1. Brain SOL 2

2. Meningiomas
Arise from the dura mater and are nearly always benign, well-demarcated lesions that displace rather than invade the adjacent neural tissue as they grow.
These mesodermal tumors most often become clinically evident between the ages of 40 and 50.
They are diagnosed by MRI or CT scanning which reveals marked, homogeneous contrast enhancement Meningiomas tend to appear in certain classic locations with corresponding typical neurological manifestations. They often grow very slowly and are not uncommonly discovered as an incidental radiological finding. The indications for treatment must then be carefully considered: resection may be desirable in younger patients, but unnecessary in older ones.

3. Common sites of meningiomas, and associated clinical features
Special features
course
Most common initial manifestations
Site
The frontal branch of the temporal artery may be enlarged
Epilepsy,personality changes,possible involvement of optic nerve
Anosmia
Olfactory groove
Hemiparesis
Epileptic seizures
Convexity
Rarely causes hemiparesis
Lower limb paresis;sometimes bilateral babinski sign
Parasagittal &falx
Lateral tumors may be evident as temporal hyperostosis
Exophthalmus,
hemiparesis
Visual disturbances(when medially located adjacent to optic nerve
Sphenoidal wing

4. Common sites of meningiomas, and associated clinical features
Special features
Course
Most common initial manifestation
Site
Progressive visual field defect
Visual disturbances,pale optic disc
Tuberculum sellae
Diff.diagnosis
Acoustic neuroma
facial&5th nerve deficit
Brainstem compression
Deafness,vertigo
Cerebellopontine angle
Lower cranial n.palsy
Spastic quadriparesis,dys-
phasia,dysarthria
Foramen magnum
Often found in trigone
Progressive hydrocephalus
Intermittent headaches,vomiting
Intraventricular

5. Meningioma of the left cerebral convexity

6. Falx meningioma

7. Sphenoid wing meningioma

8. Pituitary tumors
Usually arise from the cells of the anterior pituitary lobe.
Depending on their cells origin, they can produce hormones in excess or cause hormone deficiency.
Thus, they present clinically with endocrine disturbances and/or compressive effects on the adjacent neural tissue .
They most commonly present between the ages of 30 and 50.
The rare eosinophil adenomas produce excessive growth hormone, causing acromegaly,while basophil adenomas produce excessive ACTH, causing Cushing syndrome (which,when caused by a pituitary tumor, constitutes Cushing disease).
Prolactinomas produce galactorrhea and secondary amenorrhea in women and impotence in men.
Although basophil adenomas and prolactinomas rarely cause mass effect, eosinophil adenomas and, above all, the hormonally inactive chromophobe adenomas tend to grow quite large, causing compression and dysfunction of the normal pituitary tissue, clinically evident as hypopituitarism (multiple pituitary hormone deficiencies, including hypothyroidism and secondary hypogonadism). Chromophobe adenomas can also compress the optic chiasm, causing a visual field defect, usually bitemporal upper quadrantanopsia or bitemporal hemianopsia. Compression of the optic nerves themselves may impair visual acuity.

9. Prompt neurosurgical removal of the tumor can often reverse these visual difficulties if they are still incomplete at the time of surgery.Most pituitary tumors do not present with signs of mass effect (only one in 10 enlarges the sella turcica visibly on plain films of the skull).
Tumors that do cause mass effect should be neurosurgically removed, preferably by the transsphenoidal route.
Hormonally active microadenomas can sometimes be
treated with medication alone (e. g., prolactinoma can be
treated with inhibitors of prolactin secretion, such as
(bromocriptine and lisuride).

11. Craniopharyngioma
Arises in or above the pituitary fossa, often growing upward toward the diencephalon and third ventricle.
This is a cystic tumor derived from epithelial remnants in Rathke’s pouch,
Generally containing calcifications as well as cholesterol
crystals. It presents with hypopituitarism , diencephalic manifestations (diabetes insipidus), and visual disturbances.
Like a pituitary tumor, it can cause hemi- or quadrantanopsia and impair visual acuity; it can also cause occlusive hydrocephalus.
Craniopharyngioma is the most common suprasellar tumor in children and adolescents. It is best treated by complete resection

12. ACOUSTIC NEUROMA
This is a benign tumour of Schwann cells of the 8th cranial nerve, which may arise in isolation or as part of NF2 .
As an isolated finding, an acoustic neuroma occurs after the third decade and is more frequent in females. The tumour commonly arises near the nerve's entry point into the medulla or in the internal auditory meatus, usually on the vestibular division. Such lesions make up 80-90% of tumours at the cerebello-pontine angle.

