CNS Tumors

Question 1

How does the location of brain tumors differ between adults and children?

Answer 1

Adults are usually supratentorial

Children are usually infratentorial (in the cerebellum)

Question 2

What is the difference between expansile and infiltrative tumor growth?

Answer 2

Expansile: sharp border
Infiltrative: single neoplastic cells spread throughout the parenchyma

Question 3

What are the major signs/symptoms of a CNS tumor?

Answer 3

Headache/nausea/vomiting from increased ICP
Syncope
Cranial nerve palsies
Focal neurologic deficits
Cognitive dysfunction

Question 4

What are the most common CNS tumors in adults?

Answer 4

Meningioma, schwannoma, glioma

Question 5

What are the most common CNS tumors in children?

Answer 5

Pilocytic astrocytoma, ependymoma, medulloblastoma

Question 6

List the types of gliomas

Answer 6

Astrocytoma (most common):
Oligodendroglioma
Ependymoma

Question 7

List the neuronal and mixed neuronal-glial tumors

Answer 7

Central neurocytoma
Gangliglioma
Dysembryoplastic neuroepithelial tumor (DNET)

Question 8

List the embryonal tumors

Answer 8

Medulloblastoma
Primitive neuroectodermal tumor (PNET)
Atypical teratoid/rhabdoid tumor (ATRT)

Question 9

Tumors originating from pituitary gland

Answer 9

Pituitary adenoma

Craniopharyngioma

Question 10

Tumors of cranial and peripheral nerves

Answer 10

Schwannoma
Neurofibroma
Malignant peripheral nerve sheath tumor (MPNST)

Question 11

How is the histological malignancy of brain tumors quantified?

Answer 11

WHO grading system: I-IV, IV is most aggressive

Question 12

Classic finding of pilocytic astrocytoma

Answer 12

Cyst with mural nodule in the cerebellum/brainstem of children and young adults. Histology shows long hair-like bipolar cells and Rosenthal fibers (eosinophilic corkscrew shaped bundle)

Question 13

What are the 4 levels of glioma grading?

Answer 13

1) Pleomorphism
2) Mitoses
3) Vascular proliferation
4) Necrosis

Question 14

Classic finding of glioblastoma

Answer 14

Lesion crossing the corpus callosum in butterfly shape with poorly defined borders, central necrosis, red/brown hemorrhage and cystic changes. CT shows ring enhancing mass.

Question 15

Describe the histological appearance of glioblastoma

Answer 15

Round, ribbon like areas of necrosis with psudopalisading

Question 16

Classic findings of oligodendroglioma

Answer 16

Calcified tumors of frontal lobe visible on CT. Histology shows perinuclear halos (“fried egg”) and chicken-wire capillary pattern. Neoplastic oligodendrocytes cluster around nuerons to form perineuronal satellitosis.

Question 17

Difference in appearance between medulloblastoma and retinoblastoma

Answer 17

Both have rosettes, but in MB the central core is composed of delicate neuropil fibrils (Homer-Wright) wheras in RB the cells are arranged around an empty lumen

Question 18

Classic findings of ependymoma

Answer 18

Most frequent in children, tumor in 4th ventricle causing hydrocephalus. On histology, tumor cells surround vessels to form perivascular pseudorosettes. Can also form true ependymal rosettes with central lumen.

Question 19

Classic findings of medulloblastoma

Answer 19

Malignant cerebellar tumor in children of neuroectodermal origin. Small blue cells with scanty cytoplasm and dark staining nuclei. MRI shows discrete contrast enhancing mass in the 4th ventricle.

Question 20

Classic findings of meningioma

Answer 20

Benign tumor of adults (F>M) arising from outside the brain parenchyma. MRI shows dural attachment. Histology shows psammoma bodies and whorls.

Question 21

Classic findings of craniopharyngioma

Answer 21

Benign childhood tumor deriving from Rathke’s pouch remnants. CT shows suprasellar mass with calcificaitons

Question 22

Classic findings of schwannoma

Answer 22

Cerebellopontine angle and CN VIII involvement causes loss of hearing and tinnitus. Found bilaterally in NF2. Yellow grossly due to lipid content. Shows alternating Antoni A (compact) and Antoni B (loose) structure with pallisades.

Question 23

Most common source for metastatic carcinoma to brain

Answer 23

Lung > Breast > Melanoma > Kidney > GI tract

Question 24

What is Neurofibromatosis type 1?

Answer 24

Familial tumor syndrome with c17 mutation leading to:
Neurofibromas, acoustic schwannomas, optic nerve gliomas, lisch nodules (iris) and cafe-au-lait spots (skin)

Plexiform neurofibroma = NF1

Question 25

What is Neurofibromatosis type 2?

Answer 25

Familial tumor syndrome with c22 mutation leading to bilateral acoustic schwannomas and multiple meningiomas

Question 26

What is tuberous sclerosis?

Answer 26

Familial tumor syndrome caused by c9 or c16 mutations leading to hamartomatous lesions in multiple organs.

Triad: adenoma sebaceum, seizures, mental retardation

Question 27

What is Von Hippel-Landau disease?

Answer 27

Familial tumor syndrome caused by c3 mutation of VHL tumor suppressor. Results in uncontrolled expression of VEGF leading to cerebellar hemangioblastomas. Seen with Renal cell carcinoma.