Tumor

Question 1

Which of the following antihypertensive medications is most likely to cause unwanted vasodilation in a patient with severe traumatic brain injury?
Answers:
A. Nicardipine
B. Vasopressin
C. Clevidipine
D. Sodium Nitroprusside
E. Epinephrine

Answer 1

Sodium Nitroprusside

Discussion:
Sodium nitroprusside (SNP) exerts its antihypertensive effect by direct arteriolar vasodilation with no myocardial suppressive effects. In patients with compromised intracranial vascular compliance (ie. Severe traumatic brain injury), SNP results in cerebral arteriolar dilation with resultant elevations in intracranial pressure. Nicardipine and clevidipine are intravenous calcium channel blockers that are safely used to reduce blood pressure in neurosurgical patients. Epinephrine and vasopressin are hypertensive agents.
References:
Reference (1)
Cottrell JE, Patel K, Turndorf H, et al. Intracranial pressure changes induced by sodium
nitroprusside in patients with intracranial mass lesions. J Neurosurg. 1978 Mar;48(3):329-31.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/632856/
Reference (2)
Borrell-Vega J, Uribe AA, Palettas M, Bergese SD. Clevidipine use after first-line treatment failure
for perioperative hypertension in neurosurgical patients: A single-center experience. Medicine
(Baltimore). 2020 Jan;99(1):e18541. doi: 10.1097/MD.0000000000018541. PMID: 31895792;
PMCID: PMC6946217.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/31895792/

Question 2

Hemangioblastomas of the spinal cord are most likely to arise from an abnormality in which of the
following chromosomes?
Answers:
A. Chromosome 17
B. Chromosome 21
C. Chromosome 5
D. Chromosome 3
E. Chromosome 23

Answer 2

Chromosome 3

Discussion:
Hemangioblastomas have a well-known association with von Hippel-Lindau (VHL) disease with
mutations of the tumor suppressor gene VHL, which is found on chromosome 3. Approximately
20-33% of patients harboring a hemangioblatoma have Von Hippel-Lindau disease. Patients with
incidental hemangioblastomas should be screened for the presence of a pheochromocytoma via
urine analysis and CT of the abdomen prior to the undertaking of removal of their spinal cord
tumor. Genetic screening helps to confirm mutation of the VHL gene and lifetime followup
screening is required. Other potential tumors and their associated risk in VHL include: retinal
hemangioblastomas (~60%), cerebellar hemangioblastomas (44-72%), renall cell carcinoma
(25-60%), epididymal cystadenomas (25-60% of males), spinal cord hemangioblastomas
(13-50%), endolymphatic sac tumors (10-25%), brainstem hemangioblastomas (10-25%),
pheochromocytomas/paragangliomas (10-20%), pancreatic neuroendocrine tumors (9-17%),
broad ligament cystadenomas (10% of females). Commonly tested diseases on the other
chromosomes can include: 5 (Cri du chat syndrome), 17 (Charcot-Marie-Tooth), 21 (Down
syndrome), 23 (Turner syndrome)
References:
Maher ER, Kaelin WG Jr. von Hippel-Lindau disease. Medicine (Baltimore). 1997
Nov;76(6):381-91

Question 3

A 60-year-old man is evaluated because of progressive pain at the level of the sacrum. MR
imaging shows an 8-cm lesion within the sacrum consistent with a chordoma. Which of the
following treatment options will provide the best long-term outcome?
Answers:
A. Intralesional tumor decompression followed by referral for proton beam radiotherapy.
B. Proton beam radiotherapy alone without biopsy
C. CT guided biopsy of the lesion to confirm the diagnosis followed by referral for proton
beam radiotherapy.
D. CT guided biopsy of the lesion followed by en bloc resection of the lesion including
resection of the biopsy tract and referral for proton beam therapy.
E. CT guided biopsy of the lesion to confirm the diagnosis followed by referral for single
fraction stereotactic radiosurgery

Answer 3

CT guided biopsy of the lesion followed by en bloc resection of the lesion
including resection of the biopsy tract and referral for proton beam therapy

Discussion:
All sacral tumors must have proper histological confirmation prior to en bloc resection or
radiotherapy. Incisional biopsy or intralesional resection increases the risk of local recurrence of a
chordoma. Therefore, transcutaneous CT-guided trocar biopsy is preferred to open biopsy to
minimize the risk of contamination of normal tissues by tumor. The biopsy tract should be planned
to be included within the subsequent resection margins. En bloc resection of primary spine tumors
with disease-free margins (>1mm) when achievable provides the best long-term survival for
patients but recurrence still may be possible. Less than en bloc resection is associated with a high
recurrence rate even with radiation treatment. Proton beam radiotherapy or fractionated
stereotactic radiotherapy (1.8-2.4Gy fractions over 30 fractions or more, 60-70Gy total) allows for
the delivery of high treatment doses required for these tumors.
References:
Yamazaki T, McLoughlin GS, Patel S, et al. Feasibility and safety of en bloc resection for primary
spine tumors: a systematic review by the Spine Oncology Study Group. Spine (Phila Pa 1976).
2009 Oct 15;34(22 Suppl):S31-S38

Question 4

In children, the most common intramedullary spinal cord neoplasm is
Answers:
A. Astrocytoma
B. Hemangioblastoma
C. Ganglioglioma
D. Ganglioglioma
E. Ependymoma

Answer 4

Astrocytoma

Discussion:
Astrocytomas are the most common intramedullary tumor in the pediatric population accounting for
60% of these tumors. This is followed by ependymomas at 30% and developmental tumors at
approximately 4%.
References:
Steinbok P, Cochrane DD, Poskitt K. Intramedullary spinal cord tumors in children. Neurosurg Clin
N Am. 1992;3:931–945.

Question 5

Propofol infusion syndrome is most often associated with which of the following conditions?
Answers:
A. Metabolic alkalosis
B. Hyperglycemia
C. Rhabdomyolysis
D. Tachycardia
E. Hypokalemia

Answer 5

Rhabdomyolysis

Discussion:
Propofol infusion syndrome manifests as acute refractory bradycardia leading to asystole, in the
setting of one or more of the following: metabolic acidosis, rhabdomyolysis, hyperlipidemia, and
enlarged of fatty liver. Hyperkalemia is also often present, though hyperglycemia is not part of this
clinical syndrome. It is postulated to be the result of impaired mitochondrial oxidative pathway and
fatty acid metabolism. Risk factors include young age, severe respiratory or central nervous
system dysfunction, iatrogenic catecholamine or glucocorticoid administration, and insufficient
carbohydrate intake. Hemodialysis and supportive care are the mainstays of treatment.
References:
Reference (1)
Kam PC, Cardone D. Propofol infusion syndrome. Anaesthesia. 2007 Jul;62(7):690-701. doi:
10.1111/j.1365-2044.2007.05055.x. PMID: 17567345.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/17567345/
Reference (2)
Cremer, Olaf L. “The propofol infusion syndrome: more puzzling evidence on a complex and poorly
characterized disorder.” Critical care (London, England) vol. 13,6 (2009): 1012. doi:10.1186/cc8177
Pubmed Web link
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2811905/

Question 6

Which of the following components is most frequently overexpressed in malignant gliomas?
Answers:
A. BRAF V600E
B. EGFR
C. IDH2
D. 1p/19q
E. IDH1

Answer 6

EGFR

Discussion:
The correct answer is epidermal growth factor receptor (EGFR). EGFR is a receptor tyrosine
kinase that is amplified and overexpressed in 60%–90% of glioblastoma whereas only 7% of
glioblastoma demonstrate the IDH 1/2 mutation. The 1p/19 codeletion is the molecular signature
for oligodendroglioma, a histologic subtype of lower grade gliomas. Those with IDH1/2 mutations
carry a better prognosis than the 1p/19 codeleted IDHwt counterparts. The 1p/19q codeletion is
not found in glioblastoma. BRAF V600E mutant gliomas define a subset of histologic grade II
gliomas, not glioblastoma.
References:
Chandramohan V, Bao X, Keir ST, et al. Construction of an immunotoxin, D2C7-(scdsFv)-
PE38KDEL, targeting EGFRwt and EGFRvIII for brain tumor therapy. Clin Cancer Res. 2013 Sep
1;19(17):4717-27. doi: 10.1158/1078-0432.CCR-12-3891. Epub 2013 Jul 15. Eckel-Passow, J. E.,
Lachance, D. H., Molinaro, et al (2015). Glioma Groups Based on 1p/19q, IDH, and TERT
Promoter Mutations in Tumors. The New England journal of medicine, 372(26), 2499–2508.
https://doi.org/10.1056/NEJMoa1407279 Louis, D.N., Perry, A., Reifenberger, G. et al. The 2016
World Health Organization Classification of Tumors of the Central Nervous System: a summary.
Acta Neuropathol 131, 803–820 (2016). https://doi.org/10.1007/s00401-016-1545-1 Smith JS,
Perry A, Borell TJ, et al. Alterations of chromosome arms 1p and 19q as predictors of survival in
oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas. J Clin Oncol. 2000
Feb;18(3):636-45. doi: 10.1200/JCO.2000.18.3.636. PMID: 10653879. Louis DN, Ellison DW, Brat
DJ, et al. cIMPACT-NOW: a practical summary of diagnostic points from Round 1 updates. Brain
Pathol. 2019 Jul;29(4):469-472. doi: 10.1111/bpa.12732. Epub 2019 May 22. PMID: 31038238

Question 7

During radiosurgery, which of the following is a generally accepted upper limit of radiation
exposure to the optic chiasm?
Answers:
A. 6 Gy
B. 10 Gy
C. 3 Gy
D. 13 Gy
E. 20 Gy

Answer 7

10 Gy

Discussion:
The maximum tolerated single fraction maximum tolerated dose (MTD) to the optic nerve resulting
in optic neuropathy (ON) ranges from 8-12 Gy depending on the study and institution (Kirkpatrick
JP. J Radiosurg SBRT 2011; 1(2):95-107). One study shows 0% risk of ON with 10Gy, 27% at
10-15Gy and 78% at >15Gy during gamma knife treatment of middle cranial fossa lesions (Leber
KA, J Neurosurg. 1998 Jan;88(1):43-50.). However, this study lacks precision in the description of
the radiation modality. Another study suggested doses of <8Gy results in 0/35 patients developing
ON while doses >8Gy resulted in 4/17 patients developing ON (Tishler RB, Int J Radiat Oncol Biol
Phys. 1993 Sep 30;27(2):215-21). This study was criticized from planning being performed on CT
where it is difficult to visualize the optic nerves, max dosing could have been inaccurately
determined, and dosing fall off between 8 and 10Gy was only within a few millimeters. Fractionated
stereotactic radiosurgery planning uses a MTD to the optic nerve and chiasm of 60 Gy (55Gy from
the RTOG). The special somatic sensory nerves (optic, vestibulo-cochlear) are the most
susceptible to injury after high-dose, single-fraction radiation (radiosurgery). General somatic
nerves (oculomotor, trochlear, abducens, hypoglossal) are rarely affected by similar doses. The
afferent component of the trigeminal nerve (general somatic afferent) is intermediate in radiation
sensitivity. The length of cranial nerve that is irradiated and a prior history of radiation exposure are
also important factors related to cranial nerve injury after radiosurgery
References:
The maximum tolerated single fraction maximum tolerated dose (MTD) to the optic nerve resulting
in optic neuropathy (ON) ranges from 8-12 Gy depending on the study and institution (Kirkpatrick
JP. J Radiosurg SBRT 2011; 1(2):95-107). One study shows 0% risk of ON with 10Gy, 27% at
10-15Gy and 78% at >15Gy during gamma knife treatment of middle cranial fossa lesions (Leber
KA, J Neurosurg. 1998 Jan;88(1):43-50.). However, this study lacks precision in the description of
the radiation modality. Another study suggested doses of <8Gy results in 0/35 patients developing
ON while doses >8Gy resulted in 4/17 patients developing ON (Tishler RB, Int J Radiat Oncol Biol
Phys. 1993 Sep 30;27(2):215-21). This study was criticized from planning being performed on CT
where it is difficult to visualize the optic nerves, max dosing could have been inaccurately
determined, and dosing fall off between 8 and 10Gy was only within a few millimeters. Fractionated
stereotactic radiosurgery planning uses a MTD to the optic nerve and chiasm of 60 Gy (55Gy from
the RTOG). The special somatic sensory nerves (optic, vestibulo-cochlear) are the most
susceptible to injury after high-dose, single-fraction radiation (radiosurgery). General somatic
nerves (oculomotor, trochlear, abducens, hypoglossal) are rarely affected by similar doses. The
afferent component of the trigeminal nerve (general somatic afferent) is intermediate in radiation
sensitivity. The length of cranial nerve that is irradiated and a prior history of radiation exposure are
also important factors related to cranial nerve injury after radiosurgery.

Question 8

A 47-year-old man is evaluated because of a six-month history of right shoulder pain with tingling
into the right biceps and forearm. The pain is intractable despite a course of corticosteroids and
physical therapy. MR images are shown. Which of the following is the most appropriate next step
in management?
Answers:
A. Pain control and/or continued nerve blocks
B. Surgical stabilization alone and oncology referral
C. Surgical decompression and/or stabilization
D. Stereotactic radiosurgery
E. Bracing support and radiation therapy

Answer 8

Surgical decompression and/or stabilization

Discussion:
Metastatic spine disease here is likely impinging on the C5/6 nerve root resulting in compressive
radiculopathy. The patient seems to have failed conservative therapy and thus continuing it or
injections may not be helpful. Decompression of the nerve root with or without stabilization is
warranted. This would offer the best potential for long-term pain control and spine stability.
Radiation treatment would be used as an adjunct to decompression. The NOMS framework
approach has been a recent methodology to determine surgical treatment in oncology patients
(Laufer I. Oncologist 2013;18(6):744-751). Here a consideration of neurological function,
oncological response to treatment, mechanical stability of the spine, and systematic disease
burden are used to determine treatment approaches.
References:
Takami T, Naito K, Yamagat T, et al. Surgical Management of Spinal Intramedullary Tumors:
Radical and Safe Strategy for Benign Tumors. Neurol Med Chir (Tokyo). 2015 Apr;55(4):317-27.