13. Clinical features
These depend on the site of the tumour along the acoustic or vestibular nerve. Similar tumours arise rarely from the trigeminal nerve.
Hearing loss is almost invariable, although it may not be the presenting feature. Sensory symptoms in the face and vertigo are also common at presentation. Distortion of the brain stem and/or cerebellar peduncle may cause ataxia and/or cerebellar signs in the limbs.
Distortion of the fourth ventricle and cerebral aqueduct may cause hydrocephalus, which may be the presenting feature .
Facial weakness is unusual at presentation, but facial palsy may follow surgical removal of the tumour.

14. Investigation Management
MRI is the investigation of choice , CT being less useful in this region of the posterior fossa.
Management
This involves surgical removal. If this is complete, the prognosis is excellent. Deafness and facial weakness, if not present before surgery, usually result from the operation.

16. Ependymoma Is a benign tumor usually seen in children and adolescents.
On pathological examination, these tumors are often cystic and partly calcified. They develop from the neuroepithelium of the walls of the cerebral ventricles and the central canal of the spinal cord; as they grow, they displace, but do not invade, the adjacent neural tissue Ependymomas usually arise in the posterior fossa,most commonly near the fourth ventricle, and in the conusmedullaris of the spinal cord.Their main clinical manifestations are focal (often cerebellar) neurological deficits and signs of intracranial hypertension secondary to compression of the CSF pathways and occlusive hydrocephalus. An unusually persistent, continuous headache in children should arouse suspicion of an ependymoma or other mass in the posterior fossa.
The treatment is by resection, followed by radiotherapy of the entire neuraxis. Seventy percent of treated patients survive for 10 years or longer.

17. Ependymoma growing out of the fourth ventricle

18. Astrocytoma
the most common category of neuroepithelial tumor, has the following histological subtypes

19. Glioblastoma multiforme
Is the most malignant grade of astrocytoma (grade IV astrocytoma). This most common and most malignant tumor of the cerebral hemispheres usually arises between the ages of 40 and 60. It grows by infiltration into brain tissue and is thus nearly impossible to resect totally, as nests of tumor cells nearly always remain beyond the margins of resection even if all macroscopically evident tumor tissue is removed Though it generally arises in a single hemisphere, it can infiltrate across the corpus callosum into the opposite hemisphere, creating a so-called butterfly tumor.

20. Glioblastomas grow rapidly, causing rapidly progressive clinical manifestations; they are, therefore, usually diagnosed within a few weeks or (at most) months of the onset of symptoms.
Focal neurological and/or neuropsychological deficits arise first, sometimes accompanied by epileptic seizures, soon followed by general manifestations of intracranial hypertension .
The diagnosis can be made with a fair degree of confidence from the typical appearance in neuroimaging studies , though this does not obviate the need for histological examination of tumor tissue. CT characteristically reveals a central hypodense area, corresponding to necrosis in the interior of the tumor. There may be hyperdense areas indicating intratumoral hemorrhage. Peritumoral brain edema is often extensive, causing mass effect and midline shift. Ringlike enhancement is seen after the administration of contrast medium.
Even with the best currently available treatment, i. e., gross total resection of the tumor with or without adjuvant radio- or chemotherapy, patients with glioblastoma survive only a few months, or a few years at most, because of the nearly inevitable recurrences.
Grade III astrocytoma , is another type of histologically malignant astrocytoma. The prognosis of patients with this type of tumor, though marginally better than that of glioblastoma patients,is still poor.

21. Glioblastoma multiforme in the right frontal lobe
Glioblastoma multiforme in the right frontal lobe. The T1- and T2- weighted spin-echo images (a and b,respectively) reveal a polycystic tumor surrounded by marked edema.

22. MRI illustrate a large tumor deep within the left cerebral hemisphere and extending through the corpus callosum to the right hemisphere. The black rim around a portion of the tumor (left) represents hemorrhage.

23. Grade III astrocytoma (partly cystic) in the right parieto- temporal region, as revealed by MRI.

24. Grade I and II astrocytomas
Generally affect adults aged 30 to 40. Though these tumors displace & infiltrate the surrounding brain tissue, they are better demarcated from it than glioblastoma; they often grow quite slowly, sometimes over many years. Their clinical manifestations include behavioral and neuropsychological changes, increasingly severe focal neurological deficits (e. g., hemiparesis), focal or secondarily generalized epileptic seizures, and signs of intracranial hypertension.
If epileptic seizures are the only manifestation, tumor resection may be useful for seizure control, if the location of the tumor permits. After a tumor is totally resected, it may not recur until years later.

25. Astrocytoma of the left frontal lobe; the T2-weighted MRI shows an infiltrating tumor with minimal mass effect and slight edema.

