Download Extra-axial Syndromes

#3. Recognize specific syndromes; extra-axial
(cerebellopontine, pituitary, frontal) and intraaxial in brain tumor presentation
Extra-axial Tumors
• Extrinsic to the brain
• include meningiomas, schwannomas,
neurofibromas, and pituitary tumors,
craniopharyngiomas as well as mesenchymal
tumors of the skull, spine, and dura mater
Meningioma
• Derived from arachnoid cap cells of the arachnoid
mater
• Appear to arise from the dura mater grossly and
on MRI: “dural based tumors”
• Most common intracranial locations: along the
falx cerebri , the convexities and the sphenoid
wing.
• Less common locations: foramen magnum,
olfactory groove, and inside the lateral ventricle
Meningioma
• Mostly slow growing, encapsulated, and
benign
• Malignant  may invade adjacent bone or
into the cortex
• Previous cranial irradiation:
risk
• Tx: Total resection, post op radiation (atypical
and malignant melanoma)
Postcontrast T1-weighted coronal MRI
demonstrating a brightly enhancing
lesion arising from the falx cerebri with
moderate edema and mass effect on the
right lateral ventricle. This is a falcine
meningioma. Note also the small
separate meningioma arising from the
dura over the cerebral convexity.
Vestibular Schwannoma (Acoustic
Neuroma)
• Arise from the superior half of the vestibular
portion of the vestibulocochlear nerve (CN VIII)
• commonly present with progressive hearing loss,
tinnitus, or balance difficulty
• Large tumors may cause brain stem compression
and obstructive hydrocephalus
• Bilateral acoustic neuromas are pathognomonic
for neurofibromatosis type 2, a syndrome
resulting from chromosome 22 mutation.
Vestibular Schwannoma (Acoustic
Neuroma)
• Tx: microsurgical resection or with conformal
stereotactic radiosurgery (gamma knife or
linear accelerator technology)
• Complication: damage to the facial nerve
(cranial nerve VII)
A. Postcontrast T1-weighted axial
MRI demonstrating a brightly
enhancing mass on the right
vestibular nerve with an
enhancing tail going into the
internal auditory canal
(arrowhead). Pathology
demonstrated vestibular
schwannoma
Pituitary Adenoma
• arise from the anterior pituitary gland (the
adenohypophysis).
• Microadenoma: <1cm; Macroadenoma >1 cm
• Functional (i.e., secrete endocrinologically active
compounds at pathologic levels) or nonfunctional
(i.e., secrete nothing or inactive compounds).
• The most common endocrine syndromes are
Cushing's disease due to adrenocorticotropic
hormone (ACTH) secretion, Forbes-Albright
syndrome due to prolactin secretion, and
acromegaly due to growth hormone secretion.
Pituitary Adenoma
• Nonfunctional tumors commonly present
when larger due to mass effect.
• Common symptoms : visual field deficits due
to compression of the optic chiasm, or
panhypopituitarism due to compression of the
gland.
• Tx: Surgery (Transphenoidal), medical
(Prolactinomas)
Postcontrast T1-weighted sagittal
MRI demonstrating a large
sellar/suprasellar lesion involving
the third ventricle superiorly, and
abutting the midbrain and pons
posteriorly. The patient presented
with progressive visual field and
acuity loss. Pathology and lab
work revealed a nonfunctioning
pituitary adenoma.
Hemangioblastoma
• occur almost exclusively in the posterior fossa.
• Twenty percent occur in patients with von
Hippel-Lindau (VHL) disease, a multisystem
neoplastic disorder
• Appears as cystic tumors with an enhancing
tumor on the cyst wall known as the mural
nodule.
• Surgical resection is curative for sporadic (nonVHL associated) tumors.
Craniopharyngioma
• Benign cystic lesions that occur most frequently in
children.
• Second peak of occurrence around 50 years of age.
• Symptoms result from compression of adjacent
structures, especially the optic chiasm, pituitary or
hypothalamic dysfunction or hydrocephalus may
develop.