Question 9

A 60-year-old woman is brought to the emergency department three weeks after undergoing
posterior fossa surgery at an outside institution. Over the past week, her family noticed severe
“restlessness,” characterized by constant, repetitive movements. The patient states that she was
given corticosteroids and an antiemetic at the outside hospital. Which of the following antiemetics
was the patient most likely prescribed?
Answers:
A. Diphenhydramine
B. Promethazine
C. Ondansetron
D. Metoclopramide
E. Dexamethasone

Answer 9

Metoclopramide

Discussion:
The patient in this clinical vignette has developed tardive dyskinesia in response to
metoclopramide, a dopamine (D2) receptor antagonist. Tardive dyskinesia is characterized by
choreoathetoid movements of the fingers, arms, legs, and trunk and stereotypical movements of
the mouth, face, and tongue. This rare side effect can be seen following administration of
dopamine receptor antagonists (ie. antipsychotic agents), and often persists following drug
cessation. The other anti-emetic agents listed here do not primarily exert anti-dopaminergic effects.
References:
Reference (1)
Click or tap here to enter text.MedlinePlus. US National Library of Medicine. Metoclopramide.
Available at: http://www.nlm.nih.gov/medlineplus/druginfo/meds/a684035.html. Last reviewed:
September 1, 2010. Accessed November 30, 2015.
Pubmed Web link
https://medlineplus.gov/druginfo/meds/a684035.html
Reference (2)
Limandri BJ. Tardive Dyskinesia: New Treatments Available. J Psychosoc Nurs Ment Health Serv.
2019 May 1;57(5):11-14. doi: 10.3928/02793695-20190410-02. PMID: 31042295.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/31042295/
Reference (3)
Rao AS, Camilleri M. Review article: metoclopramide and tardive dyskinesia. Aliment Pharmacol
Ther. 2010 Jan;31(1):11-9. doi: 10.1111/j.1365-2036.2009.04189.x. PMID: 19886950.

Question 10

A 41-year-old man is evaluated because of a 12-month history of progressive numbness of the
right arm and difficulty walking. Several years ago, he underwent cervical laminectomy to treat
similar symptoms. Physical examination shows hyperreflexia with two to three beats of clonus and
left upper extremity weakness. An MR image is shown. Which of the following is the most likely
diagnosis?
Answers:
A. Glioblastoma
B. Hemangioblastoma
C. Ganglioglioma
D. Astrocytoma
E. Ependymoma

Answer 10

Ependymoma

Discussion:
The most likely diagnosis in this patient is ependymoma. Ependymomas and astrocytomas are the
most common intramedullary spinal cord tumors, accounting for more than 90%. Among various
imaging features, the presence of syringohydromyelia is the only significant factor distinguishing
ependymoma from astrocytoma on multivariate analysis.
References:
Kucia EJ, Bambakidis NC, Chang SW, Spetzler RF. Surgical technique and outcomes in the
treatment of spinal cord ependymomas, part 1: intramedullary ependymomas. Neurosurg. 2011
Mar;68(1 Suppl Operative):57-63; discussion 63.

Question 11

Which of the following is the mechanism of action of benzodiazepines?
Answers:
A. N-methyl-D-aspartate (NMDA) antagonist
B. mu receptor activation
C. γ -aminobutyric acid B (GABAB) activation
D. γ -aminobutyric acid A (GABAA) activation
E. Glycine receptor activation

Answer 11

γ -aminobutyric acid A (GABAA) activation

Discussion:
Benzodiazepines activate γ -aminobutyric acid A (GABAA) neuronal receptors in the brain.
Benzodiazepines bind to an allosteric site on the GABAA receptor, which increases the receptors
affinity for the direct agonist GABA. The activated GABAA receptor is a chloride (Cl-) selective ion
channel that results in anion influx and hyperpolarization. This manifests clinically as anxiolytic,
amnestic, sedating, hypnotic, and anticonvulsant effects. Benzodiazepines exert no analgesic
activity. Amantadine functions as an NMDA receptor antagonist. GABAB is the target of baclofen
which is FDA approved for the treatment of muscle spasticity. Opiates function as mu receptor
agonists, which results in analgesia.
References:
Reference (1)
Barr J, Fraser GL, Puntillo K, Ely EW, Gélinas C, Dasta JF, Davidson JE, Devlin JW, Kress JP,
Joffe AM, Coursin DB, Herr DL, Tung A, Robinson BR, Fontaine DK, Ramsay MA, Riker RR,
Sessler CN, Pun B, Skrobik Y, Jaeschke R; American College of Critical Care Medicine. Clinical
practice guidelines for the management of pain, agitation, and delirium in adult patients in the
intensive care unit. Crit Care Med. 2013 Jan;41(1):263-306. doi:
10.1097/CCM.0b013e3182783b72. PMID: 23269131.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/23269131/
Reference (2)
Sigel E. Mapping of the benzodiazepine recognition site on GABA(A) receptors. Curr Top Med
Chem. 2002 Aug;2(8):833-9. doi: 10.2174/1568026023393444. PMID: 12171574.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12171574/

Question 12

A 10-year-old boy is evaluated because of a tumor in the pineal region. Measurement of CSF
tumor markers shows markedly increased levels of beta-human chorionic gonadotropin (B-hCG)
and alpha-fetoprotein (a-FP). Which of the following is the most likely diagnosis?
Answers:
A. choriocarcinoma
B. pineoblastoma
C. germinoma
D. teratoma
E. mixed germ cell

Answer 12

mixed germ cell

Discussion:
CSF profiles can aid in the diagnosis of certain pineal region tumors. Alpha-fetoprotein is
commonly elevated in endodermal sinus tumor, embryonal carcinoma, and immature teratoma,
and beta-human chorionic gonadotropin is commonly elevated in choriocarcinoma and mixed germ
cell tumors.
References:
Reference (1)
http://www.emedicine.com/Med/topic2911.htm
Reference (2)
Koh EJ, Phi JH, Park SH, Kim IO, Cheon JE, Wang KC, Cho BK, Kim SK. Mixed germ cell tumor
of the midbrain. Case Report. J Neurosurg Pediatr. 2009 Aug;4(2):137-42. doi:
10.3171/2009.3.PEDS08290. PMID: 19645547.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19645547/
Reference (3)
Fujimaki T. Central nervous system germ cell tumors: classification, clinical features, and treatment
with a historical overview. J Child Neurol. 2009 Nov;24(11):1439-45. doi:
10.1177/0883073809342127. PMID: 19841431.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19841431/

Question 13

Which of the following dorsal operative approaches offers the greatest operative corridor to the
anterior thoracic spine, to resect a thoracic vertebral body tumor, with vertebral body collapse and
anterior thoracic cord compression with resultant myelopathy?
Answers:
A. Costotransversectomy approach
B. Wide dorsal laminectomy
C. Anterior transsternal approach with cardiothoracic surgery
D. Extracavitary approach
E. Transpedicular approach

Answer 13

Extracavitary approach

Discussion:
Surgical approaches to the anterior thoracic spine are challenging due to the limited dorsal surgical
corridor. A dorsal laminectomy approach would offer a narrow operative corridor as retraction of
the thoracic cord is not well tolerated and reaching underneath the thecal sac would also be
limited. A transpedicular approach would allow for decompression of the ipsilateral vertebra body
and thecal sac but would offer a narrow corridor for contralateral vertebral resection. An anterior,
transsternal approach could be an option for high thoracic lesions but is very morbid with risks of
injury to the great vessels of the neck and heart. A posterolateral costotransversectomy approach
would require removal of the rip head and its articulation with the thoracic spine offering greater
access to the vertebral body. However, an extracavitary approach goes one step further with
greater resection of the rib and allows the greatest access to the anterior vertebral body. These
approaches re then thought of in terms of increasing levels of access. Instrumentation is required
for approaches that result in destabilization of the spine.
References:
Lubelski D, Abdullah KG, Mroz TE, et al. Lateral extracavitary vs. costotransversectomy
approaches to the thoracic spine: reflections on lessons learned. Neurosurgery. 2012
Dec;71(6):1096-102.

Question 14

A 53-year-old woman with a history of breast cancer is evaluated for lower extremity weakness
that developed within the past 24 hours. An MR image is shown. Which of the following treatment
strategies should be offered to the patient?
Answers:
A. External beam radiation therapy
B. Laminectomy
C. Circumferential decompression with instrumentation/fusion
D. Laminectomy and posterior fusion
E. Stereotactic radiosurgery

Answer 14

Circumferential decompression with instrumentation/fusion

Discussion:
The patient presents with potential neurological compromise secondary to a compressive lesion.
Treatment with embolization alone or in combination with radiation therapy or radiosurgery,
however, is not appropriate in this case due to both the neurologic deficit. Decompression followed
by oncological treatment would be warranted. Patchell et al demonstrated, in a randomized
controlled trial, that circumferential decompression followed by radiation provides better outcome
than radiation therapy alone (Patchetl RA. Lancet 2015;366(9486):634-8). The study was halted
after an interim analysis due to substantial clear benefit to the surgery with radiation group
compared to radiation alone. The NOMS framework approach has been a recent methodology to
determine surgical treatment in oncology patients (Laufer I. Oncologist 2013;18(6):744-751).
References:
Patchell RA, Tibbs PA, Regine WF, et al. Direct decompressive surgical resection in the treatment
of spinal cord compression caused by metastatic cancer: a randomised trial. Lancet. 2005 Aug
20-26;366(9486):643-8.

Question 15

A 34-year-old man presents with a progressive thoracic myelopathy. The MR image shown depicts
a mural nodule with an associated cyst. The mural nodule enhances with gadolinium. Preoperative
hematocrit is 51%. Further testing is warranted to assess for which of the following syndromes?
Answers:
A. Parathryoid
B. Erythropoietin
C. Thyroxine
D. Cortisol
E. Angiotensinogen

Answer 15

Erythropoietin

Discussion:
Erythropoietin is secreted by up to 10% of hemangioblastomas, resulting in a secondary
polycythemia vera which increases the risk for cardiovascular disease including cerebrovascular
attacks.
Angiotensin secretion has been seen in metastatic hepatocellular carcinoma. ACTH secretion
resulting in increased serum cortisol levels has been seen with small-cell carcinoma and carcinoid.
Parathyroid secretion has been reported in squamous cell carcinoma. Hyperthyroidism has been
associated with a variety of neoplasms.
References:
Korf BR. The phakomatoses. Clinics in Dermatology. 2005;23:78-84.

Question 16

A 44-year-old left-handed woman presents with a one-month history of headache and three days
of speech difficulty, nausea, and vomiting. The T1 gadolinium-enhanced MR image is shown.
Which of the following studies is best to differentiate tumor from abscess?
Answers:
A. Cerebral angiography
B. MRI spectroscopy
C. MRI DWI/ADC
D. MRI T1 with gadolinium
E. MRI T2

Answer 16

MRI spectroscopy

Discussion:
MRI with gadolinium is not a good method for distinguishing between glioblastoma and cerebral
abscess as both can demonstrate a similar appearing enhancing rim. While most abscesses
restrict water diffusion up to 20% do not (Reddy). Likewise while most necrotic glioblastomas
demonstrate high water diffusivity some mimic abscesses with low water diffusivity (Reddy).
Therefore, DWI/ADC cannot reliably be used to differentiate glioblastoma from cerebral abscess
(Toh 2014). Conversely, MR spectroscopy has been shown to be highly effective for differentiating
glioblastoma from non neoplastic lesions such as abscess with a specificity of 0.96 (Mishra). MR
perfusion, an advanced imaging technique that is based varying degrees of cerebral blood volume,
has shown promise in differentiating glioblastoma from abscess but has processing limitations
(Holmes). While abscesses tend to demonstrate a more robust T2 hypointense rim, a 2012 study
by Toh demonstrated that the appearance was not significantly different and therefore T2 weighted
MRI alone cannot be used to differentiate abscess from glioblastoma. Cerebral angiography is not
a useful technique for diagnosing or differentiating glioblastoma from cerebral abscess.
References:
Reddy JS, Mishra AM, Behari S, Husain M, Gupta V, Rastogi M, Gupta RK. The role of diffusionweighted imaging in the differential diagnosis of intracranial cystic mass lesions: a report of 147
lesions. Surg Neurol. 2006 Sep;66(3):246-50; discussion 250-1. Toh CH, Wei KC, Chang CN, Ng
SH, Wong HF, Lin CP. Differentiation of brain abscesses from glioblastomas and metastatic brain
tumors: comparisons of diagnostic performance of dynamic susceptibility contrast-enhanced
perfusion MR imaging before and after mathematic contrast leakage correction. PLoS One. 2014
Oct 17;9(10):e109172. Mishra AM, Gupta RK, Jaggi RS, Reddy JS, Jha DK, Husain N, Prasad KN,
Behari S, Husain M. Role of diffusion-weighted imaging and in vivo proton magnetic resonance
spectroscopy in the differential diagnosis of ring-enhancing intracranial cystic mass lesions.
Holmes TM, Petrella JR, Provenzale JM. Distinction between cerebral abscesses and high-grade
neoplasms by dynamic susceptibility contrast perfusion MRI. AJR Am J Roentgenol. 2004
Nov;183(5):1247-52. J Comput Assist Tomogr. 2004 Jul-Aug;28(4):540-7. Toh CH, Wei KC, Chang
CN, Hsu PW, Wong HF, Ng SH, Castillo M, Lin CP. Differentiation of pyogenic brain abscesses
from necrotic glioblastomas with use of susceptibility-weighted imaging. AJNR Am J Neuroradiol.
2012 Sep;33(8):1534-8. Kendall & Schwartz. Principles of Neural Science. 4th ed.

