CNS

Question 1

What are histologic features of astrocytic tumors?

Answer 1

Grade 2: nuclear atypia only
Grade 3: nuclear atypia, focal or dispersed anaplasia, increased mitotic activity
Grade 4: microvascular proliferation, necrosis (and nuclear atypia, increased mitoses, but only the first two are pathognomonic for GBM).

Question 2

If a tumor is IDH wildtype, it is automatically GBM if one of the following is present:

Answer 2

• TERT promoter mutation
• EGFR amplification
• combined gain of entire chromosome 7 and loss of entire chromosome 10 [+7/-10]
• necrosis
• microvascular proliferation

Question 3

What are molecular biomarkers in CNS cancers

Answer 3

CDKN2A/B: homozygous deletion in IDH-mutant astrocytoma’s

GBM: automatically GBM if: TERT promoter mutation, EGFR amplification, +7/-10 copy number change

Question 4

Glioma and GBM systemic therapies:

Answer 4

LGG: adjuvant PCV x 6
AO: PCV x 6
AA: RT -> Adjuvant TMZ 150mg/m2 d1-5 q28d cycles x 12 cycles
GBM: CRT with concurrent TMZ 75mg/m2 EVERY DAY -> adjuvant TMZ 150mg/m2 d1-5 q28d cycles x 6 cycles

Question 5

Toxicity of WBRT/GBM treatment

Answer 5

ACUTE:
Alopecia (2nd to 3rd week)
Dermatitis
Fatigue
Transient worsening of symp d/t edema (esp 1st 2 wks)
N/V: esp brainstem
Otitis externa

LATE:
Alopecia (hair regrowth, if ever, 3-6m)
Telangectasias
RT necrosis
Diffuse leukoencephalopathy
Cerebral atrophy
Hearing loss
Retinopathy, cataract, visual change
Endocrine abnormality
Vasculopathy
Neurocog: decr new learning ability, short term memory, problem solving skills
2nd malignancy

Question 6

Pituitary adenoma management
1) management
2) LC with RT
3) what labs to monitor for

Answer 6

GTR -> OBS
If medically inoperable or recurrence not amendable to sx: 50/25 (CTV 0mm duh)
LC: 90%

Most common deficiency after RT: GH: monitor with IGF-1.
Others: TSH, prolactin, cortisol, if a female with amenorrhea then LH and FSH

Question 8

bitemporal hemaniopsia caused by
If lesion in left occipital what visual field deficit?

Answer 8

1) chiasm
2): right homonymous hemianopsia (right visual field loss)

Question 9

Hormones produced by pituitary:
1) anterior (6)
2) posterior (2)

Answer 9

1) LSH, FSH, TSH, ACTH, GH, prolactin
2) Oxytocin, ADH

Question 10

What are the indications for adjuvant radiation in pituitary adenomas/indications for post-op RT

Answer 10

Pituitary:
Non-functional: GTR-> observe. If SRT -> consider XRT on progression (this is benign, do not want 2% risk of 2ndary malignancy, this can be a GBM and the patient can die)

Functional:
XRT if unresectable, medically inoperable.
- IF functional, not controlled by medical management and recurrent after multiple surgeries then do XRT

DOSE: always say 54/30 or 50/25 do not say SRS for these hehe but if you need to know it, it is 15/1 non functional, 20/1 for functional

Question 11

What is a potentially fatal complication of macroadenoma if untreated

Answer 11

Pituitary apoplexy: due to acute ischemic infarct or hemhorrahge of the pituitary: causes bitemporal hemaniopsia, double vision, and pain

Question 12

Differential diagnosis for GBM (not including glioma)

Answer 12

Benign: Infection/abscess, AVM –arteriovenous malformation, Foreign body – ie: bullet, Hemorrhage/blood Multiple sclerosis (demyelinating plaque, Radiation necrosis
Malignant: Mets, Ependymoma, Germinoma, Schwannoma (acoustic neuroma), Pituitary adenoma, Primary CNS lymphoma, Meningioma, Choroid Plexus Tumors, Germ Cell Tumors

NOTE: DDX rim enhancing lesion: MAGIC DR:
M: etastasis
A: abscess
G: GBM
I: infarct
C: contusion

D: demyelinating (MS)
R: radiaiton necrosis

Question 13

What is PCV and what class of chemotherapies

Answer 13

Procarbazine: (alkylating agent)
CCNU: (aka lomustine): alkylating agent
Vincristine: vinca alkyloid

TMZ:also alkylating agent

Question 14

Question about dilantin:
1) side effects of dilantin:
2) what is the point of a loading dose

Answer 14

What are side effects of dilantin
1) N/V, abdominal pain, liver dysfunction, skin reaction, gingival hypertrophy
2) Achieve therapeutic level more quickly- need to monitor serum pheny level

Question 15

TMZ class and S/E

Answer 15

Alkylating agent! Thrombocytopenia, fatigue, nausea!!!!

Question 16

how to stabilize seizure

Answer 16

Lorazepam 4mg IV over 2 minutes (for status epilepticus)
Load with phenytoin and refer to neurology for AED of choice
Start AED (levetiracetam, lamotrigine, topiramate)

Question 17

3 reasons to do MRI brain 24 hours post op

Answer 17

• To assess for extent of resection (gross total vs subtotal with residual disease)/residual disease
• To assess resolution of previous findings: midline shift, cerebral edema
• To obtain imaging to prevent post-op changes from obscuring radiographic findings

Question 18

DDx posterior fossa mass (can say for both adult and peds)

Answer 18

BEAM:
brainstem glioma
Ependymoma
Astrocytoma: usually JPA
Medulloblastoma

ALSO: in adults: hemangioblastoma, lymphoma, mets
Benign: cyst, hematoma, abscess, infarct etc.

Question 19

When do give CSI
1) prophylactically (AKA always even when no visible disease)
2) for visible disease in spine

Answer 19

1) medulloblastoma, PNET
2) Ependymoma (if disseminated), pineal tumors, Germ cell tumors. Also for ALL prophylaxis

Question 20

Molecular features of oligo, astro

Answer 20

Both IDH mutated
- oligo: 1p19q co-deleted (almost always IDH1 mutated)
- Astro: CDKN2A/b: grade 4; ATRX, p53 mutant

Question 21

Meningoma genetic conditions

Answer 21

Tuberous sclerosis (give mTOR inhibitor), NF2 (also has bilateral schwannomas, spinal or intracranial meningomas, eye lesions, skin lesions), tuberous sclerosis

OTHER RFs: female, age, ionizing RT

Question 23

Risk factors for Gliomas and genetic syndromes.

Answer 23

Prior CNS radiation, fam history, genetic syndromes (NF1 and NF2, TS, li fraumeni, turcot)