Brain Neoplasms II Flashcards
What are the most common embryologic origins/sources and general location of adult brain tumors?
generally adult tumors are supratentorial
most primary tumors arise from neuroectoderm- most common of neuroectodermal orgin are astrocytomas
Meningiomas are 2nd most common tumor- mesodermal origin
15-25% are metastases (esp. of lung and breast tumors)
What are the astrocytomas in adults? genetics?
diffuse/fibrillary astrocytoma (general group):
astrocytomas, anaplastic astrocytomas, and gliobastoma multiforme (very bad prognosis)
often have p53 mutations/EGFR mutations
When are fibrillary astrocytomas most common and where do you see them?
3rd and 4th decade of life in the cerebral hemispheres by far most common.
What is gliomatosis cerebri? sites, age, prognosis
diffuse neoplastic transformation of poorly differentiated astrocytes. usually seen in at least 2 lobes. occurs at any age. fatal.
Age, sites, prognosis, detection of anaplastic astrocytoma
age: 4th-5th decade
cerebral hemisphers
prognosis: 50% 2-5 yr survival
detect when formerly non-anaplastic astrocytomas begin to show contrast enhancement
Glioblastoma multiforme: age, site, prognosis, genetics
age: 45-55 (or 5th and 6th decades, according to another part of the notes)
site: front lobe white matter, though anywhere possible
prognosis: about 15 mo. with aggressive surgery, radiation, and chemo :-(
EGFR mutation
Classic features of glioblastoma multiforme.
extend across the corpus callosum to give a BUTTERFLY distribution. often heterogenous and with hemorrhage, NECROSIS, and VASCULAR PROLIFERATION. Histologically, you see PSEUDOPALISADING or PALISADING around the necrotic areas. very hypercellular (duh, it’s cancer…)
What tumors give butterfly lesions?
Glioblastoma multiforme, lymphoma, and metastatic tumors
Oligodendrogliomas: site
frontal lobes/ frontotemporal white matter. Infiltrate the cortex. Cacifcations of blood common
What are the histologic featuures of oligodendrogliomas?
FRIED EGG appearance. Not very fibrillary. nuclei quite round.
calcification of blood
What should I know about pontine gliomas?
usually an infilltrating astrocytoma (not a pilocytic structure, which usually occur in the medulla or midbrain if seen in the brainstem). usually proceed without biopsy confirmation because imaging and clinical features so specifc
What should I know about adult ependymomas?
often seen in spinal cord and filum terminale. can be seen in the floor of the 4th ventricle.
better demarcated than astrocytomas
Perivascular pseudorosettes seen. anaplastic ependymomas also show incr. cell densitym pleomorphis, and mitotic activity
What should I know about meningiomas?
2:1 F:M in brain; 10:1 F:M in spinal cord. My be because progesteone is a growth factor.
Half show monosomy at 22q12, like acoustic shwannomas. Associated with neurofibromatosis type II. Arise form arachnoid cells, esp. parasagittal arachnoid, or in the thoracic region.
if malignant, occasionally seed CSF/distant metastasis
Histologic and gross features of meningiomas
very diverse, but classically a WHORL with INTRANUCLEAR OCCLUSIONS. Often have meningial TAIL. Occasionally invades the bone or dural sinuses.
What should I know about schwannomas?
benign. May also be an intraspinal tumor. often associated with the vestibular branch of the acoustic nerve (or the trigeminal nerve, slightly less commonly). Multiple central schwannomas, esp. bilateral acoustic schwannomas, are diagnostic of neurofibromatosis type II.