Question 17

A patient undergoes surgery for the midline frontal tumor in the images shown. In addition to
histologic examination, which of the following findings is most likely to predict a favorable outcome
for this patient?
Answers:
A. pseudopalisading necrosis
B. CDK2 mutation
C. IDH wildtype status
D. TERT promoter mutation
E. 1p and 19q co deletion

Answer 17

1p and 19q co deletion

Discussion:
Oligodendrogliomas are rare, diffusely infiltrating tumors, arising in the white matter of cerebral
hemispheres, and displaying better sensitivity to treatment and prognosis than other gliomas.
Favorable prognostic factors are low-grade, combined loss of 1p/19q, younger age, good
performance status, and frontal localization. All other choices including CDK2 mutation,
pseudopalisading necrosis, TERT promotor mutation, and IDH wildtype status portend a poor
prognosis.
References:
Reference (1)
Smith JS, Perry A, Borell TJ, et al: Alterations of chromosome arms 1p and 19q as predictors of
survival in oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas. J Clinical Oncology
18: 636-645, 2000.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/10653879/
Reference (2)
Cairncross JG, Ueki K, Zlatescu C, et al: Specific genetic predictors of chemotherapeutic response
and survival in patients with anaplastic oligodendroglioma. J National Cancer Inst 90:1473-1479,
1998.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/9776413/
Reference (3)
Cairncross G, Macdonald D, Ludwin S, et al: Chemotherapy for anaplastic oligodendroglioma. J
Clinical Oncology 12:2013-2021, 1994.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/7931469/

Question 18

A 40-year-old man undergoes a complete surgical resection of a well-differentiated
oligodendroglioma with 1p and 19q codeletion. Which of the following is the most appropriate next
step in management?
Answers:
A. radiation
B. chemotherapy and radiation
C. chemotherapy
D. serial mri
E. clinical observation

Answer 18

chemotherapy and radiation

Discussion:
RTOG 9802 was a randomized controlled trial published by Buchner et al. in adult patients with
newly diagnosed low grade glioma. Patients after biopsy or subtotal resection were randomized to
either radiation alone versus radiation followed by six cycles of combination chemotherapy. They
found a survival benefit for combination radiation and chemotherapy in patients who underwent
subtotal resection for grade 2 glioma who were younger than 40 years of age, or all patients who
were 40 years of age or older. Neurocognitive testing did not find any worsening of mini-mental
state exam scores in either treatment group for up to 5 years after initiation of treatment. Clinical
observation or serial imaging is not appropriate given evidence to support treatment with
chemotherapy and radiation in this patient population.
References:
Reference (1)
Baumert BG, Stupp R. Is there a place for radiotherapy in low-grade gliomas? Adv Tech Stand
Neurosurgery. 2010; 35:159-82.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/20102114/
Reference (2)
Buckner, J. C. et al. Radiation plus Procarbazine, CCNU, and Vincristine in Low-Grade Glioma.
New England Journal of Medicine 374, 1344–1355 (2016).
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/27050206/
Reference (3)
Jhaveri J, et al. Is less more? Comparing chemotherapy alone with chemotherapy and radiation for
high-risk grade 2 glioma: an analysis of the National Cancer Data Base
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/29205287

Question 19

A 78-year-old man presents with unsteadiness and hearing loss in the right ear. MR images of the
internal auditory canal are shown. The tumor is followed initially, but shows growth on follow-up
imaging. The patient opts for treatment with radiosurgery. Which of the following is the most
appropriate dose prescription to the periphery of the enhancing tumor?
Answers:
A. 10 Gy
B. 14 Gy
C. 12 Gy
D. 18 Gy
E. 16 Gy

Answer 19

12 Gy

Discussion:
Stereotactic radiosurgery affords a low rate (4%) of facial neuropathy and a reasonable rate (60%)
of hearing preservation with margin doses of 12-13 Gy. At this dose, the facial nerve function is
reportedly very well preserved. Studies evaluating higher doses have found 8% facial dysfunction
at a mean marginal dose of 13.4 Gy (Rowe et.al.), 16% at 14 Gy (Matthieu et.al.), 33% at 17 Gy
(Rowe et.al.) and 50% at 15-16 Gy (Mallory et al. only evaluating 78% of all patients). Doses lower
than 12-13 Gy have been associated with less effective tumor control.
References:
Reference (1)
Chapter 259. In: Winn HR, ed. Youmans Neurological Surgery. Saunders.
Reference (2)
Régis J, Carron R, Park MC, et al. Wait-and-see strategy compared with proactive Gamma Knife
surgery in patients with intracanalicular vestibular schwannomas. J Neurosurg. 2010 Dec;113
Suppl:105-11
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/21121792/

Question 20

A 6-year-old boy is evaluated because of a six-week history of diplopia, gait ataxia, and
corticospinal tract dysfunction. Which of the following is the most likely diagnosis?
Answers:
A. ependymoma
B. brainstem glioma
C. astrocytoma
D. choroid plexus papilloma
E. medulloblastoma

Answer 20

brainstem glioma

Discussion:
Diffuse pontine gliomas classically present with cerebellar signs, lower cranial nerve deficits, and
motor/sensory changes. Signs of CSF obstruction are more uncommon in this brainstem glioma
subtype.
References:
Reference (1)
Berger MS, Prados MD. Textbook of Neuro-Oncology. Philadelphia: Elsevier Inc.; 2005: 627.
Reference (2)
Grimm SA, Chamberlain MC. Brainstem glioma: a review. Curr Neurol Neurosci Rep. 2013
May;13(5):346. doi: 10.1007/s11910-013-0346-3. PMID: 23512689.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/23512689/

Question 21

Which of the following benefits describes the rationale for administering amantadine to patients
with post-traumatic disorders of consciousness after severe traumatic brain injury?
Answers:
A. Decrease the rate of adverse events
B. Decrease the rate of late post traumatic seizures
C. Accelerate the rate of functional recovery
D. Improve memory function long-term
E. Decrease the rate of early post traumatic seizures

Answer 21

Accelerate the rate of functional recovery

Discussion:
A randomized controlled trial comparing placebo to amantadine after severe traumatic brain injury
demonstrated that amantadine accelerated the rate of functional recovery for patients in vegetative
and minimally conscious states. Patients receiving amantadine were reported to have improved
overall function; however, statistical analysis was not performed in this study. Amantadine did not
reduce the risk of late post traumatic seizures or decrease the risk of late post traumatic seizures.
Levetiracetam and phenytoin reduce the risk of early post-traumatic seizures following severe
traumatic brain injury.
References:
Reference (1)
Giacino JT, Whyte J, Bagiella E, Kalmar K, Childs N, Khademi A, Eifert B, Long D, Katz DI, Cho S,
Yablon SA, Luther M, Hammond FM, Nordenbo A, Novak P, Mercer W, Maurer-Karattup P, Sherer
M. Placebo-controlled trial of amantadine for severe traumatic brain injury. N Engl J Med. 2012 Mar
1;366(9):819-26. doi: 10.1056/NEJMoa1102609. PMID: 22375973.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/22375973/
Reference (2)
Kruer RM, Harris LH, Goodwin H, Kornbluth J, Thomas KP, Slater LA, Haut ER. Changing trends
in the use of seizure prophylaxis after traumatic brain injury: a shift from phenytoin to
levetiracetam. J Crit Care. 2013 Oct;28(5):883.e9-13. doi: 10.1016/j.jcrc.2012.11.020. Epub 2013
Apr 6. PMID: 23566730.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/23566730/

Question 22

Which of the following constitutes the customary radiation therapy regimen for glioblastoma?
Answers:
A. No adjuvant radiation is indicated
B. External-beam radiation to the tumor bed at 60Gy
C. Stereotactic radiosurgery to the tumor bed at 30Gy
D. Stereotactic radiosurgery to the tumor bed at 12Gy
E. Whole-brain radiation at 30Gy

Answer 22

External-beam radiation to the tumor bed at 60Gy

Discussion:
The correct answer is external-beam radiation to the tumor bed at 60Gy in thirty fractions.
Stereotactic radiosurgery for glioblastoma is controversial and is not considered standard of care,
although it may be used in selected patients especially at recurrence after fractionated therapies
have already been used. Whole-brain radiation is not indicated in the modern management of
glioblastoma due to significant morbidity from hippocampal injury. Regardless of extent of
resection, the standard of care for glioblastoma is postoperative adjuvant chemotherapy
(temozolamide) and fractionated radiotherapy at a dose of approximately 60Gy.
References:
The correct answer is external-beam radiation to the tumor bed at 60Gy in thirty fractions.
Stereotactic radiosurgery for glioblastoma is controversial and is not considered standard of care,
although it may be used in selected patients especially at recurrence after fractionated therapies
have already been used. Whole-brain radiation is not indicated in the modern management of
glioblastoma due to significant morbidity from hippocampal injury. Regardless of extent of
resection, the standard of care for glioblastoma is postoperative adjuvant chemotherapy
(temozolamide) and fractionated radiotherapy at a dose of approximately 60Gy

Question 23

A patient with erythrocytosis that is associated with headaches and ataxia is most likely to have
which of the following disorders?
Answers:
A. Neurofibromatosis type 1
B. Familial cerebral cavernous malformations
C. Neurofibromatosis type 2
D. Von Hippel-Lindau
E. Marie Charcot Tooth

Answer 23

Von Hippel-Lindau

Discussion:
The patient most likely has a cerebellar hemangioblastoma that can be associated with
polycythemia vera causing an erythrocytosis. Von Hippel-Lindau (VHL) is an autosomal dominant
disorder affecting the tumor suppressor VHL gene on chromosome 3. Patients may have CNS
hemangioblastomas, retinal hemangioblastomas, endolymphatic sac tumors, renal tumors,
epididymal cystadenomas, pancreatic tumors and adrenal tumors including pheochromocytomas.
Cerebellar hemangioblastomas are a rare cause of secondary polycythemia due to production of
erythropoietin (EPO). Neurofibromatosis type 1 and 2 are associated with cutaneous abnormalities
and CNS tumors due to mutations affecting chromosome 17 (NF1) and chromosome 22 (NF2).
Marie Charcot Tooth disease is an inherited motor and sensory neuropathy with the most common
mutation being in gene PMP22 on chromosome 17. Familial cerebral cavernous malformations
result most commonly from mutations of CCM1 or CCM2 genes on chromosome 7.
References:
Reference (1)
So CC, Ho LC. Polycythemia secondary to cerebellar hemangioblastoma. Am J Hematol. 2002
Dec;71(4):346-7. doi: 10.1002/ajh.10196. PMID: 12447970.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12447970/
Reference (2)
Gläsker S, Vergauwen E, Koch CA, Kutikov A, Vortmeyer AO. Von Hippel-Lindau Disease: Current
Challenges and Future Prospects. Onco Targets Ther. 2020;13:5669-5690. Published 2020 Jun
16. doi:10.2147/OTT.S190753
Pubmed Web link
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305855

Question 24

High-dose barbiturate therapy is initiated to control refractory elevated intracranial pressure in a
21-year-old man with a severe, diffuse axonal injury without a focal mass lesion. This therapy
places the patient at greatest risk of which of the following conditions?
Answers:
A. Hypertension
B. Hyperkalemia
C. Hypokalemia
D. Hyperthermia
E. Miosis

Answer 24

Hypokalemia

Discussion:
Barbiturate infusion is sometimes used to reduce brain metabolism in severe, refractory
intracranial pressure elevation. Side effects of barbiturate therapy include hypokalemia, hepatic
and renal dysfunction, hypotension, immunosuppression, and delayed return of consciousness.
Thiopental administration is associated with hypokalemia followed by rebound hyperkalemia
following barbiturate cessation. Hyperlipidemia is observed in propofol infusion syndrome.
Mydriasis and hypothermia can be seen in barbiturate toxicity, not miosis and hyperthermia.
References:
Reference (1)
Neil MJ, Dale MC. Hypokalaemia with severe rebound hyperkalaemia after therapeutic barbiturate
coma. Anesth Analg. 2009 Jun;108(6):1867-8. doi: 10.1213/ane.0b013e3181a16418. PMID:
19448214.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19448214/
Reference (2)
Lewis CB, Adams N. Phenobarbital. 2021 May 9. In: StatPearls [Internet]. Treasure Island (FL):
StatPearls Publishing; 2021 Jan–. PMID: 30335310.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/30335310/
Reference 3
Rangel-Castilla L, Gopinath S, Robertson CS. Management of intracranial hypertension. Neurol
Clin. 2008 May;26(2):521-41, x. doi: 10.1016/j.ncl.2008.02.003. Erratum in: Neurol Clin. 2008
Aug;26(3):xvii. Rangel-Castillo, Leonardo [corrected to Rangel-Castilla, Leonardo]. PMID:
18514825; PMCID: PMC2452989.

