Ch. 7 - Benign brain tumors

Question 1

Most common benign brain tumor

Answer 1

Meningioma (15% of all intracranial tumors, peak incidence in middle age, women > men)

Question 2

Etiology of meningioma

Answer 2

Head trauma, irradiation, NF-2 (esp. multiple meningiomas), female gender is risk factor (hormonal?)

Question 3

Most common meningioma locations

Answer 3

Parasagittal region (superior sagittal sinus or falx) > posterior fossa convexity > sphenoidal wing

Question 4

If multiple meningioma are present, what is the most likely etiology?

Answer 4

NF-2

Question 5

What is the meningioma classification system based on?

Answer 5

Position of origin, NOT histology

Question 6

Psammoma bodies

Answer 6

Whorls of cells which may undergo hyaline degeneration with subsequent deposition of calcium salts; seen in transient type meningiomas

Question 7

Clinical presentation of meningioma

Answer 7

Raised ICP, focal neurological signs, epilepsy

Question 8

Meningiomas are typically fed by what artery?

Answer 8

External carotid artery

Question 9

Preoperative tx of meningiomas

Answer 9

High-dose steroids for severe cerebral edema

Question 10

What characterizes BENIGN brain tumors?

Answer 10

Do NOT invade underlying parenchyma

Question 11

Classic feature of meningioma on plain radiograph

Answer 11

Hyperostosis of cranial vault

Question 12

Tx of meningiomas

Answer 12

Total surgical excision, including obliteration of dural attachment

Question 13

Meningioma recurrence after surgery

Answer 13

Rare if completely excised; most common source of recurrence is from tumor that invaded venous sinus which was not resected

Question 14

Identify the lesion

Answer 14

Typical vault meningioma

Question 15

Why is the term ‘acoustic schwannoma’ a misnomer?

Answer 15

Arises from vestibular component of CN8; should be called vestibular schwannoma

Question 16

Presenting features of acoustic schwannoma

Answer 16

Tinnitus and unilateral partial or complete sensorineural hearing loss

Question 17

What happens during Hallpike caloric testing (irrigate ear canal with cold water) in patient with acoustic schwannoma?

Answer 17

Nystagmus is depressed or absent on side of tumor

Question 18

Surgical options for cerebellopontine approach in resection of acoustic schwannoma

Answer 18

Excision of labyrinth OR

Posterior fossa craniectomy OR

Middle cranial fossa approach

Question 19

Complications of acoustic schwannoma excision

Answer 19

Hearing loss (esp. with translabyrinthine approach), facial paralysis if CN7 damaged, sensory abnormalities if CN5 damaged

Question 20

Identify the lesion

Answer 20

Acoustic schwannoma at cerebellopontine angle

Question 21

Identify the lesion

Answer 21

Bilateral acoustic schwannomas in NF-2

Question 22

What genetic syndrome is associated with intracranial hemangioblastomas?

Answer 22

Von Hipple-Lindau’s disease, though most patients with these tumors do not have the syndrome

Question 23

Unique presenting feature of intracranial hemangioblastoma

Answer 23

Polycythemia 2/2 increased circulating erythropoietin

Question 24

Typical location of intracranial hemangioblastoma

Answer 24

Cerebellum

Question 25

Describe the location and features of colloid cysts

Answer 25

Cyst containing gelatinous material, situated in anterior part of 3rd ventricle; causes obstruction of foramina of Monro leading to hydrocephalus

Question 26

Identify the lesion

Answer 26

Colloid cyst of 3rd ventricle

Question 27

What are epidermoid and dermoid cysts? Where are they most commonly found intracranially? How do they appear histologically?

Answer 27

Epithelial cells embryologically displaced; found principally in arachnoid spaces, cisterns, or skull

Epidermoid cyst - desquamated epithelium with keratin-producing epithelium

Dermoid cyst - includes dermal elements (e.g. hair follicles, sebaceous glands)

Question 28

What layer of the meninges do meningiomas arise from?

Answer 28

Arachnoid layer (arachnoid villi and granulations)