Overview

Question 1

What is the estimated annual incidence of primary CNS tumors in the United States?

Answer 1

∼80,000 cases/yr of CNS tumors (∼1/3 of cases are malignant, 2/3 are nonmalignant tumors)

Question 2

What is the most common intracranial tumor?

Answer 2

Brain mets (20%–40% of all cancer pts develop brain mets)

Question 3

What are the most common primary histologies associated with brain mets?

Answer 3

Most common: lung, breast, melanoma

Question 4

Which primary histologies are associated with hemorrhagic mets?

Answer 4

RCC, melanoma, and choriocarcinoma are associated with hemorrhagic mets.

Question 5

Which primaries tend to metastasize to the PF?

Answer 5

GU/Pelvic primaries tend to go to the PF, where they are more likely to have a mass effect.

Question 6

What is the most common type of primary CNS tumor in adults?

Answer 6

Meningioma (36%) > Glioma (25% of all primary cases, 80% of all malignant tumors)

Question 7

What % of CNS tumors are mets vs. glioma vs. other?

Answer 7

Of all CNS tumors, roughly one-third are mets, one-third are gliomas, and one-third are other (meningioma, schwannoma, pituitary, lymphoma, etc.)

Question 8

What % of adult astrocytomas are low grade vs. high grade?

Answer 8

25% low grade vs. 75% high grade

Question 9

What is the most common histologic type of malignant CNS tumor in children? In adults?

Answer 9

Children: juvenile pilocytic astrocytoma (JPA) (20% <14 yo vs. 12% >14 yo)

Adults: GBM

Question 10

What is the most common benign intracranial tumor in adults?

Answer 10

Meningioma

Question 11

What is the strongest risk factor for developing CNS tumors?

Answer 11

Ionizing RT in children (no threshold—glioma, meningioma, nerve sheath)

Question 12

What CNS tumors are linked to NF-1?

Answer 12

Optic glioma, JPA

Question 13

What CNS tumors are linked to the NF-2?

Answer 13

Bilat acoustic neuroma, spinal ependymoma

Question 14

What CNS tumors are linked to the Tuberous sclerosis?

Answer 14

Subependymal giant cell astrocytoma, retinal hamartoma

Question 15

What CNS tumors are linked to Von Hippel–Lindau?

Answer 15

Hemangioblastoma

Question 16

What CNS tumors are linked to Li-Fraumeni?

Answer 16

Glioma

Question 17

What CNS tumors are linked to Cowden?

Answer 17

Meningioma

Question 18

What CNS tumors are linked to Gorlin?

Answer 18

MB

Question 19

What CNS tumors are linked to Turcot?

Answer 19

MB, GBM

Question 20

What CNS tumors are linked to RB?

Answer 20

Pineoblastoma

Question 21

What CNS tumors are linked to Ataxia telangiectasia?

Answer 21

CNS lymphoma

Question 22

What CNS tumors are linked to MEN-1?

Answer 22

Pituitary adenoma

Question 23

What are the 4 factors used for grading in the WHO brain tumor grading system?

Answer 23

Nuclear Atypia

Cellularity and Mitosis

Endothelial proliferation

Necrosis

(Mnemonic: AMEN)

WHO grade I = no factors present

WHO grade II = atypia

WHO grade III = atypia, mitoses

WHO grade IV = endothelial proliferation or necrosis

Question 24

Which CNS entities/pathologies are known to cross midline?

Answer 24

GBM, RT necrosis, meningioma (extra-axial can spread along meninges to contralat side), epidermoid cyst, multiple sclerosis

Question 25

What CNS tumors tend to have CSF spread?

Answer 25

MBs and other blastomas (except astroblastoma/GBM), CNS lymphoma, choroid plexus carcinomas, germ cell tumors, and mets

Question 26

What CNS tumors have Flexner–Wintersteiner rosettes?

Answer 26

Pineoblastoma and RB (any PNET)

Question 27

What CNS tumors have psammoma bodies?

Answer 27

Meningioma and pituitary tumors (uncommon)

Question 28

What CNS tumor type exhibits Verocay bodies? Schiller–Duval bodies?

Answer 28

Schwannomas exhibit Verocay bodies, and yolk sac tumors exhibit Schiller–Duval bodies.

Question 29

Which CNS tumors have Homer Wright rosettes?

Answer 29

NB, MB, pinealoblastoma, and PNET

Question 30

What CNS tumor has pseudorosettes?

Answer 30

Ependymoma

Question 31

What receptors are commonly overexpressed in gliomas?

Answer 31

EGFR (30%–50% in GBM tumors) and PDGFR (non-GBM tumors)

Question 32

Neural stem cells express which marker? Why are they important?

Answer 32

CD133. Neural stem cells are thought to be precursors for astrocytomas.

Question 33

What gene on chromosome 17 is frequently lost in both low- and high-grade gliomas?

Answer 33

The p53 gene is frequently lost in low- and high-grade gliomas.

Question 34

What is the genetic mutation in NF-1, and for which sites does it predispose to gliomas?

Answer 34

In NF-1, the genetic mutation is 17q11.2/neurofibromin. It predisposes to optic/intracranial gliomas.

Question 35

Name some acute RT complications in pts receiving RT for CNS tumors.

Answer 35

Alopecia, dermatitis, fatigue, transient worsening of neurologic Sx, n/v, otitis externa, seizures, and edema

Question 36

What is the timing and mechanism of somnolence syndrome?

Answer 36

6–12 wks post-RT, due to transient demyelination of axons

Question 37

What are some common late complications of RT to the CNS? What is the timing for these?

Answer 37

Radionecrosis, leukoencephalopathy, retinopathy, cataracts, endocrine deficits, memory loss, learning deficits, and hearing loss; 3 mos to 3 yrs