Question 25

Consists of sheets of similar cells with perinuclear halos
Answers:
A. N/A
B. Hemangioblastoma
C. Vestibular schwannoma
D. Oligodendroglioma
E. Astrocytoma

Answer 25

Oligodendroglioma

Discussion:
The perinuclear halo, sometimes referred to as the “chicken wire” appearance, on frozen section is
an artifact of the preparation process. Oligodendrogliomas also demonsrate a homogeneous
population of tumor cells with round nuclei and scant cytoplasm. 1p/19 co deletion is now a
requisite for this diagnosis. Hemangioblastomas are highly vascular and are described as having
closely packed, thin walled vessels and is associated with VHL (gene 3p). Diffuse strocytomas
have increased cellularity and nucelar atypia without sheets of similar cells. Vestibular
schwannomas have a biphasic pattern with Antoni A areas that pallisade around Verocay bodies
and separate areas of Antoni B.
References:
Fortin D, Cairncross GJ, Hammond RR. Oligodendroglioma: an appraisal of recent data pertaining
to diagnosis and treatment. Neurosurgery. 1999 Dec;45(6):1279-91; discussion 191. doi:
10.1097/00006123-199912000-00001. PMID: 10598694.

Question 26

A 57-year-old man is evaluated because of a large, right-sided frontal lesion in the lateral ventricle.
A specimen obtained on stereotactic biopsy shows oligodendroglioma. Results of histologic
examination are most likely to be confused with which of the following lesions?
Answers:
A. Neurocytoma
B. Glibolastoma
C. Ependymoma
D. PXA
E. Juvenile Pilocytic Astrocytoma

Answer 26

Neurocytoma

Discussion:
Central neurocytomas demonstrate neuronal differentiation and histologically appear similar to
oligodendrogliomas, which have a characteristic ‘fried-egg’ appearance. The cells are typically
uniform and round. Purely neuronal origin is suggested by biomarkers including synaptophysin and
neuronal specific enolase. Central neurocytomas are WHO Grade II lesions. Abundant mitoses are
characteristic of high-grade lesions, and pseudopalisading necrosis is characteristic of GBM.
Rosenthal fibers are characteristic of juvenile pilocytic astrocytomas.
References:
Limaiem F, Bellil S, Chelly I, et al. Extraventricular neurocytoma in a child mimicking
oligodrendroglioma: a diagnostic pitfall. Pathologica. 2009 Apr;101(2):105-7.
Klysik M, Gavito J, Boman D, et al. Intraoperative imprint cytology of central neurocytoma: The
great oligodendroglioma mimicker. Diagn Cytopathol. 2010 Mar;38(3):202-7.

Question 27

A 47-year-old woman has a focal motor seizure seven months after undergoing stereotactic
radiosurgery for metastatic breast cancer lesions. Today, an MR image of her head shows loss of
enhancement within the confines of the treated right frontal lobe lesion. Findings include a ring of
contrast enhancement in the right frontal lobe surrounding the treated tumor, and hyperintensity in
the right frontal lobe on T2-weighted MR image and FLAIR, which are consistent with edema. A
PET scan with FDG demonstrates hypometabolism within the right frontal lobe lesion. The lesion is
most likely which of the following?
Answers:
A. radiation induced neoplasm
B. tumor recurrence
C. Radiation necrosis
D. ischemia
E. intracranial hemorrhage

Answer 27

radiation induced neoplasm

Discussion:
The most likely diagnosis is radiation-induced neoplasm. Intracranial hemorrhage would have a
different appearance on MRI and would lack ring enhancement. Radiation necrosis is unlikely
given that the patient had an MRI without this parenchymal finding two years after treatment. An
ischemic event could have this appearance on MRI, but only several weeks after the presenting
ictus. Recurrent meningioma is unlikely because of the parenchymal location and ring enhancing
nature of the lesion. The criteria for a radiation-induced tumor include: 1) a latency interval
between delivery of the radiation and tumor development, 2) the tumor must arise in the irradiated
region, 3) the neoplasm must be histologically distinct from the original irradiated tumor, and 4) an
absence of a genetic predisposition for neoplastic transformation. Reports of secondary central
nervous system radiation-induced neoplasms after fractionated radiation therapy in the central
nervous system have been well documented, and it is thought that the risk of developing a
radiation-induced tumor is approximately one to three percent. Radiation-induced tumors have
been reported after stereotactic radiosurgery. The estimated risk of radiation-induced neoplasms
after radiosurgery is between 0.1 and 0.01 percent.
References:
Reference (1)
Loeffler JS, Niemierko A, Chapman PH. Second tumors after radiosurgery: tip of the iceberg or a
bump in the road? Neurosurgery. 2003;52:1436-1442.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12762888/
Reference (2)
Shamisa A, Bance M, Nag S, et al. Glioblastoma multiforme occurring in a patient treated with
gamma knife surgery. Case report and review of the literature. J Neurosurg. 2001;94: 816-21
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/11354416

Question 28

Most common intramedullary spinal cord tumor
Answers:
A. N/A
B. Hemangioblastoma
C. Astrocytoma
D. Vestibular schwannoma
E. Oligodendroglioma

Answer 28

Astrocytoma

Discussion:
Gliomas make up 80% of all intramedullary tumors, and of those, 60-70% are astrocytomas with
the majority of the remainder being ependymomas. Astrocytic spinal cord tumors are often WHO
grade I or II, although rarely they are higher grade. The mainstay of treatment is surgical resection.
Second line treatment includes radiation which may prolong survival. Chemotherapy is used but its
benefit is unclear. Oligodendrogliomas in the spinal cord are very rare. Hemangioblastomas can
result in spinal intramedullary tumors and are associated with von Hippel Lindau disease.
Meningiomas and metastases often cause extramedullary spinal masses.
References:
Samartzis D, Gillis CC, Shih P, O’Toole JE, Fessler RG. Intramedullary Spinal Cord Tumors: Part
I-Epidemiology, Pathophysiology, and Diagnosis. Global Spine J. 2015;5(5):425-435.
doi:10.1055/s-0035-1549029

Question 29

A 53-year-old woman with breast cancer is evaluated because of a six-month history of back pain
and difficulty balancing. Neurological examination shows myelopathy. Spinal imaging
demonstrates T4 metastatic epidural spinal cord compression. Which of the following is a
benefit of surgical decompression followed by radiation therapy compared to radiation therapy
alone?
Answers:
A. Improved ability to ambulate
B. Improved systemic oncological treatment
C. Improved ability to enter clinical trials
D. Unchanged bowel/bladder function from baseline
E. Pain freedom

Answer 29

Improved ability to ambulate

Discussion:
In patients without neurological deficit warranting surgical decompression or fusion, radiation
therapy alone can be used with great benefit. In patients with spinal cord compression, Patchell et
al demonstrated, in a randomized controlled trial, that circumferential decompression followed by
radiation provides better outcome than radiation therapy alone (Patchetl RA. Lancet
2015;366(9486):634-8). The study was halted after an interim analysis due to substantial clear
benefit to the surgery with radiation group compared to radiation alone. The trial randomized
patients with metastatic epidural spinal cord compression (MESCC) to surgery followed by
radiotherapy (n=50) or radiotherapy alone (n=51). Radiation on both groups was 10 fractions of
3Gy. The primary endpoint of ability to walk was better in the surgery + radiotherapy group (84%)
compared to radiotherapy alone (57%) (Odds ratio 6.1, 95% CI 2.0-19.8, p=0.001). Longer
retention of walking was also seen in the surgery + radiotherapy group (median 122 days vs. 13
days). Secondary outcomes of urinary continence, muscle strength, functional status, reduced
corticosteroid and opioid analgesia time were all seen in patients who underwent surgery followed
by radiotherapy. The findings of this study have been replicated by others.
References:
Patchell RA, Tibbs PA, Regine WF, et al. Direct decompressive surgical resection in the treatment
of spinal cord compression caused by metastatic cancer: a randomised trial. Lancet 2005; 366:
643–48. Klimo P, Thompson CJ, Kestle JRW, et al. A meta-analysis of surgery versus conventional
radiotherapy for the treatment of metastatic spinal epidural disease. Neuro-oncol 2005; 7: 64–76.

Question 30

Extraneural metastases from a medulloblastoma most commonly occur in which of the following
anatomic locations?
Answers:
A. Lung
B. Lymph node
C. Liver
D. Bone
E. Adrenal gland

Answer 30

Bone

Discussion:
Medulloblastoma is the most common brain tumor in children and 7-10% of patients will develop
extraneural metastases. Extraneural metastases can involve bone (85% of cases), bone marrow
(27%), lymph nodes (15%), lung (6%) and liver (6%).
References:
Reference (1)
Mazloom A, Zangeneh AH, Paulino AC. Prognostic factors after extraneural metastasis of
medulloblastoma. Int J Radiat Oncol Biol Phys. 2010 Sep 1;78(1):72-8. doi:
10.1016/j.ijrobp.2009.07.1729. Epub 2010 Feb 3. PMID: 20133080.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/20133080/
Reference (2)
Berger, M. S., Baumeister, B., Geyer, J. R., Milstein, J., Kanev, P. M., & LeRoux, P. D. (1991). The
risks of metastases from shunting in children with primary central nervous system tumors, Journal
of Neurosurgery, 74(6), 872-877.
Pubmed Web link
https://thejns.org/view/journals/j-neurosurg/74/6/article-p872.xml

Question 31

Which of the following conditions is most commonly associated with nocturnal back pain in children
and adolescents?
Answers:
A. Osteochondroma
B. Hemangioma
C. Osteoid osteoma
D. Osteoblastoma
E. Fibrous dysplasia

Answer 31

Osteoid osteoma

Discussion:
Pain is the most common presenting symptom with these tumors, and it is often described as a
dull ache that is unremitting and may gradually increase in intensity and persistence. The pain
tends to be worse at night and typically responds to salicylates and non-steroidal anti-inflammatory
medictions.
References:
Saccomanni, Bernardino. “Osteoid osteoma and osteoblastoma of the spine: a review of the
literature.” Current reviews in musculoskeletal medicine vol. 2,1 (2009): 65-7.
doi:10.1007/s12178-009-9047-6

Question 32

A 62-year-old woman with metastatic renal cell carcinoma presents with “unbearable” back pain
and lower extremity myelopathy after sustaining a fall. MR imaging of the spine depicting cancer
involvement of only one vertebral body is shown. Which of the following is the most appropriate
management of this lesion?
Answers:
A. Bracing support and radiation therapy
B. Tumor embolization alone
C. Radiation therapy alone
D. Surgical stabilization and oncology referral
E. Surgical decompression and radiation therapy

Answer 32

Surgical decompression and radiation therapy

Discussion:
Radiation therapy can be used as a single-modality treatment in patients with tumorigenic back
pain. This pattern of pain can often be endorsed from a patient in any position as opposed to
mechanical back pain which is worse with upright positions and may reflect spine instability. In
patients without neurological deficit warranting surgical decompression or fusion, radiation therapy
alone can be used with great benefit. In patients with spinal cord compression, Patchell et al
demonstrated, in a randomized controlled trial, that circumferential decompression followed by
radiation provides better outcome than radiation therapy alone (Patchetl RA. Lancet
2015;366(9486):634-8). The study was halted after an interim analysis due to substantial clear
benefit to the surgery with radiation group compared to radiation alone. The NOMS framework
approach has been a recent methodology to determine surgical treatment in oncology patients
(Laufer I. Oncologist 2013;18(6):744-751). Here a consideration of neurological function,
oncological response to treatment, mechanical stability of the spine, and systematic disease
burden are used to determine treatment approaches.
References:
1. Patchell RA, Tibbs PA, Regine WF, et al. Direct decompressive surgical resection in the
treatment of spinal cord compression caused by metastatic cancer: a randomised trial. Lancet.
2005 Aug 20-26;366(9486):643-8.2. Sciubba DM, Petteys RJ, Dekutoski MB, et al. Diagnosis and
management of metastatic spine disease. A review. J Neurosurg Spine. 2010 Jul;13(1):94-108.

Question 33

An HIV-positive 47-year-old man who has not responded to antitoxoplasmosis treatment
undergoes a brain biopsy. He develops postoperative nausea and headache, and is treated with
prochlorperazine and acetaminophen with codeine. Within several hours, he is tachycardic and
tachypneic with a temperature of 39.4°C (103°F), and labile blood pressure. His pupils are 5 mm
and reactive, and muscle tone is increased, although the examination is difficult because of
agitation. Follow-up CT imaging is negative for hemorrhage. Which of the following is the most
appropriate next step in management?
Answers:
A. Diphenhydramine
B. diazepam
C. chlorpromazine
D. Levodopa
E. Propanolol

Answer 33

Levodopa

Discussion:
The patient in this clinical vignette has developed neuroleptic malignant syndrome. Clinical
features required for diagnosis include exposure to dopamine antagonists or withdrawal of
dopaminergic stimulation, parkinsonism and fever. Secondary criteria include autonomic instability,
change in mental status, and elevation of creatine kinase. It can be precipitated by any medication
with an affinity to the D2 dopamine receptor (ie. Prochlorperazine). Risk factors include exhaustion,
dehydration, and agitation. Patients with CNS involvement of HIV are also at increased risk.
Treatment involves cessation of the antidopaminergic agent, administration of a dopaminergic
agent (ie. Levodopa), and supportive care. Dantrolene has also been used for treatment.
Propanolol, diphenhydramine, chlorpromazine, and diazepam may be used for the treatment of
serotonin syndrome.
References:
Reference (1)
Poston KL, Frucht SJ. Movement disorder emergencies. J Neurol. 2008 Aug;255 Suppl 4:2-13.
doi: 10.1007/s00415-008-4002-9. PMID: 18821080.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/18821080/
Reference (2)
Guinart D, Taipale H, Rubio JM, Tanskanen A, Correll CU, Tiihonen J, Kane JM. Risk Factors,
Incidence, and Outcomes of Neuroleptic Malignant Syndrome on Long-Acting Injectable vs Oral
Antipsychotics in a Nationwide Schizophrenia Cohort. Schizophr Bull. 2021 May 20:sbab062. doi:
10.1093/schbul/sbab062. Epub ahead of print. PMID: 34013325.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/34013325/

