Brain Tumors Flashcards
Brain tumors
1/2 to 3/4 of tumors: primary, rest metastatic
20% of all cancers of childhood
70% of primary tumors arise in posterior fossa in childhood
adults: tentorium (separates cerebellum from occipital lobes)
What are the four unique characteristics of brain tumors?
– Distinction between benign and malignant lesss evident in CNS than other organs
– Ability to surgically resect infiltrating glial neoplasms without compromising neurologic function is limited
– Anatomic site of neoplasm can have lethal consequences even if benign tumor
– Primary CNS neoplasms rarely spread outside of CNS
What are the four major classes of brain tumors?
Gliomas
Neuronal tumors
Poorly differentiated neoplams
Meningiomas
What are the three types of gliomas?
– astrocytomas
– oligodendrogliomas
– ependymomas
Where in the brain are most astrocytomas found?
Cerebral hemispheres
What two morphologic features distinguish a glioblastoma ?
Tufts of proliferated endothelial cells bulge into vascular lumen = glomeruloid structures
Necrosis - pseudopalisaing tumor cells at edge of necrotic areas
What is the usual clinical scenario for a well differentiated astrocytoma?
Low grade - symptoms static or progress slowly for years then enter rapid decline, anaplastic and rapid growth
What is the usual clinical scenario for a well differentiated glioblastoma?
Prognosis very poor
What age group do oligodendrogliomas occur in?
Most common in middle life
Where are oligodendrogliomas located?
Located in cerebral hemisphere, white matter
How do oligodendroglioma patients present?
May complain of neurologic issues, including seizures
What are the two microscopic features? Oligodendrogliomas
Sheets of regular cells w/round nuclei surrounded by clear halo of cytoplasm (fried eggs)
Anastamosing network of capillaries: ‘chicken feet’
What are the two types of poorly differentiated neoplasms?
Medulloblastoma - 20% of childhood tumors, cerebellum
In what age group and where do medulloblastomas occur?
Children
Occlusion of the flow of CSF leads to what?
Hydrocephalus
What do the tumor cells look like? (Medulloblastoma)
Bland, small dark cells
What is the tumor sensitive to?
Radiation
Primary CNS lymphoma is the most common CNS neoplasm in what group of patients?
HIV/AIDS
What does the term primary emphasize?
Lymphoma is not a non-hodgkin lymphoma that spread to brain
Do brain lymphomas metastasize outside of the CNS and conversely do NHL’s outside of the CNS metastasize to the CNS?
No, not to brain parenchyma
Are meningiomas usually benign or malignant?
Benign
What age group do they occur in?
Adults
Meningiomas: location
Found along any external surface of brain as well as within ventricle system
Meningiomas: what cell do they arise from
Arise form meningothelial cell of arachnid, usually attached to dura
Meningiomas: clinical course?
Slow growing, may eventually have neuro manifestations
What cell do Schwannoma’s arise from?
Neural crest-derived Schwann cell
What familial syndrome are they associated with (Schwannoma’s)?
Inherited disorders characterized by harmatomas & neoplams located throughout the body mostly prominently involve nervous system
Many inherited autosomal dominant
Where are they most commonly located within the cranial vault? (Schwannoma’s)
Cerebellopontine angle (CPA), attached to vestibular branch of 8th nerve
How do patients present? (Schwannoma’s)
Tinnitus & hearing loss
What is the other name for the tumor? (Schwannoma’s)
“acoustic neuroma”
NF Type I
Neurofibromas (plexiform, solitary)
Acoustic nerve schwannomas
Gliomas of optic nerve
Lisch, cafe au lait
Gene of neurofibromin: 17
NF Type II
Autosomal disorder w/gene on chromosome 22
Propensity to develop tumors - bilateral Schwannomas of 8th nerve; multiple menengiomas