• Treatment is primarily surgical
• Complications: Visual loss, pituitary endocrine
hypofunction, diabetes insipidus, and cognitive
impairment from basal frontal injury
Neurofibroma
• more fusiform and grow within the parent nerve,
rather than forming an encapsulated mass off the
nerve, as with schwannomas.
• They are benign but not encapsulated.
• They present similarly to schwannomas and the
two may be difficult to differentiate on imaging.
• Patients with multiple neurofibromas likely have
neurofibromatosis type 1, also known as von
Recklinghausen's neurofibromatosis.
• Resection for symptomatic lesions should be
offered.
Intra-axial Tumors
• Intrinsic to the brain
GLIOMA
• ASTROCYTOMA:
- MOST COMMON PRIMARY INTRA-AXIAL
BRAIN TUMOR (low & high grade)
- INVOLVE ALL LOBES WITH
PREFERENTIAL TO FRONTAL &
TEMPORAL LOBES
- GRADING BASED ON HISTOLOGY:
hypercellularity
pleomorphism
vascular proliferation necrosis
- DIAGNOSIS: CT, MRI, Angiography
- TREATMENT: Surgery, Radiation,
Chemotheraphy or Combination
ASTROCYTOMA
Pilocytic
Astrocytoma
Grade I
Low Grade
Astrocytoma
Grade II
Anaplastic
Astrocytoma
Grade III
Glioblastoma
Multiforme
Grade IV
Median Age
13 years
35-45 years
46 years
50-60 years
Incidence
2% of gliomas
5%-25% of
gliomas
10%-30% of
gliomas
45%-50% of
gliomas
Location
Cerebellum, Brain stem,
Optic nerve, Cerebral
hemisphere
Cerebral hemispheres
(frontal 40%), pons
thalamus, midbrain
Cerebral hemispheres,
thalamus, midbrain,
pons
Any region particularly
cerebral hemispheres
(frontal 40%)
Presentation
Depending on site, inc.
ICP, seizures, motor
deficit
Seizures(65%), Incr.ICP,
Mental status change,
motor deficit
Seizures(50%), Incr.ICP,
Mental status change,
motor deficit
Increased ICP, mental
changes, motor deficit,
seizures
Treatment
Surgical
resection
Surgical
resection
Sx resection,
radiaion,
chemoRx
Sx resection,
radiaion,
chemoRx
Outcome
5 year survival
100%
26%-33%
18%
5.5%
OLIGODENDROGLIOMA
Incidence
2-10%
Age of predilection
30-55 yrs
Gender distribution
Slightly more men (3:2)
Location
Frontal, temporal, parietal
often towards the midline
Cardinal clinical symptoms
Seizures (50%-80%)
CT native
Image as for astrocytma II or
III, calcifications in about 50%
of the cases, occasionally
cysts, “fried egg” cytoplasm
CT after contrast medium
Enhancement of Grade III
tumors only; variegated
picture, slight edema
Treatment: vary from conservative treatment of some
patients with serial imaging studies and no intervention to
aggressive multimodal treatment including surgical
resection, radiotherapy, and chemotherapy
EPENDYMOMA
• glial tumors that arise from ependymal cells
within the central nervous system
Incidence
1-4%
Age of predilection
0-20 yrs
Gender distribution
Predominantly men
Location
Fourth and third ventricles,
lateral ventricles, in childhood
frontal, superficial frontier
Cardinal clinical symptoms
Signs of intracranial pressure
increase
CT native
(10%)
Slightly increased
density;
calcification possible
CT after contrast medium
Slightly enhancement in solid
tumor parts; grades III and IV
similar to glioblastoma image
KEY FEATURES:
-USUALLY OCCUR IN THE
FLOOR OF THE 4TH VENTRICLE
-POTENTIAL FOR SEEDING THRU
THE NEURAXIS
-WORSE PROGNOSIS THE
YOUNGER THE PATIENT; 5 YRS
SURVIVAL AT 80% FOR ADULTS
& 20%-30% IN PEDIATRIC GROUP
-MAXIMAL RESECTION FOLLOWED BY
XRT
EPENDYMOMA