Question 34

The mechanism of action of temozolomide involves which of the following?
Answers:
A. Deposition of methyl groups on DNA guanine groups
B. Mitochondrial outer membrane permeabilization leading to caspase activation
C. Interstrand crosslinking of DNA adducts with propagation of DNA damage recognition
signals
D. Perforation of the bi-lipid cell membrane
E. Endoplasmic reticulum stress induced apoptosis

Answer 34

Deposition of methyl groups on DNA guanine groups

Discussion:
Temozolomide (TMZ) is an alkalating agent the deposits methyl groups on purine bases of DNA
resulting in cytotoxic lesion (O6-methylguanine) which results in cell death. However, these lesions
can be removed by methylguanine methyltransferase (MGMT) and therefore patients who have a
methylated promoter of MGMT (inactive MGMT) have greater likelihood of tumor response to TMZ
compared to those who have an unmethylated MGMT promoter. Interstrand crosslinking of DNA is
the mechanism of action (MOA) of cisplatin. Endoplasmic reticulum stress is the MOA of
bevacizumab in certain cancers. Perforation of the cell membrane and mitochondrial outer
membrane permeabilization are other mechanisms of cellular apoptosis.
References:
Reference (1)
Zhang J, Stevens MF, Bradshaw TD. Temozolomide: mechanisms of action, repair and resistance.
Curr Mol Pharmacol. 2012 Jan;5(1):102-14. doi: 10.2174/1874467211205010102. PMID:
22122467.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/22122467/
Reference (2)
Stupp et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. NEJM.
2005.
Pubmed Web link
https://www.nejm.org/doi/full/10.1056/nejmoa043330

Question 35

A 40-year-old woman is evaluated because of a six-month history of progressive hearing loss in
the right ear. A contrast-enhanced MR image is shown. Radiosurgery is planned to treat the tumor.
This patient is most likely to have which of the following neurological deficits after radiosurgery?
Answers:
A. hearing loss
B. swallowing difficulty
C. face numbness
D. diplopia
E. facial weakness

Answer 35

hearing loss

Discussion:
The most likely complication after vestibular schwannoma radiosurgery is hearing loss. As a less
invasive alternative to surgical resection, stereotactic radiosurgery has been utilized increasingly
over the past 20 years for patients with vestibular schwannomas. Preservation of useful hearing
(speech discrimination scores greater than 50% and a pure tone average less than 50 dB) is
possible in approximately 60 percent of patients after radiosurgery. Facial weakness or numbness
occurs in less thanfour percent of patients. Diplopia or swallowing difficulty is rare. In large
radiosurgical series, the need for later tumor resection has been less than five percent.
References:
Reference (1)
Flickinger JC, Kondziolka D, Niranjan A, et al. Acoustic neuroma radiosurgery with marginal tumor
doses of 12 to 13 Gy. Int J Radiation Oncologic Biology Phys. 2004 Sep 1; 60(1):225-30.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/15337560/
Reference (2)
Regis J, Pellet W, Delsanti C, et al. Functional outcome after gamma knife surgery or microsurgery
for vestibular Schwannomas. J Neurosurgery 2002; 97:1091-1100
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12450031/

Question 36

Craniospinal radiotherapy is most appropriate to treat which of the following tumors?
Answers:
A. glioblastoma
B. pontine glioma
C. pilocytic astrocytoma
D. ependymoma grade 1
E. medulloblastoma

Answer 36

medulloblastoma

Discussion:
Medulloblastoma comprises a biologically heterogeneous group of embryonal tumours of the
cerebellum. Treatment includes surgical resection of the tumor, craniospinal irradiation and
chemotherapy, in addition to clinical trial evaluation focusing on disease biology and molecular
stratification. WHO Grade I ependymomas and pilocytic astrocytomas are typically treated with
surgical resection alone, and are associated with favorable clinical outcomes. Standard
radiotherapy treatment for pontine glioma is conventionally fractionated local field radiotherapy
with dose range of 54-60 Gy for a period of 6 weeks. Craniospinal irradiation is not standard
therapy for glioblastoma.
References:
Reference (1)
Packer RJ, Cogen P, Vezina G, Rorke LB. Medulloblastoma: clinical and biologic aspects. Neuro
Oncol. 1999 Jul;1(3):232-50. Review.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/11550316/
Reference (2)
Rutkowski S, Gerber NU, von Hoff K, et al. German Pediatric Brain Tumor Study Group. Treatment
of early childhood medulloblastoma by postoperative chemotherapy and deferred radiotherapy.
Neuro Oncol. 2009 Apr;11(2):201-10.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/18818397/

Question 37

Which of the following primary tumors has the greatest propensity to metastasize to the brain?
Answers:
A. Melanoma
B. Breast adenocarcinoma
C. Prostate adenocarcinoma
D. Lung squamous cell carcinoma
E. Colon adenocarcinoma

Answer 37

Melanoma

Discussion:
Melanoma is the 6th most common cancer in the U.S. among adults and has the highest
propensity to metastasize to the brain. Up to 75% of patients who die from melanoma have brain
metastases and in 50% of cases the cause of death is brain metastases. Lung, breast and colon
cancer are common brain metastases encountered in practice due to the high incidence of these
cancer types. Prostate cancer often metastasizes to bone so skull and spine mets are much more
common compared to brain metastases. The prognosis associated with melanoma including
patients with brain metastases has improved due to treatment options with BRAF inhibitors and
immunotherapy. 50-60% of patients demonstrate response of intracranial brain mets to treatment
with immunotherapy.
References:
Reference (1)
Barnholtz-Sloan, Jill S., et al. “Incidence proportions of brain metastases in patients diagnosed
(1973 to 2001) in the Metropolitan Detroit Cancer Surveillance System.” Journal of clinical
oncology 22.14 (2004): 2865-2872.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/15254054/
Reference (2)
Paul W. Sperduto, Wen Jiang, Paul D. Brown, Steve Braunstein, Penny Sneed, Daniel A. Wattson,
Helen A. Shih, Ananta Bangdiwala, Ryan Shanley, Natalie A. Lockney, Kathryn Beal, Emil Lou,
Thomas Amatruda, William A. Sperduto, John P. Kirkpatrick, Norman Yeh, Laurie E. Gaspar, Jason
K. Molitoris, Laura Masucci, David Roberge, James Yu, Veronica Chiang, Minesh Mehta,
Estimating Survival in Melanoma Patients With Brain Metastases: An Update of the Graded
Prognostic Assessment for Melanoma Using Molecular Markers (Melanoma-molGPA),
International Journal of Radiation OncologyBiologyPhysics,
Volume 99, Issue 4,
2017
Pubmed Web link
https://www.sciencedirect.com/science/article/pii/S0360301617335204#bib3

Question 38

In the early treatment of status epilepticus, intravenous administration of lorazepam (Ativan) is
preferable to intravenous administration of diazepam (Valium) for which of the following reasons?
Answers:
A. Diazepam is associated with an increased frequency of adverse events
B. Diazepam is reduces the efficacy of fosphenytoin
C. Lorazepam results in fewer seizure recurrences
D. Lorazepam is more effective at terminating seizures
E. Diazepam has a longer duration of action

Answer 38

Lorazepam results in fewer seizure recurrences

Discussion:
Current guidelines recommend the administration of benzodiazepines as a first line agent for the
early treatment of status epilepticus. Lorazepam and diazepam are equally effective at terminating
seizures. However, lorazepam results in fewer seizure recurrences and is less likely to require
repeat doses. The rate of adverse events between intravenous diazepam and lorazepam are
similar. Lorazepam has a longer duration of action than diazepam. Benzodiazepines and
fosphenytoin are often administered at the same time to treat status epilepticus. Both diazepam
and fosphenytoin are cleared by CY- enzymes in the liver.
References:
Reference (1)
Cock HR, Schapira AH. A comparison of lorazepam and diazepam as initial therapy in convulsive
status epilepticus. QJM. 2002 Apr;95(4):225-31. doi: 10.1093/qjmed/95.4.225. PMID: 11937649.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/11937649/
Reference (2)
Glauser, Tracy et al. “Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in
Children and Adults: Report of the Guideline Committee of the American Epilepsy Society.”
Epilepsy currents vol. 16,1 (2016): 48-61. doi:10.5698/1535-7597-16.1.48
Pubmed Web link
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4749120/

Question 39

A dysembryoplastic neuroepithelial tumor is most likely to be found in which of the following
locations?
Answers:
A. Insula
B. Occipital lobe
C. Cerebellum
D. Frontal lobe
E. Temporal lobe

Answer 39

Temporal lobe

Discussion:
Dysembryoplastic neuroepithelial tumor (DNET) is a WHO grade I lesion that has glioneuronal
elements and can be associated with cortical dysplasias. They are most commonly found in the
temporal lobe (50-80%) followed by the frontal lobe. DNETs can account for 20% of medically
refractory epilepsy. They are usually well circumscribed on imaging with a “bubbly” appearance
and are hyperintense on T2 with patchy enhancement on T1 post contrast imaging.
References:
Reference (1)
Thom M, Toma A, An S, et al. One hundred and one dysembryoplastic neuroepithelial tumors: an
adult epilepsy series with immunohistochemical, molecular genetic, and clinical correlations and a
review of the literature. J Neuropathol Exp Neurol. 2011; 70: 859-878
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/21937911/
Reference (2)
Luzzi S, Elia A, Del Maestro M, Elbabaa SK, Carnevale S, Guerrini F, Caulo M, Morbini P, Galzio
R. Dysembryoplastic Neuroepithelial Tumors: What You Need to Know. World Neurosurg. 2019
Jul;127:255-265. doi: 10.1016/j.wneu.2019.04.056. Epub 2019 Apr 11. PMID: 30981794.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/30981794

Question 40

A 5-year-old child with headaches and vomiting has a head circumference at the 95th percentile. A
cranial MR scan shows enlargement of the lateral and third ventricles and a 10 × 12-mm midline
lesion consistent with a tectal plate glioma. Which of the following is the most appropriate
management?
Answers:
A. Craniotomy for resection of the tumor
B. Endoscopic third ventriculostomy with biopsy
C. Endoscopic third ventriculostomy without biopsy
D. Insertion of ventriculoperitoneal shunt
E. Radiation and chemotherapy alone

Answer 40

Endoscopic third ventriculostomy without biopsy

Discussion:
The correct answer is ETV without biopsy. Acquired hydrocephalus from aqueductal stenosis due
to a benign process such as tectal glioma is the ideal indication for endoscopic third
ventriculostomy. ETV is preferred over even cranial CSF shunt insertion not only because of the
frequent complications of infection, obstruction, and excessive CSF drainage but also because of
the severe midbrain syndrome that can accompany shunt obstruction in the setting of tectal
glioma. The diagnosis of tectal glioma is based on typical imaging. The tumor is often not
appreciated on computed tomography, although faint calcifications are sometimes seen, as in this
case. Detection of tectal glioma is one reason that magnetic resonance imaging is indicated for all
patients with new diagnosis of aqueductal stenosis by CT scanning. On MR imaging the expansion
of the tectum has indistinct borders. The tumor is isointense on T1-weighted sequences and
slightly hyperintense on T2-weighted and FLAIR sequences. There is generally little or no
abnormal contrast enhancement. Biopsy is not necessary. Tectal gliomas generally follow a very
indolent clinical course over many years. Imaging surveillance is indicated, and treatment is
deferred unless or until the tumor enlarges. The treatment then is conformal radiotherapy or
stereotactic radiosurgery.
References:
Cinalli G, Sainte-Rose C, Simon I, Lot G, Sgouros S: Sylvian aqueduct syndrome and global
rostral midbrain dysfunction associated with shunt malfunction. J Neurosurg. 90:227-236, 1999.
Pollack IF, Pang D, Albright AL: The long-term outcome in children with late-onset aqueductal
stenosis resulting from benign intrinsic tectal tumors. J Neurosurg 80:681-688, 1994. Wellons JC,
3rd, Tubbs RS, Banks JT, Grabb B, Blount JP, Oakes WJ, et al: Long-term control of
hydrocephalus via endoscopic third ventriculostomy in children with tectal plate gliomas.
Neurosurgery. 51:63-67; discussion 67-68, 2002

Question 41

A 28-year-old woman who has been taking prednisone for asthma begins phenytoin treatment for
a newly diagnosed seizure disorder. On follow-up, she reports seizure cessation, but worsened
asthma. Which of the following is the most likely cause of the exacerbation of this patient’s
asthma?
Answers:
A. Increased enzymatic clearance of prednisone
B. Glutamate occupancy by prednisone
C. Phenytoin induced irritation of alveoli
D. Glucocorticoid receptor occupancy by phenytoin
E. Cross binding of prednisone and phenytoin

Answer 41

Increased enzymatic clearance of prednisone

Discussion:
Phenytoin increases the enzymatic clearance of prednisone and prednisolone. Phenytoin has
been reported to alter the pharmacokinetics of a large number of drugs. The majority of these
interactions arise because phenytoin is a potent inducer of cytochrome P450 microsomal
enzymes, and therefore may increase the clearance of drugs which are extensively metabolised;
drugs affected include carbamazepine, theophylline, methadone, prednisolone, dexamethasone,
metyrapone and several cardiac antiarrhythmic agents. Therefore, steroid doses may need to be
increased when administered with phenytoin. Phenytoin binds to voltage gated sodium channels. It
induces P450 and CYP34A and CYP2C9 enzymes. Prednisone binds to glucocorticoid receptors.
The drugs do not cross bind and phenytoin does not directly affect the alveoli.
References:
Reference (1)
Petereit LB, Meikle AW. Effectiveness of prednisolone during phenytoin therapy. Clin Pharmacol
Ther. 1977 Dec;22(6):912-6. doi: 10.1002/cpt1977226912. PMID: 923186.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/923186/
Reference (2)
Puckett Y, Gabbar A, Bokhari AA. Prednisone. [Updated 2021 Apr 19]. In: StatPearls [Internet].
Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:
https://www.ncbi.nlm.nih.gov/books/NBK534809/
Pubmed Web link
https://www.ncbi.nlm.nih.gov/books/NBK534809/
Reference (3)
Nation RL, Evans AM, Milne RW. Pharmacokinetic drug interactions with phenytoin (Part I). Clin
Pharmacokinet. 1990 Jan;18(1):37-60. doi: 10.2165/00003088-199018010-00003. PMID:
2178849.

