11. Majority are sporadic
Risk factors include;
Smoking
Diet
Occupation
Genetic abnormalities:
Neurofibromatosis type 1
This is caused by mutation on chromosome 17, which encodes the protein
neurofibromin and is associated with astrocytomas as well as neurofibromas.
12. Neurofibromatosis type 2:
This is caused by a mutation on chromosome 22, which encodes the
protein schwannomin , and is characterized by bilateral vestibular
Schwannomas (acoustic neuroma) as well as an increased incidence of
meningiomas.
14. Focal neurological deficits:
Frontal lobe lesions
Personality change
Gait ataxia
Urinary incontinence
Contralateral hemiparesis if posterior frontal lobe is involved
Dysphasia if left inferior frontal gyrus in dominant frontal lobe is
involved
15. Parietal lesions
Non-dominant side
Sensory inattention
Dressing apraxia
Astereognosis
Dominant side
Left-Right disorientation
Finger agnosia (Gerstmann’s syndrome)
Acalculia = unable to calculate
Agraphia = unable to wright
16. Occipital lobe lesion
Visual field deficits, most commonly on incomplete contralateral
homonymous hemianopia
Temporal lobe lesion
Non-dominant side
Disturbance of memory
Contralateral superior quadrantanopia.
Dominant side
Dysphasia
17. Other classical focal deficits associated with tumours include;
Bitemporal hemianopia with a pituitary macroadenoma compressing
optic chiasma
Anosmia
Ipsilateral optic atrophy and contralateral papilledema with an anterior
skull base meningioma (Foster-Kennedy syndrome)
Ipsilateral hearing loss
Tinnitus and disequilibrium with a vestibular Schwannoma
18. Hypersecretory pituitary tumours
Clinical syndromes
Prolactin hormone:
Primary or secondary amenorrhoea
Galactorrhea
Impotence
Growth hormone:
Gigantism if prepubetal
Acromegally in adults
Adrenocorticortropic hormone:
Cushing syndrome due to excessive cortisol production.
