Intracranial tumors Flashcards
Primary Brain tumor classification by cell type, 3 major types
Neuroepithelial cell tumors - all of the glia and neuron type tumors, embryonic cell tumors.
Nerve sheath cell tumors - neurofibromas, neurosarcomas
Mesenchymal cell tumors - Meningiomas, Meningiosarcomas, Melanomas.
brain tumor metastases usually come from:
Breast, LUng, Melanoma, Colon, or renal cell.
Brain tumor classification by location
Intra-axial - within the parenchyma,
Extra-axial, outside of it,
in the meninges,
in the Sella Turcica, ie, pituitary tumors
Craniopharyngiomas
Ependymomas in the ventricle, choroid plexus.
Supratentorial, Infratentorial.
What is the main goal of imaging brain tumors
To determine if its intra or extra-axial,
affects treatment plan. extras can be operated more easily.
Common childhood brain tumors
Medulloblastoma, craniopharyngioma, ependymoma
CT and MRI characteristics of brain tumors
They are not confined to a vascular supply bed.
They have a perifocal hypodense/hypointense region or glove.
MRI T1 weighted they are hypointense
T2 they are hyperintense
Tumors can be contrast enhancing due to breakdown of the BBB allowing contrast uptake. Occurs in tumors, inflammation, demyelinating lesions, and ischemia.
Stronger enhancement indicates higher malignancy.
Mass effects of tumors
Midline dislocation
Compression of the ventricles
Hydrocephalus due to CSF flow obstruction
Herniation, tentorial, saggital, magnum
Astrocytomas
MRI is best
Contrast enhancement increases with malignancy
Perifocal edema, hypointense glove around the tumor
Oligodendroglioma
Have poor contrast enhancement.
Often have calcifications
hypointense on T1, hyper on T2.
Ependymoma
Mostly in children, growing near the ventricles.
Commonly causes obstructive hydrocephalus.
Medulloblastoma
the MOST COMMON malignant childhood CNS tumor.
Very commonly appear growing in the roof of the 4th ventricle.
Grow rapidly and cause obstructive hydrocephalus.
On T2 are hyperintense, but heterogenous mass due to areas of necrosis and calcficiation.
PNET tumor
primitive neuroectodermal tumor
Heterogenous rapidly growing tumor with cystic and necrotic regions.
Intense contrast enhancement.
Meningioma
The most common intracranial tumor, it is usually benign, and has minimal symptoms that don’t present until it is quite large.
Cause thickening of the nearby dura, creating a “dural tail sign” around the tumor.
Contrast enhance.
Extra-Axial.
Isodense on CT.
Can have sclerotic or calcified foci.
Vestibular schwannoma
Aka an Acoustic neuroma.
Most often around the sheath of CN 8 vetstibulocochlear nerve.
Substantial MR contrast enhancement.
Hemangioblastoma
Most often in the cerebellum
Strongly enhancing. Peripherally then retaining.