Question 42

Which of the following most clearly distinguishes recurrent brain tumor from radiation necrosis?
Answers:
A. CT perfusion
B. MR perfusion
C. Functional MRI
D. Transcranial doppler
E. Nuclear medicine study

Answer 42

MR perfusion

Discussion:
Radiation necrosis is commonly seen in patients with gliomas or brain metastases treated with
radiation. Radiation necrosis (RN) is often a growing, contrast enhancing lesion on imaging which
makes it difficult to distinguish from true tumor progression. All imaging modalities have limitations
in distinguishing between RN and tumor progression. On conventional MRI RN tends to have less
of a nodular and dark grey appearance on T2. MR perfusion allows analysis of the cerebral blood
volume (CBV). Tumor progression would have an elevated CBV compared to RN but special
algorithms are utilized to achieve a high sensitivity and specificity using MR perfusion. MR SPECT
and PET scans have also been described to increase the sensitivity and specificity of
distinguishing RN from tumor progression. fMRI, transcranial doppler and CT perfusion in general
are not utilized for this purpose. The gold standard is tissue sampling and pathologic analysis.
References:
Reference (1)
Shah, A.H., Snelling, B., Bregy, A. et al. Discriminating radiation necrosis from tumor progression
in gliomas: a systematic review what is the best imaging modality?. J Neurooncol 112, 141–152
(2013). https://doi.org/10.1007/s11060-013-1059-9
Pubmed Web link
https://link.springer.com/article/10.1007/s11060-013-1059-9
Reference (2)
Kim YH, Oh SW, Lim YJ, Park CK, Lee SH, Kang KW, Jung HW, Chang KH. Differentiating
radiation necrosis from tumor recurrence in high-grade gliomas: assessing the efficacy of 18F-FDG
PET, 11C-methionine PET and perfusion MRI. Clin Neurol Neurosurg. 2010 Nov;112(9):758-65.
doi:
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/20619531/

Question 43

A 47-year-old man is evaluated six months after undergoing stereotactic radiosurgical treatment
(SRS) to treat a vestibular schwannoma that was subtotally resected four years ago. The patient is
asymptomatic. An MR image was obtained before he underwent SRS (Figure A), and an MR
image was obtained today (Figure B). Which of the following is the most appropriate
management?
Answers:
A. Observation and repeat MR imaging
B. Administration of chemotherapy
C. Repeat radiosurgery
D. Fractionated irradiation
E. Surgical resection

Answer 43

Observation and repeat MR imaging

Discussion:
Stereotactic radiosurgery affords a low rate (4%) of facial neuropathy and a reasonable rate (60%)
of hearing preservation with margin doses of 12-13 Gy. Hearing preservation may be more likely in
patients for whom a lower dose is delivered to the cochlea. This is usually possible when the tumor
is smaller in volume. While the effects of stereotactic radiosurgery can begin to take effect after a
few weeks, it generally takes several months to a year to show any effect. The best course of
action is to reassure the patient and continue to watch the lesion with serial imaging.
References:
Reference (1)
Pollock BE. Neurosurgery. 2006 Feb; 58(2):241-8; discussion 241-8
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/16462477/
Reference (2)
Smith DR, Saadatmand HJ, Wu CC, Black PJ, Wuu YR, Lesser J, Horan M, Isaacson SR, Wang
TJC, Sisti MB. Treatment Outcomes and Dose Rate Effects Following Gamma Knife Stereotactic
Radiosurgery for Vestibular Schwannomas. Neurosurgery. 2019 Dec 1;85(6):E1084-E1094. doi:
10.1093/neuros/nyz229. PMID: 31270543; PMCID: PMC6855984.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/31270543/

Question 44

A 52-year-old woman is evaluated because of back pain and radicular pain. A T2-weighted sagittal
MR image of the lumbar spine is shown. Which of the following is the most appropriate next step in
management?
Answers:
A. Radiation therapy
B. Transcutaneous CT-guided biopsy
C. Observation
D. En bloc resection
E. Open biopsy

Answer 44

Transcutaneous CT-guided biopsy

Discussion:
The MRI appearance of this lesion is consistent with a chordoma. Because it is lobulated and in
the neural foramen, it can easiy be mistaken for a nerve sheath tumor such as a schwannoma.
Enhancement of chordomas generally is heterogeneous or poor, unlike schwannomas which can
have robust homogeneous enhancement. All sacral tumors must have proper histological
confirmation prior to en bloc resection or radiotherapy. Incisional biopsy or intralesional resection
increases the risk of local recurrence of a chordoma. Piecemeal excision, curettage, or open
biopsy only leads to the spread of the chordoma, which increases the rate of local recurrence and
decreases the length of disease-free survival. The correct next step is a CT-guided biopsy with
marking of the biopsy tract for excision during the definitive treatment, which is an en bloc excision.
External beam radiation is not a primary treatment modality for chordoma. Adjuvant radiation (e.g.
proton beam radiotherapy) after surgical resection is often recommended. En bloc resection of
primary spine tumors with disease-free margins is achievable and provides the best long-term
survival for patients. Less than en bloc resection is associated with an almost 100% tumor
recurrent rate, even after radiotherapy.
References:
Fourney DR, Gokaslan ZL. Current management of sacral chordoma. Neurosurg Focus. 2003 Aug
15;15(2):E9.

Question 45

Which of the following CNS tumors occurs most frequently in patients with neurofibromatosis type
1?
Answers:
A. Ependymoma
B. Optic pathway glioma
C. Vestibular schwannoma
D. Meningioma
E. Brainstem glioma

Answer 45

Optic pathway glioma

Discussion:
The correct answer is optic pathway glioma. The most common tumor in NF1 children is the opticpathway glioma. These are detected in approximately 15%-30% of patients with NF1. Brainstem
tumors are rare in patients with NF1. Optic pathway gliomas (OPGs) are generally
histopathologically benign tumors; the majority are pilocytic astrocytomas (WHO Grade I). Patients
with neurofibromatosis type 1 (NF1) are placed under surveillance with serial brain imaging due to
their predisposition for developing astrocytomas. Approximately 15% to 20% of children with NF1
develop an OPG. Children without neurofibromatosis may also develop OPGs, accounting for
about 5% of pediatric intracranial tumors. Initial clinical manifestations of OPGs include visual
disturbances, endocrine and/or hypothalamic dysfunction, and obstructive hydrocephalus.
OPGs associated with NF1 tend to follow a more benign course with fewer tumors progressing and
requiring treatment. Interventions should be planned with the goal of controlling neurological
sequelae of the tumor rather than complete removal of the mass due to the serious potential for
treatment related morbidity. Chemotherapy is frequently the primary treatment in patients with
visual deterioration. Upfront or even adjuvant radiation is avoided due to the increased rates of
growth hormone deficiency and neurocognitive consequences. Gross-total resection is not feasible
due to inevitable risk of hypothalamic damage and blindness. In patients with NF1 who develop an
OPG and present with obstructive hydrocephalus, surgical resection of the intraventricular or
exophytic portion is recommended to manage the obstructive hydrocephalus. If there is persistent
post-resection hydrocephalus, patients may require endoscopic fenestration of the septum and/or
insertion of a ventriculoperitoneal shunt. Because OPGs in children with NF1 can remain dormant
after surgical debulking, observation and follow-up with serial imaging is appropriate. Alternatively,
in high-risk patients who are young, surgical biopsy may be followed with adjuvant chemotherapy,
especially if there is no hydrocephalus. Chemotherapy can also subsequently be used for
symptomatic or progressive tumors.
References:
Brain Imaging, Case Review Series, Laurie A. Loevner, MD, Assistant Professor, Department of
Radiology, University of Pennsylvania Medical Center, Philadelphia, PA. Robert-Boire V, Rosca L,
Samson Y, et al. Clinical presentation and outcome of patients with optic pathway glioma. Pediatr
Neurol. 2017;75:55-60.
Goodden J, Pizer B, Pettorini B, et al. The role of surgery in optic pathway/hypothalamic gliomas in
children. J Neurosurg Pediatr. 2014;13:1-12. Al-Otibi M, Rutka JT, Neurosurgical implications of
neurfibromatosis Type 1 in children. Neurosurg Focus. 2006 Jan 15;20(1):E2. Rosser T, Packer
RJ. Intracranial neoplasms in children with neurofibromatois 1. J Child Neurol. 2002 Aug; 17(8):
630-7. Menor F, Marti-Bonmati L, Arana E, Povatos C, Cortina H. Neurofibromatosis type 1 in
children: MR imaging and follow-up studies of central nervous system findings. Eur J Radiol. 1998
Jan; 26(2): 121-31.

Question 46

Which of the following radiosurgical doses is most likely to provide tumor control and hearing
maintenance in a patient with a 1-cm vestibular schwannoma?
Answers:
A. 16 Gy
B. 12 Gy
C. 14 Gy
D. 10 Gy
E. 18 Gy

Answer 46

12 Gy

Discussion:
At the 12-13 Gy dose, the facial nerve function is reportedly very well preserved. Studies
evaluating higher doses have found 8% facial dysfunction at a mean marginal dose of 13.4 Gy
(Rowe et.al.), 16% at 14 Gy (Matthieu et.al.), 33% at 17 Gy (Rowe et.al.) and 50% at 15-16 Gy
(Mallory et al. only evaluating 78% of all patients). Doses lower than 12-13 Gy have been
associated with less effective tumor control.
References:
Reference (1)
Phi JH, Kim DG, Chung HT, Lee J, Paek SH, Jung HW. Cancer. 2009 Jan 15; 115(2):390-8.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19109818/
Reference (2)
Chopra R,Kondziolka D,Niranjan A,Lunsford LD,Flickinger JC. Long-term follow-up of acoustic
schwannoma radiosurgery with marginal tumor doses of 12 to 13 Gy. Int J Radiat Oncol Biol Phys.
2007; 68: 845–851.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/17379451/

Question 47

A 26-year-old man who is scheduled for resection of a cystic posterior fossa tumor undergoes
preoperative laboratory testing and results show increased hematocrit. Medical history includes
retinal surgery. Which of the following conditions is most likely in this patient?
Answers:
A. von Hippel lindau
B. Neurofibromatosis type 2
C. Sturge Weber
D. tuberous sclerosis
E. Neurofibromatosis type 1

Answer 47

von Hippel lindau

Discussion:
von Hippel-Lindau disease is an autosomal dominant neoplasia syndrome that results from a
germline mutation in the VHLgene on chromosome 3. Germline mutations in the VHL gene lead to
the development of several benign or malignant tumours, and cysts in many organ systems.
Affected individuals might develop CNS lesions including cerebellar, spinal cord, brainstem, nerve
root, and supratentorial haemangioblastomas, as well as retinal haemangioblastomas and
endolymphatic sac tumours. Visceral features of the disorder include renal cysts and carcinomas,
phaeochromocytomas, pancreatic cysts and neuroendocrine tumours, as well as epididymal and
broad ligament cystadenomas. VHL-related mutations can be associated with erythrocytosis,
increased RBC mass, elevated RBC count, hemoglobin, or hematocrit An increased hematocrit is
typically not seen in Tuberous sclerosis, Sturge Weber, NF1, or NF2.
References:
Reference (1)
Taylor, Mainprize, Rutka. Neurogenetic basis of pediatric neurosurgical conditions. In: Albright, et
al, eds. Principles and Practice of Pediatric Neurosurgery. 2nd ed. Thieme Medical Publishers, Inc;
2007: 82.
Reference (2)
Lonser RR, Glenn GM, Walther M, Chew EY, Libutti SK, Linehan WM, Oldfield EH. von HippelLindau disease. Lancet. 2003 Jun 14;361(9374):2059-67. doi: 10.1016/S0140-6736(03)13643-4.
PMID: 12814730.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12814730/

Question 48

Intravenously administered desmopressin counteracts bleeding through which of the following
mechanisms?
Answers:
A. Increased formation of von Willebrand factor (WVF) multimers
B. Increased platelet procoagulant activity and platelet dependent thrombin generation
C. Increased released of fibrinogen
D. Increased platelet aggregation
E. Increased Factor VIIa activity

Answer 48

Increased platelet procoagulant activity and platelet dependent thrombin
generation

Discussion:
1-deamino-8-d-arginine vasopressin (desmopressin [DDAVP]) reduces bleeding by increasing
platelet procoagulant activity and platelet dependent thrombin generation in patients with platelet
disorders. DDAVP also serves to increase the endothelial release of VWF, enhances platelet
adhesion, and reduces bleeding time. Current recommendations proposed by the Neurocritical
Care Society suggest a single dose (0.4 mcg/kg) of DDAVP for antiplatelet associated intracerebral
hemorrhage.
References:
Reference (1)
Colucci G, Stutz M, Rochat S, Conte T, Pavicic M, Reusser M, Giabbani E, Huynh A, Thürlemann
C, Keller P, Alberio L. The effect of desmopressin on platelet function: a selective enhancement of
procoagulant COAT platelets in patients with primary platelet function defects. Blood. 2014 Mar
20;123(12):1905-16. doi: 10.1182/blood-2013-04-497123. Epub 2014 Jan 17. PMID: 24443440.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/24443440/
Reference (2)
Loggini A, El Ammar F, Darzi AJ, Mansour A, Kramer CL, Goldenberg FD, Lazaridis C. Effect of
desmopressin on hematoma expansion in antiplatelet-associated intracerebral hemorrhage: A
systematic review and meta-analysis. J Clin Neurosci. 2021 Apr;86:116-121. doi:
10.1016/j.jocn.2021.01.017. Epub 2021 Feb 3. PMID: 33775314.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/33775314/

