Adult Primary Brain Tumors

Question 1

Glioblastoma multiforme (grade IV astrocytoma)

Answer 1

Most common 1 degree brain tumor. Malignant with < 1-year life expectancy. Found in cerebral hemispheres. Can cross corpus callosum (“butterfly glioma”). Stain astrocytes for GFAP.
“Pseudopalisading” pleomorphic tumor cells - border central areas of necrosis and hemorrhage.

Question 2

Meningioma

Answer 2

2nd most common 1 degree brain tumor. Most often occurs in convexities of hemispheres (near surfaces of brain) and parasagittal region. Arise from arachnoid cells, are extra-axial (external to brain parenchyma), and may have a dural attachment (“tail”). Typically benign and resectable. Often asymptomatic; may present with seizures or focal signs.

Notes:
Spindle cells concentrically arranged in a whorled pattern; psammoma bodies (laminated calcifications).

Question 3

Schwannoma

Answer 3

3rd most common 1 degree brain tumor. Schwann cell origin; often localized to CN VIII -> acoustic schwannoma (aka acoustic neuroma). Resectable or treated with stereotactic radio surgery. Usually found at cerebellopontine angle; S-100 positive.

Notes:
Bilateral acoustic schwannoma found in neurofibromatosis type 2.

Question 4

Oligodendroglioma

Answer 4

Relatively rare, slow growing. Most often in frontal lobes. Chicken-wire capillary pattern. Oligodendrocytes = “fried egg” cells - round nuclei with clear cytoplasm. Often calcified in oligodendroglioma.

Question 5

Pituitary adenoma

Answer 5

Most commonly prolactinoma. Bitemporal hemianopia (due to pressure on optic chiasm) and hyper- or hypopituitarism are sequelae.