Ch. 6 - Brain tumors Flashcards
Most common CNS tumor associated with NF-1
Optic nerve glioma
What is the hallmark tumor of NF-1?
Peripheral neurofibroma
What is the hallmark tumor of NF-2?
Bilateral acoustic schwannomas
What are the most common cerebral tumors?
Astrocytoma, including GBM (44%)
Metastases (15%)
Meningioma (15%)
Pituitary (8%)
Acoustic neuroma (8%)
What does ‘malignant’ refer to in brain tumors?
Aggressive biological characteristics, rather than tendency to metastasize
What is the most common astrocytoma in adults?
Glioblastoma multiforme
Describe the macroscopic appearance of GBM
Highly vascular margin with necrosis in center with microscopic nests of tumor cells extending outward into brain
Do high- or low-grade astrocytomas have a capsule?
Neither, and they have no distinct tumor margins
What is the most frequent initial symptom in patients with cerebral astrocytoma?
Seizures (occur in 50-75%); more common if tumor is adjacent to cortex
Where are astrocytomas typically found in adults compared to children?
Adults - cerebrum
Children - cerebellum
Imaging modality of choice for astrocytomas
MRI is more sensitive than CT (e.g. low-grade gliomas do not enhance with contrast); higher signal intensity on T2-weighted images
Identify the lesion
‘Butterfly’ lesion of GBM
What is the median survival for GBM after surgery? With adjuvant radiation?
Surgery - 17 weeks
Adjuvant radiation - 37 weeks
What is the role of adjuvant radiation following surgery for low-grade astrocytoma?
Not shown to improve survival
What is the most common location for oligodendrogliomas?
Nearly all are above the tentorium with most in the cerebral hemispheres (1/2 of these in the frontal lobes)
Describe the histologic appearance of oligodendrogliomas
Typically well-differentiated with calcium deposits in 90%
What is the most common symptom of oligodendrogliomas?
Epilepsy (in 80%), especially common because they are slow-growing
What is the major differential diagnosis for a recurrent cerebral glioma?
Postradiotherapy radiation necrosis (can develop as early as 4 months or as late as 9 years after therapy)
What is the most common location for ependymomas?
Infratentorial comparment (2/3 of cases)
What is the most common ependymoma location for children? Adults?
Children - infratentorial
Adults - supratentorial
What is the macroscopic appearance of ependymomas?
Well-demarcated, nodular, soft and pale; calcification is common
What histologic feature is diagnostic for ependymomas?
Perivascular pseudorosettes (eosinophilic halo composed of radiating tapering processes)
What is the origin of most tumors in the pineal gland region?
Germinomas
What is the classic presentation of a pineal gland tumor?
Endocrine disturbance (e.g. precocious puberty) in a male
Parinaud’s syndrome
Dorsal midbrain syndrome - limitation of upgaze, convergence paresis with impairment of reaction of pupils to light and accomodation
What is the preferred management of pineal gland tumors?
Radiotherapy (very sensitive)
What proportion of brain tumors are metastases? From where?
15% (though pathologists report up to 30%)
Lung > breast > melanoma > kidney > GI
Metastases occur most often in the distribution of what artery?
Middle cerebral artery
Which metastatic tumors are most likely to present with intracerebral hemorrhage?
Melanoma and choriocarcinoma
What are the indications for surgical removal of metastases?
Solitary metastasis in an accessible location AND no systemic spread
Meningeal carcinomatosis
Widespread, multifocal seeding of the leptomeninges by systemic cancer
What has the increase in cerebral lymphoma incidence over the past decade been attributed to?
AIDS and the use of immunosuppressive therapy
What is the most common site for primary cerebral lymphoma?
Frontal lobe >> temporal > parietal > deep nuclei
What therapy has the highest clinical response for cerebral lymphoma?
Radiotherapy with up to 80% response rate; however median survival is only improved by 15 months
From what sinuses do paranasal sinus tumors most commonly arise?
Ethmoid or maxillary
Paranasal sinus tumors are usually of what histologic type?
Squamous cell or adenoid cystic adenocarcinoma
What is the usual presentation of paranasal sinus tumors?
Blood-stained or purulent nasal discharge and pain
What are chordomas and where do they usually arise?
Rare tumors from notochord cell nests; most common at ends of axial skeleton (basioccipital or sacrococcygeal region)
What is the most common form of solid tumor in childhood?
Intracranial tumors
What proportion of pediatric brain tumors occur in the posterior fossa and what are the most common types?
60%; cerebellar astrocytoma > medulloblastoma > ependymoma
What is the usual location of medulloblastoma?
Cerebellar vermis; may be in the lateral cerebellum in older patients
What is the prognosis of cerebellar astrocytoma in children?
75% cure rate; most favorable of all intracranial pediatric neoplasms
Where do brainstem gliomas most commonly arise?
Pons > medulla
Presentation of brainstem glioma
Multiple bilateral CN palsies, internuclear ophthalmoplegia, apathetic personality changes