Question 49

Which of the following is a feature of pilocytic astrocytoma that is associated with a poor
prognosis?
Answers:
A. optochiasmatic location
B. rosenthal fibers
C. increased mitoses
D. endothelial proliferation
E. presence of BRAF mutation

Answer 49

optochiasmatic location

Discussion:
Pilocytic astocytomas are grade 1 tumors with a good prognosis. prognosis is correlated to extent
of resection and when the tumor is in the optochiasmatic region, a complete resection is often not
possible. Pathological features that carry a poor prognosis in other tumors, including frequent
mitoses and endothelial proliferation, are compatible with World Health Organization grade I
designation and favorable prognosis in cases of JPA. BRAF can occur in 70% of patients.
References:
Reference (1)
Fernandez C, Figarella-Branger D, Girard N, Bouvier-Labit C, Gouvernet J, Paz Paredes A, Lena
G. Pilocytic astrocytomas in children: prognostic factors–a retrospective study of 80 cases.
Neurosurgery. 2003 Sep;53(3):544-53; discussion 554-5. doi:
10.1227/01.neu.0000079330.01541.6e. PMID: 12943571.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12943571/
Reference (2)
Paixão Becker A, de Oliveira RS, Saggioro FP, Neder L, Chimelli LM, Machado HR. In pursuit of
prognostic factors in children with pilocytic astrocytomas. Childs Nerv Syst. 2010 Jan;26(1):19-28.
doi: 10.1007/s00381-009-0990-8. Epub 2009 Oct 13. PMID: 19823847.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19823847

Question 50

A 59-year-old man comes for evaluation of hearing loss. Evaluation shows high frequency
sensorineural hearing loss and near normal speech discrimination. An MR scan of the brain shows
a 10-mm uniformly enhanced mass within the internal auditory canal. Which of the following is the
most likely complication of stereotactic radiosurgery for this lesion?
Answers:
A. Facial weakness
B. Diplopia
C. Facial Numbness
D. Swallowing difficulty
E. Hearing loss

Answer 50

Hearing loss

Discussion:
The most likely complication after vestibular schwannoma radiosurgery is hearing loss. As a less
invasive alternative to surgical resection, stereotactic radiosurgery has been utilized increasingly
over the past 20 years for patients with vestibular schwannomas. Preservation of useful hearing
(speech discrimination scores greater than 50% and a pure tone average less than 50 dB) is
possible in approximately 60 percent of patients after radiosurgery. Facial weakness or numbness
occurs in less than four percent of patients. Diplopia or swallowing difficulty is rare. In large
radiosurgical series, the need for later tumor resection has been less than five percent.
References:
Reference (1)
Flickinger JC, Kondziolka D, Naranjan A, et al. Acoustic neuroma radiosurgery with marginal tumor
doses of 12 to 13 Gy. International J Radiation Oncology Biol Phys. 2004; 60:225-230.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/15337560/
Reference (2)
Regis J, Pellet W, Delsanti C, et al. Functional outcome after gamma knife surgery or microsurgery
for vestibular Schwannomas. J Neurosurgery 2002; 97:1091-1100
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/12450031/

Question 51

Which of the following veins is most commonly divided during resection of a pineal region tumor
using a supracerebellar approach?
Answers:
A. internal cerebral vein
B. posterior mesencephalic vein
C. vein of galen
D. basal vein of rosenthal
E. precentral cerebellar

Answer 51

precentral cerebellar

Discussion:
The left and right internal cerebral veins unite beneath the splenium of the corpus callosum to form
the great vein of Galen. The vein of Galen is a critical vein that drains most of the cerebral white
matter and deep gray nuclei. In the quadrigeminal cistern, the basal vein unites with the deep
cerebral veins to form the great vein of Galen, which then drains to the straight sinus and,
subsequently, the confluence of sinuses. The internal cerebral vein, together with the basal vein of
Rosenthal and their tributaries, form the deep cerebral venous system. None of these veins can be
can be ligated without significant morbidity. In the infratentorial supracerebellar approach, it is
necessary to divide some of the bridging veins, which can include the precentral cerebellar vein,
with low risk of neurologic compromise or cerebellar swelling.
References:
Reference (1)
Lozier AP, Bruce JN. Surgical approaches to posterior third ventricular tumors. Neurosurgery Clin
N America. 2003 Oct; 14(4): 527-545.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/15024799/
Reference (2)
Matsushima K, Yagmurlu K, Kohno M, Rhoton AL Jr. Anatomy and approaches along the
cerebellar-brainstem fissures. J Neurosurg. 2016 Jan;124(1):248-63. doi:
10.3171/2015.2.JNS142707. Epub 2015 Aug 14. PMID: 26274986.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/26274986/

Question 52

Vertebra plana is classically associated with which of the following spinal lesions?
Answers:
A. Chondrosarcoma
B. Aneurysmal bone cyst
C. Metastatic bone cancer
D. Eosinophilic granuloma
E. Osteoblastoma

Answer 52

Eosinophilic granuloma

Discussion:
Vertebra plana can be commonly caused by eosinophilic granuloma otherwise known as
Langerhan cell histiocytosis (LCH) or histiocytosis X, a proliferation of Langerhan cells and
abundance of eosinophils, lymphocytes, and neutrophils. These cells produce prostaglandins
which result in medullary bone resorption. LCH is commonly may be seen in the skull (~50%),
pelvis (23%), femur (17%), ribs (8%, most common in adults, humerus (7%), mandible (7%), or
spine (7%). Manifestations in the spine can be vertebra plana of the cervical or thoracic spine,
especially in pediatric patients, where the vertebral body has lost its entire height anteriorly and
posteriorly. Hand-Schuller-Christian disease describes when the disease is chronic and
disseminated in bone and viscera. Letterer-Siwe describes a fatal form that occurs in young
children. Various reported treatment options for LCH include observation, radiation, bracing,
indomethacin administration, surgical stabilization, corticosteroid injections, ablation, local excision,
and chemotherapy depending on the clinical situation. Other causes of vertebrae plana can be
identified from the mnemonic I MELT (infection, metastasis/myeloma, eosinophilic granuloma,
lymphoma/leukemia, trauma/tuberculosis).
References:
Bertram C, Madert J, Eggers C. Eosinophilic granuloma of the cervical spine. Spine (Phila Pa
1976). 2002 Jul 1;27(13):1408-13

Question 53

Which of the following clinical features is most characteristic of pontine brain-stem gliomas in
children?
Answers:
A. Anisocoria
B. Dysequilibrium/gait disturbance
C. Expressive aphasia
D. Absence seizure
E. Pill rolling tremor

Answer 53

Dysequilibrium/gait disturbance

Discussion:
The correct answer are the cerebellar signs of dysequilibrium and gait dysfunction. Diffuse pontine
gliomas classically present with cerebellar signs, lower cranial nerve deficits, and motor/sensory
changes. Signs of CSF obstruction are more uncommon in this brainstem glioma subtype.
Fibrillary astrocytoma is the most common histological type; although the genetic profile of
mutations is varied, frequently TP53 and loss of 22q heterozygosity are encountered. The Ki-67
index is usually not elevated.
References:
Kaplan AM, Albright AL, Zimmerman RA. Brainstem gliomas in children: A Children’s Cancer
Group review of 119 cases. Pediatr Neurosurg 1996; 24:1885. Louis DN, Ohgaki H, Wiestler OD.
WHO Classification of Tumours of the Central Nervous System. Lyon france, International Agency
for Research on Cancer, 2007. Wippold FJ. Neuropathology for the neuroradiologist: rosettes and
pseudorosettes. AJNR Am J. Neuroradiol. 2006. Mar;27(3):488-92

Question 54

Which of the following adverse outcomes has been linked to the administration of corticosteroids to
patients in the treatment of traumatic brain injury?
Answers:
A. Increased risk of catheter associated infection
B. Increased risk of mortality
C. Increased risk of acute kidney injury
D. Increased risk deep venous thrombosis
E. Increased risk of ventilator dependence

Answer 54

Increased risk of mortality

Discussion:
In patients with severe TBI, high-dose methylprednisone is associated with increased mortality and
is contraindicated; therefore, the use of steroids is not recommended to improve outcome or
control ICP.
References:
Reference (1)
Carney N, Totten AM, O’Reilly C, Ullman JS, Hawryluk GW, Bell MJ, Bratton SL, Chesnut R, Harris
OA, Kissoon N, Rubiano AM, Shutter L, Tasker RC, Vavilala MS, Wilberger J, Wright DW, Ghajar
J. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery.
2017 Jan 1;80(1):6-15. doi: 10.1227/NEU.0000000000001432. PMID: 27654000.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/27654000/
Reference (2)
Roberts I, Yates D, Sandercock P, Farrell B, Wasserberg J, Lomas G, Cottingham R, Svoboda P,
Brayley N, Mazairac G, Laloë V, Muñoz-Sánchez A, Arango M, Hartzenberg B, Khamis H,
Yutthakasemsunt S, Komolafe E, Olldashi F, Yadav Y, Murillo-Cabezas F, Shakur H, Edwards P;
CRASH trial collaborators. Effect of intravenous corticosteroids on death within 14 days in 10008
adults with clinically significant head injury (MRC CRASH trial): randomised placebo-controlled
trial. Lancet. 2004 Oct 9-15;364(9442):1321-8. doi: 10.1016/S0140-6736(04)17188-2. PMID:
15474134.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/15474134/

Question 55

A 78-year-old man presents with unsteadiness and hearing loss in the right ear. MR images of the
internal auditory canal are shown. The tumor is followed initially, but shows growth on follow-up
imaging. The patient opts for treatment with radiosurgery. Which of the following is the most
appropriate dose prescription to the periphery of the enhancing tumor?
Answers:
A. 16-17 Gy
B. 14-15
C. 12-13 Gy
D. 18-19 Gy
E. 10-11 Gy

Answer 55

12-13 Gy

Discussion:
Stereotactic radiosurgery affords a low rate (4%) of facial neuropathy and a reasonable rate (60%)
of hearing preservation with margin doses of 12-13 Gy. At this dose, the facial nerve function is
reportedly very well preserved. Studies evaluating higher doses have found 8% facial dysfunction
at a mean marginal dose of 13.4 Gy (Rowe et.al.), 16% at 14 Gy (Matthieu et.al.), 33% at 17 Gy
(Rowe et.al.) and 50% at 15-16 Gy (Mallory et al. only evaluating 78% of all patients). Doses lower
than 12-13 Gy have been associated with less effective tumor control.
References:
1. Chapter 259. In: Winn HR, ed. Youmans Neurological Surgery. Saunders.
2. Régis J, Carron R, Park MC, et al. Wait-and-see strategy compared with proactive Gamma
Knife surgery in patients with intracanalicular vestibular schwannomas. J Neurosurg. 2010 Dec;113
Suppl:105-11

Question 56

Which of the following antiseizure medications can be used safely in a patient with liver failure?
Answers:
A. Carbamazepine
B. Phenytoin
C. Phenobarbital
D. Valproic acid
E. Vigabatrin

Answer 56

Vigabatrin

Discussion:
Vigabatrin is an antiseizure medication that undergoes minimal metabolism and has never been
reported to cause drug induced liver injury. Phenytoin, carbamazepine, and valproic acid undergo
significant metabolism and should be avoided in liver failure. Phenobarbital undergoes a
combination of renal excretion and hepatic metabolism, and thus it may be used cautiously.
References:
Reference (1)
Kamitaki BK, Minacapelli CD, Zhang P, Wachuku C, Gupta K, Catalano C, Rustgi V. Drug-induced
liver injury associated with antiseizure medications from the FDA Adverse Event Reporting System
(FAERS). Epilepsy Behav. 2021 Apr;117:107832. doi: 10.1016/j.yebeh.2021.107832. Epub 2021
Feb 21. PMID: 33626490.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/33626490/
Reference (2)
Asconapé JJ. Use of antiepileptic drugs in hepatic and renal disease. Handb Clin Neurol.
2014;119:417-32. doi: 10.1016/B978-0-7020-4086-3.00027-8. PMID: 24365310.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/24365310/

Question 57

In patients with vestibular (acoustic) schwannomas, the facial (VII) nerve is usually found in which
of the following locations?
Answers:
A. Superior
B. Dorsal
C. Within the tumor
D. Ventral
E. Inferior

Answer 57

Ventral

Discussion:
Vestibular schwannomas (VS) commonly displace the facial nerve ventrally as they arise from the
posteriorly located vestibular nerves. The least likely location of the facial nerve is dorsal to the
tumor. The facial nerve enters the facial canal at the anterior superior quadrant of the meatus and
this is a good landmark to identify the nerve during surgical resection.
References:
Reference (1)
Rhoton AL Jr, Tedeschi H. Microsurgical anatomy of acoustic neuroma. Otolaryngol Clin North Am.
1992 Apr;25(2):257-94. PMID: 1630829.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/1630829/
Reference (2)
Kim HS, Kim DI, Chung IH, Lee WS, Kim KY. Topographical relationship of the facial and
vestibulocochlear nerves in the subarachnoid space and internal auditory canal. AJNR Am J
Neuroradiol. 1998 Jun-Jul;19(6):1155-61. PMID: 9672031.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/9672031

Question 58

Which of the following is the most appropriate management after complete resection of a mature
teratoma of the pineal region?
Answers:
A. Radiosurgery to the resection cavity
B. Fractionated local radiation therapy
C. Observation
D. Craniospinal irradiation
E. Chemotherapy

Answer 58

Observation

Discussion:
The correct answer is observation. Teratomas are relatively uncommon brain tumors which are
most often found in younger age groups. Most teratomas arise in the pineal or suprasellar regions.
Three pathological subtypes are described: mature, immature and malignant. Mature teratomas
are benign, slow growing lesions which can often be cured with a gross total surgical resection.
Immature or malignant teratomas, on the other hand, are often rapidly growing tumors which often
recur after resection and are resistant to most adjuvant therapies.
References:
Hunt SJ, Johnson PC, Coons SW, Pittman HW. Neonatal intracranial teratomas. Surg Neurol.
1990 Nov; 34(5):336-42.
Bavbek M, Altinors N, Caner H, Agildere M, Cinemre O, Guz T, Erekul S. Giant posterior fossa
teratoma. Childs Nervous System. 1999 Jul; 15(6-7):359-61.

