or months, and may show sudden deterioration, probably associated with the accumulation of significant cerebral oedema.

Characteristically there may be:

• seizures
• raised intracranial pressure - headache, vomiting, altered level of conscious
• focal neurological signs - depend where the tumour is located - may include dysphasia, hemiparesis, altered personality

In children, juvenile astrocytomas may arise in the hypothalamus and present with failure to thrive, emaciation, and features of panhypopituitarism.

Alternatively, the pilocytic tumour may develop around the optic nerve and grow slowly anteriorly into the orbit or posteriorly into the optic chiasma. Visual field scotomas progress to complete field loss. Orbital extension produces proptosis. Posterior expansion beyond the chiasma may affect the hypothalamus. Optic nerve astrocytomas are rare after the first decade.

Assess carefully the patient who presents with difficult to control seizures who may harbour an astrocytoma.