Brain Tumors
Brain Tumors
Differential diagnosis
• Low grade astrocytoma• High grade astrocytoma (Glioblastoma)• Meningioma• Oligodendroma• Brain abscess• Lymphoma• Schwannomas
High grade astrocytoma (Glioblastoma)
Clues to diagnosis: Astrocytoma
• Heterogenous mass• often infiltrate into adjacent brain• rarely have the clear margins
Oligodenroglioma
Clues to diagnosis: Oligodendroglioma
• Evidence of calcification in 30% of cases.
CNS lymphoma
Proton density–weighted MR image through the temporal lobe demonstrates a low signal intensity nodule (small arrows) surrounded by a ring of high signal intensity edema (larger arrows).
T1-weighted contrast-enhanced axial MRI demonstrates ring enhancement surrounded by a nonenhanced rim of edema. In this patient with AIDS, a solitary lesion of this type is consistent with either lymphoma or toxoplasmosis; the presence of multiple lesions favors toxoplasmosis
Meningioma
Clues to diagnosis: Meningioma
• Does not usually invade the brain• uniform contrast enhancement is essentially
diagnostic.• May have a dural tail.
Schwannomas
Axial noncontrast MR scan through the cerebellopontine angle demonstrates an extraaxial mass that extends into a widened internal auditory canal, displacing the pons (arrows)
Schwannoma
Postcontrast T1-weighted image demonstrates intense enhancement of the vestibular schwannoma (white arrow). Abnormal enhancement of the left fifth nerve (black arrow) most likely represents another schwannoma in this patient with neurofibromatosis type 2.