Question 59

An otherwise healthy 50-year-old man has the findings shown in this thoracic axial CT scan and
sagittal MR image at the T4 level. Which of the following is the most likely diagnosis?
Answers:
A. Spine metastasis
B. Osteochondroma
C. Osteoid osteoma
D. Hemangioma
E. Chordoma

Answer 59

Hemangioma

Discussion:
Hemangiomas present a at a peak age of 30-50 years with a female predominance. Seventy-five
percent are spinal and usually present in the vertebral body. CT demonstrates a honeycomb
pattern or a “salt and pepper” appearance due to the involvement of thickened vertebral
trabeculae. MRI will demonstrate the hemangioma as fat and water and be hyperintense on T2-
weighted imaging.
References:
Pastushyn AI, Slin’ko EI, Mirzoyeva GM. Vertebral hemangiomas: diagnosis, management, natural
history and clinicopathological correlates in 86 patients. Surg Neurol. 1999;50 (6): 535-47.

Question 60

A 57-year-old man is evaluated because of a large, right-sided frontal lesion in the lateral ventricle.
A specimen obtained on stereotactic biopsy shows oligodendroglioma. Results of histologic
examination are most likely to be confused with which of the following lesions?
Answers:
A. Juvenile Pilocytic Astrocytoma
B. Glibolastoma
C. Pleomorphic xanthoastrocytoma
D. Central Neurocytoma
E. Ependymoma

Answer 60

Central Neurocytoma

Discussion:
Central neurocytomas demonstrate neuronal differentiation and histologically appear similar to
oligodendrogliomas, which have a characteristic ‘fried-egg’ appearance. The cells are typically
uniform and round. Purely neuronal origin is suggested by biomarkers including synaptophysin and
neuronal specific enolase. Central neurocytomas are WHO Grade II lesions. Abundant mitoses are
characteristic of high grade lesions, and pseudopalisading necrosis is characteristic of GBM.
Rosenthal fibers are characteristic of juvenile pilocytic astrocytomas.
References:
Reference (1)
Limaiem F, Bellil S, Chelly I, et al. Extraventricular neurocytoma in a child mimicking
oligodrendroglioma: a diagnostic pitfall. Pathologica. 2009 Apr;101(2):105-7.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19886559/
Reference (2)
Klysik M, Gavito J, Boman D, et al. Intraoperative imprint cytology of central neurocytoma: The
great oligodendroglioma mimicker. Diagn Cytopathol. 2010 Mar;38(3):202-7
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/19795492/

Question 61

A 13-year-old boy has nocturnal neck pain resulting from the lesion shown in the CT scan. Which
of the following is the most appropriate initial intervention?
Answers:
A. Salicylates and non-steroidal anti-inflammatory analgesics
B. Radiation therapy
C. Cervical brace
D. Surgical resection
E. Biopsy

Answer 61

Salicylates and non-steroidal anti-inflammatory analgesics

Discussion:
Osteoid osteomas typically present with pain and are responsive to salicylates and non-steroidal
anti-inflammatory medications. In the absence of a large lesion that raises the suspicion for
osteoblastoma, deformity, or other concerning features on presentation, medical management of
the pain is the best option. Osteoid osteomas typically presents between 10-20 years of age. The
spine is involved in 10% of cases. CT reveals dense sclerosis around a lytic lesion with a central
calcified nidus of osteoid and woven bone.
References:
Sansur CA, Pouratian N, Dumont AS, Schiff D, Shaffrey CI, Shaffrey ME. Part II: spinal-cord
neoplasms–primary tumours of the bony spine and adjacent soft tissues. Lancet Oncol. 2007
Feb;8(2):137-47. doi: 10.1016/S1470-2045(07)70033-5. PMID: 17267328.

Question 62

Which of the following is the mechanism of action of the oral anticoagulant dabigatran?
Answers:
A. P2Y12 receptor antagonism
B. Cyclooxygenase 1 inhibitor
C. Direct thrombin inhibition
D. Phosphodiesterase inhibition
E. Glycoprotein IIb/IIIa inhibitors

Answer 62

Direct thrombin inhibition

Discussion:
Dabigatran is an oral anticoagulant that exerts it’s effect by direct thrombin inhibition. It is clinically
indicated to reduce the risk of stroke in patients with non-valvular atrial fibrillation, for the treatment
of deep venous thrombosis (DVT) and pulmonary embolism (PE), to reduce the risk of recurrent
DVT and PE for patients who have been previously treated, and for DVT and PE prophylaxis in
patients who have undergone hip replacement surgery. Idarucizumab is used to reverse the
anticoagulant effect of dabigatran. Cilostazol is a phosphodiesterase inhibitor that is used for the
treatment of vascular claudication. Aspirin exerts an antiplatelet effect by inhibiting the enzyme
cyclooxygenase 1. Clopidogrel, ticagrelor, prasugrel, and cangrelor exert antiplatelet effects via
P2Y12 receptor antagonism. Abciximab, eptifibatide, and tirofiban exert prevent platelet
aggregation via glycoprotein IIb/IIIa inhibition.
References:
Reference (1)
Click or tap here to enter text.Boerrhinger Ingelheim Pharmaceuticals. Pradaxa package insert.
2014. Available at: http://bidocs.boehringer-ingelheim.com/BIWebAccess
/ViewServlet.ser?docBase=renetnt&folderPath=/Prescribing%20Information/PIs/Pradaxa
/Pradaxa.pdf.
Pubmed Web link
https://docs.boehringer-ingelheim.com/Prescribing%20Information/PIs/Pradaxa/Pradaxa.pdf
Reference (2)
Kim KS, Fraser JF, Grupke S, Cook AM. Management of antiplatelet therapy in patients
undergoing neuroendovascular procedures. J Neurosurg. 2018 Oct;129(4):890-905. doi:
10.3171/2017.5.JNS162307. Epub 2017 Dec 1. PMID: 29192856.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/29192856/

Question 63

Usually arises in the cerebellopontine angle
Answers:
A. Hemangioblastoma
B. Vestibular schwannoma
C. N/A
D. Astrocytoma
E. Oligodendroglioma

Answer 63

Vestibular schwannoma

Discussion:
Vestibular schwannoma accounts for 75 to 85% of all cerebellopontine angle (CPA) tumors.
Meningiomas account up to 10 to 15%, and epidermoids make up 7 to 8% of all CPA tumors.
Oligodendrogliomas and astrocytomas are often in the cerebral hemispheres. Hemangioblastomas
are commonly found in the cerebellum or around the 4th ventricle. Metastasis are often seen at the
grey-white junction in the cerebral hemispheres or in the cerebellum.
References:
Samii M, Gerganov VM. Tumors of the cerebellopontine angle. Handb Clin
Neurol. 2012;105:633-9.

Question 64

A 59-year-old man comes for evaluation of hearing loss. Evaluation shows high frequency
sensorineural hearing loss and near normal speech discrimination. An MR scan of the brain shows
a 10-mm uniformly enhanced mass within the internal auditory canal. Which of the following is the
most likely complication of stereotactic radiosurgery for this lesion?
Answers:
A. Swallowing difficulty
B. Diplopia
C. Hearing loss
D. Facial weakness
E. Facial numbness

Answer 64

Hearing loss

Discussion:
The most likely complication after vestibular schwannoma radiosurgery is hearing loss. As a less
invasive alternative to surgical resection, stereotactic radiosurgery has been utilized increasingly
over the past 20 years for patients with vestibular schwannomas. Preservation of useful hearing
(speech discrimination scores greater than 50% and a pure tone average less than 50 dB) is
possible in approximately 60 percent of patients after radiosurgery. Facial weakness or numbness
occurs in less than four percent of patients. Diplopia or swallowing difficulty is rare. In large
radiosurgery series, the need for later tumor resection has been less than five percent.
References:
1. Flickinger JC, Kondziolka D, Naranjan A, et al. Acoustic neuroma radiosurgery with marginal
tumor doses of 12 to 13 Gy. International J Radiation Oncology Biol Phys. 2004; 60:225-230.
2. Regis J, Pellet W, Delsanti C, et al. Functional outcome after gamma knife surgery or
microsurgery for vestibular Schwannomas. J Neurosurgery 2002; 97:1091-1100.

Question 65

Which of the following tumors is the most common cause of spinal cord compression in children?
Answers:
A. Wilm’s tumor
B. Osteogenic sarcoma
C. Neuroblastoma
D. Astrocytoma
E. Neurofibroma

Answer 65

Neuroblastoma

Discussion:
Ewing’s sarcoma and neuroblastoma are the most common causes of pediatric epidural spinal
cord compression followed by other tumor histologies such s osteogenic sarcoma, Hodgkin’s
lymphoma, Wlm’s tumor, and rhabdomyosarcoma.
References:
Look AT, Hayes FA, Shuster JJ, et al. Clinical relevance of tumor cell ploidy and N-myc gene
amplification in childhood neuroblastoma: a Pediatric Oncology Group study. J Clin Oncol. 1991
Apr;9(4):581-591.

Question 66

A 56-year-old woman with known breast carcinoma has increased pain after undergoing
stereotactic radiosurgery for a blastic metastatic lesion in the vertebral body of T5. There is normal
thoracic spinal alignment without vertebral body collapse, but the tumor involves the entire
vertebral body. Which of the following factors increases this patient’s risk for a pathologic fracture?
Answers:
A. Limited patient mobility
B. Tumor involvement of the pleura anterior to the vertebral body
C. Endplate erosion at an adjacent level
D. Mechanical back pain
E. Disruption of the anterior longitudinal ligament

Answer 66

Mechanical back pain

Discussion:
While multiple scoring systems have been devised for the rapid assessment of spine instability in
oncological disease, the Spinal Instability Neoplastic Score (SINS) has been widely used and well-
validated (Fisher CG. Spine 2010;35:E1221-E1229). Points are given for location segments of
disease (3-junctional, 2-mobile, 1-semirigid, 0-rigid), presence of mechanical pain (3-yes, 2-no,
1-pain free lesion), bone quality (2-lytic, 1-mixed, 0-blastic), radiographic spinal alignment (4-
subluxation/translation, 2-deformity, 0-normal), vertebral body collapse (3->50% collapse, 2-<50%
collapse, 1-no collapse with >50% body involved, 0-none), and posterolateral involvement (3-
bilateral, 1-unilateral, 0-none). Scores of 1-6 suggest stability, 7-12 suggest potential instability,
and 13-18 suggest instability. The decision and strategy for surgical treatment is complex requiring
the use of interdisciplinary teams as well as understanding of radiobiology and biomechanical
stabilization. The NOMS framework approach has been a recent methodology to determine
surgical treatment in oncology patients (Laufer I. Oncologist 2013;18(6):744-751).
References:
1. Fisher CG, DiPaola CP, Ryken TC, et al. A novel classification system for spinal instability in
neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology
Study Group. Spine (Phila Pa 1976). 2010 Oct 15;35(22):E1221-9.2. Fourney DR, Frangou EM,
Ryken TC, et al. Spinal instability neoplastic score: an analysis of reliability and validity from the
spine oncology study group. J Clin Oncol. 2011 Aug 1;29(22):3072-7.3. Rose PS, Laufer I, Boland
PJ, et al. Risk of fracture after single fraction image-guided intensity-modulated radiation therapy
to spinal metastases. J Clin Oncol. 2009 Oct 20;27(30):5075-9.

Question 67

Which of the following radiosurgical doses is most likely to provide tumor control and hearing
maintenance in a patient with a 1-cm vestibular schwannoma?
Answers:
A. 16-17 Gy
B. 12-13 Gy
C. 18-19 Gy
D. 10-11 Gy
E. 14-15

Answer 67

12-13 Gy

Discussion:
At a dose of 12-13 Gy, the facial nerve function is reportedly very well preserved. Studies
evaluating higher doses have found 8% facial dysfunction at a mean marginal dose of 13.4 Gy
(Rowe et.al.), 16% at 14 Gy (Matthieu et.al.), 33% at 17 Gy (Rowe et.al.) and 50% at 15-16 Gy
(Mallory et al. only evaluating 78% of all patients). Doses lower than 12-13 Gy have been
associated with less effective tumor control.
References:
Phi JH, Kim DG, Chung HT, Lee J, Paek SH, Jung HW. Cancer. 2009 Jan 15; 115(2):390-8.
Flickinger JC, Kondziolka D, Niranjan A, Maitz A, Voynov G, Lunsford LD. Acoustic neuroma
radiosurgery with marginal tumor doses of 12 to 13 Gy. Int J Radiat Oncol Biol Phys. 2004 Sep
1;60(1):225-30. doi: 10.1016/j.ijrobp.2004.02.019. PMID: 15337560