Final Exam Study Guide (New Material) Flashcards
what is a neoplasm
abnormal mass tissue
around 45% of intracranial tumors arise from
neuroglia cells
what are neuroglial cells
non-excitable support cells of CNS & make up about ½ volume of CNS
what are the 4 types of neuroglia cells
astrocytes
oligodendrocytes
microglia
ependymal cells
what are astrocytes
star shaped cells & provide barrier at synapses that contain NT or hormones (dopamine)
what are oligodendrocytes
active in forming myelin sheath in central n fibers
what are migroglia
small glial cells that ingest & remove neural residue during inflammation & degeneration in CNS (phagocytic)
what are ependymal cells
epithelial cells lining CSF & are ciliated and facilitate CSF circulation & production
what are benign tumors
slow growing, well-defined borders for easy removal (surgery is good treatment), no metastasizing or life threatening, will kill if in crucial areas
what are malignant tumors
grow fast, invade & destruct structures, life threatening, can metastasize
explain how a benign and malignant tumors are intertwined
A large benign tumor, such as a CN VIII schwannoma, pressing against vital brainstem structures can lead to serious medical problems, even death
On the other hand, a small malignant tumor, such as an astrocytoma, although highly invasive, initially, may not interfere with neural function and may temporarily escape detection
what is an intra-axial tumor
originate in parenchyma of brain
ex: astrocytoma, glioblastoma
what is an extra-axial tumor
tumors that originate not from parenchyma of brain
ex: meningiomas, CN sheaths, pineal & pituitary glands
what are the 4 segments of the temporal bone
petrous (IE & hard segment)
Squamous
Mastoid
Tympanic (forms EAC, matures by 3 yrs old)
where do majority of vascular malformations in temporal bone present
in IAC or geniculate ganglion of VII N location in fallopian (facial) canal
preference in this region is though to be due to blood supply around ganglion
rarely in ME cavity or EAC
what are the two vascular tumors
hemangiomas & vascular malformations
What happens in hemangiomas
Extra blood vessels that group together into a dense clump
Most go through phases of growth & then go away on their own
what are findings in hemangiomas/vascular malformations/vascular tumors
Symptoms present ~3rd decade of life
-Geniculate Ganglion site→CHL (erodes ME cavity), facial weakness/twirch
-IAC site→ progressive SNHL, vertigo (CN VIII lesion)
-Tinnitus, hemifacial spasm
what are D/D for vascular tumors (H & VM)
-from other temporal bone tumors→ by radiographic appearance
-meningiomas→ irregular margins, may contain calcium flecks
-VII N schwannoma→less localized,
-cholesteatomas (also vascular lesion)→ seen in ME cavity
how are vascular tumors diagnosed
-Case hx & symptoms
-High res CT→intra tumor calcification shows here
-MRI w/ contrast→fluid is bright on T2 weighted more than acoustic schwannomas
why use an mri with contrast for vascular tumors
luid is bright on T2 weighted more than acoustic schwannomas
what is the management for vascular tumors
Surgery, thermal ablation, embolization
-Recurrence is low
more common vascular tumor that is present at birth
vascular malformation
rare and comprise 1% of temporal bone tumors
vascular malformation