26. Cerebellar astrocytoma
Is considerably more benign than the other varieties, usually affects children aged 5 to 15 ,and is well demarcated from the surrounding brain tissue. It is usually found in the cerebellar hemispheres or vermis and may extend into the pons.
Its main clinical manifestations are thus ataxia, disequilibrium, nystagmus, and, often, signs of intracranial hypertension (esp. papilledema) secondary to occlusive hydrocephalus.
Total resection often results in permanent cure.
Brainstem astrocytoma is usually inoperable, though
tumors of this type are sometimes at least partly re-
sectable in special cases.

27. Cystic astrocytoma of the cerebellum
Cystic astrocytoma of the cerebellum. MRI demonstrates the large cystic component of the tumor (smaller arrow) and the solid tissue component (larger arrow)

28. Brain metastases
Account for about 15% of malignant brain tumors. The most common source of a brain metastasis is bronchial carcinoma in men and carcinoma of breast in women.
Brain metastases sometimes produce symptoms before the primary tumor does; in such cases,multiple brain metastases are usually
already present, even if only a single one is apparent on the neuroimaging study.
Generally speaking, surgical resection makes sense only for solitary metastases and the surgical indication should always be carefully considered in the light of the extent of disease.Only about 20% of patients so treated live more than five years after the operation and postoperative radiotherapy, if they have not already died of the effects of their primary tumor.
Brain metastases usually produce extensive peritumoral edema and often cause epileptic seizures; thus, corticosteroids and antiepileptic drugs can be given for palliation. This usually brings a substantial, if only temporary, clinical improvement.

30. Multiple metastases from bronchogenic carcinoma
Multiple metastases from bronchogenic carcinoma. Each lesion is surrounded by edema

31. Hydrocephalus
Obstruction to the CSF circulation leading to dilatation of the ventricular system.
Communicating H. :the obstruction lies outside the ventricular system.
Non-communicatin H. : the obstruction is within the ventricular system .

32. Causes of hydrocephalus
Communicating (obstruction outside ventricular system)
Bacterial meningitis (especially tuberculous)
Sarcoidosis
Subarachnoid haemorrhage
Head injury
Idiopathic ('normal pressure)
Non-communicating (obstruction within ventricular system)
Tumours
Colloid cyst
Arnold-Chiari malformation
Aqueduct stenosis
Cerebellar abscess
Cerebellar or brain-stem haematoma

33. Diversion of the CSF by means of a shunt procedure between the ventricular system and the peritoneal cavity or right atrium may result in prompt relief of symptoms in obstructive or communicating hydrocephalus.

34. NORMAL PRESSURE HYDROCEPHALUS
In this condition the dilatation of the ventricular system is caused by intermittent rises in CSF pressure, which occur particularly at night.
It occurs predominantly in old age and is suggested by the combination of gait apraxia and dementia, often with urinary incontinence as an early feature. This cause of dilatation of the ventricles can be very difficult to distinguish from that occurring due to cerebral atrophy, where the cortical sulci are also dilated.
The result of shunting procedures for normal pressure. hydrocephalus is unpredictable

35. IDIOPATHIC INTRACRANIAL HYPERTENSION
This condition, previously known as 'benign intracranial hypertension' and 'pseudotumour cerebri', usually occurs in obese young women. Raised intracranial pressure develops without a space-occupying lesion, ventricular dilatation or impairment of consciousness.
The aetiology is uncertain but there may be a diffuse defect of CSF reabsorption by the arachnoid villi.
The condition can be precipitated by drugs, including tetracycline, and rarely vitamin A, retinoids.

36. Clinical features
The usual presentation is with headache, sometimes with transient diplopia and visual obscurations. There are usually no signs other than papilloedema, which may be discovered incidentally, but a 6th nerve palsy may be present.

37. Investigations
The CT is normal, with normal-sized or small ventricles. Once this has been demonstrated, a lumbar puncture is safe and will allow confirmation of the raised CSF pressure and form part of treatment.
MR angiography or cerebral venography will exclude cerebral venous sinus thrombosis or stenosis of other cause. True papilloedema may need to be distinguished from other causes of disc swelling by fluorescein angiography.

38. Management
Any precipitating condition should be sought, relevant medication should be withdrawn and a weight-reducing diet started, if indicated.
The carbonic anhydrase inhibitor, acetazolamide, may help to lower intracranial pressure. Repeated lumbar puncture can be considered, but is often unacceptable to the patient.
Patients failing to respond, in whom chronic papilloedema threatens vision, may require optic nerve sheath fenestration or a lumbo-peritoneal shunt.
In patients with fixed stenosis of the transverse sinus , stenting may be helpful .

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