CNS Tumors

Question 1

Differentiate expansile from infiltrative growth

Answer 1

Expansile growth: sharp border between tumor and surrounding tissue

Infiltrative growth: Single tumor cells percolate through the brain parenchyma and surround normal structures

Question 2

How often do primary brain tumors metastasize outside of the CNS?

Answer 2

Almost never

Question 3

What are the three most common primary CNS tumors in adults?

Answer 3

Meningioma, schwannoma, glioblastoma

Question 4

What are the three most common primary CNS tumors in kids?

Answer 4

pilocytic astrocytoma (benign), ependymoma, medulloblastoma (highly malignant)

Question 5

What is the most common glioma?

Answer 5

Astrocytoma

Question 6

Where do astrocytomas appear in the brain?

Answer 6

Anywhere

Question 7

What age group is affected by astrocytomas?

Answer 7

All age groups

Question 8

Give an example of a grade I astrocytoma

Answer 8

Pilocytic astrocytoma

Question 9

What is the prognosis of a pilocytic astrocytoma?

Answer 9

Possibility of cure following surgical resection alone

Question 10

What is the identifying histologic cellular appearance of pilocytic astrocytomas?

Answer 10

Piloid cells with hair-like processes

Question 11

What is the identifying architecture of pilocytic astrocytomas?

Answer 11

Biphasic- alternating areas of compact and microcytic areas

Question 12

What are rosenthal fibers?

Answer 12

Characteristic red blobs found in pilocytic astrocytomas?

Question 13

What are the cancerous cells in glioblastomas?

Answer 13

Malignant astrocytes

Question 14

What is the characteristic appearance of glioblastoma on MRI?

Answer 14

Butterfly lesions- crosses the corpus callosum

Question 15

How do glioblastomas appear on CT?

Answer 15

Ring-enhancing mass

Question 16

What are the hyperplastic cells found in glioblastoma?

Answer 16

Endothelial cells- they are secreting VEGF and other growth factors.

Question 17

Glioblastoma tumor cells (astrocytes) are positive for what on IHC?

Answer 17

GFAP

Question 18

What is the prognosis for glioblastoma?

Answer 18

bad

Question 19

What is the most common presentation of an oligodendroma?

Answer 19

Frontal lobe mass- may present with seizures

Question 20

What are characteristic findings of an oligodendroglioma on CT?

Answer 20

intratumoral calcifications on CT

Question 21

Which tumors shows “fried eggs” cells and “chicken-wire” capillaries on HandE staining?

Answer 21

Oligodendrogliomas

Question 22

Describe the lumen of a homer-wright rosette (common in Medulloblastomas)

Answer 22

central pore is composed of delicate neuropil fibers

Question 23

From what cells do ependymomas arise?

Answer 23

Ependyma cells that line the walls of the ventricles and central canal of the spinal cord

Question 24

What is the most common side of an ependymoma?

Answer 24

4th ventricle –> hydrocephalus

Question 25

Where in the CNS do ependymomas typically arise in adults?

Answer 25

spinal cord

Question 26

Medulloblastomas arise from what type of cell?

Answer 26

Undifferentiated neuroectodermal cells

Question 27

Where do neuroectodermal cells arise?

Answer 27

cerebellum of children- highly malignant

Question 28

What is the treatment for medulloblastomas?

Answer 28

Sensitive to radiation therapy

Question 29

Describe the histology of a medulloblasotoma

Answer 29

Sheets of undifferentiated cells with scanty cytoplasm and dark staining nuclei

Question 30

Meningiomas arise from what type of cell?

Answer 30

usually arachnoid cells

Question 31

What is the malignancy of a meningioma? Prognosis?

Answer 31

Usually a benign tumor in adults- resection can be curative

Question 32

What are the characteristic histologic features of a meningioma?

Answer 32

Psammomas and whorls in middle aged girls

Question 33

What are craniopharyngiomas?

Answer 33

Benign tumors of childhood- often confused with pituitary adenomas-

Question 34

What are clinical presentations of craniopharyngiomas?

Answer 34

Endocrine dysfunction Visual symptoms Hydrocephalus Calcifications are common

Question 35

How do craniopharyngiomas appear on CT?

Answer 35

Suprasellar mass with calcifications

Question 36

What are schwannomas?

Answer 36

Benign tumors of schwann cell origin. Involved cranial or spinal nerves (often CN VIII)

Question 37

Bilateral acoustic neuromas are found in what disease?

Answer 37

Neurofibromatosis type 2

Question 38

What is the stain used in Schwannomas?

Answer 38

S100 protein (any cell of neural crest origin stain with S100 protein)

Question 39

What is the most common source of a metastatic tumor in the CNS?

Answer 39

lung

Question 40

What is the gene mutated in NF-1?

Answer 40

Gene on 17q11.2 Neurofibromin-GTPase activating protein

Question 41

What are pathognomonic findings for NF-1?

Answer 41

Plexiform neurofibromas - "bag of worms"

Question 42

What familial tumor syndrome presents with multiple cutaneous neurofibromas and cafe au lait spots?

Answer 42

NF-1

Question 43

What gene is mutated in NF-2?

Answer 43

chromosome 22q12 a tumor suppressor gene (merlin)

Question 44

What clinical symptom is associated with NF-2?

Answer 44

bilateral acoustic schwannomas and multiple meningiomas

Question 45

Hamartomatous lesions involving multiple organs are characteristic of what familial tumor syndrome?

Answer 45

Tuberous Sclerosis

Question 46

What is the classic triad of tuberous sclerosis?

Answer 46

Adenoma sebaceum Seizures Mental Retardation

Question 47

What are the two masses in brain in someone with tuberous sclerosis?

Answer 47

``` Tubers= glioneuronal hamartomas SEGAS= subependymal nodules --> hydrocephalus ```

Question 48

What is the CNS lesion associated with VHL?

Answer 48

CNS hemangioblastoma: highly vascularized

Question 49

Who is the hottest dude in our class?

Answer 49

Steven once he gets his kid jewelry off next Wednesday.