Brain Tumors

Question 1

What is the most common benign brain tumor in adults?

Answer 1

Meningioma is the most common primary brain tumor overall in adults, accounting for about 30-35% of primary brain tumors.

90% are benign.

Question 2

What is this lesion?

Answer 2

A meningioma.

These are typically benign, slow-growing extra-axial tumor arising from the meningothelial cells of the arachnoid. It is the most common primary brain tumor in adults.

Question 3

What is the typical demographic affected by meningiomas?

Answer 3

Meningiomas are more common in women, especially between the ages of 40-70 years, due to their association with hormonal factors (e.g., estrogen/progesterone receptor expression).

Question 4

What are the common imaging features of a meningioma?

Answer 4

Extra-axial (external to brain parenchyma) and may have a dural attachment.

Dural-based mass with a homogenous enhancement.

Dural tail sign (thickening of the dura adjacent to the tumor).

Well-circumscribed, often compressing adjacent brain tissue.

Hyperdense on CT and highly vascular on imaging.

Increase in bone density due to infiltration of the overlying bone.

Question 5

What is a common histopathologic finding in meningiomas?

Answer 5

Spindle cells concentrically arranged in a whorled pattern.

Psammoma bodies.

Question 6

What are some important immunohistolochemical stains seen with meningiomas?

Answer 6

Vimentin (mesenchymal tissue marker).

S-100.

CD68 (histocytes).

Question 7

Meningiomas are derived from what type of cell?

Answer 7

Arachnoid cell origin.

Question 8

What are the typical clinical features of a meningioma?

Answer 8

Progressive headaches.

Focal neurological deficits (e.g., weakness, sensory changes).

Seizures (due to cortical irritation).

Symptoms of increased ICP: Nausea/vomiting, vision changes, personality changes.

Question 9

What factors increase the risk of meningioma development?

Answer 9

Female gender (due to hormonal influence) in a 3:1 distribution.

Prior radiation exposure to the head.

Neurofibromatosis type 2 (NF2) - chromosome 22.

Neurofibromatosis type 1 (NF1) - chromosome 17.

MEN1 association.

Question 10

How are meningiomas classified pathologically?

Answer 10

Grade I: Benign (most common).

Grade II: Atypical, more aggressive.

Grade III: Malignant, rare and highly aggressive.

Question 11

Where do meningiomas tend to develop?

Answer 11

Parasagittal (20.8 %)

convexity (15%)

tuberculum sellae (13%)

sphenodial ridge (12%)

olfactory groove (10%)

falx cerebri (8%)

lateral ventricle (4%)

tentorium cerebelli (4%)

orbital (1%)

Spinal (1%)

Question 12

A significant portion of meningioma can appear in what part of the body other than within the brain?

Answer 12

Along the spinal cord.

According to a 336 case series, the occurrence of spinal meningioma was ~1%.

Question 13

How is a meningioma diagnosed?

Answer 13

Imaging: MRI with contrast to identify a dural-based mass and dural tail.

Biopsy: Needed only if imaging is inconclusive

Question 14

How does meningiomas appear on the T1WI vs T2WI?

Answer 14

T1WI : isointense

T2WI : hypointense

Question 15

What are the management options for meningiomas?

Answer 15

Observation: Small, asymptomatic tumors.

Surgical resection: First-line for symptomatic or growing tumors.

Radiation therapy: For incompletely resected or recurrent tumors.

Question 16

In terms of management, at what size are meningiomas observed?

Answer 16

Less than 3 cm meningiomas are observed with repeat imaging every 3 to 6 months.

Question 17

When is neurosurgery (or radiation) necessary for a meningioma?

Answer 17

When more than 3 cm and symptomatic.

perform surgery +/- radiation.

Question 18

What complications can arise from untreated meningiomas?

Answer 18

Mass effect: Progressive neurological deficits, seizures, cerebral edema, obstructive hydrocephalus.

Increased intracranial pressure: Headache, vomiting, vision changes, personality changes.

Signs of malignancy: DVTs.

Risk of malignant transformation (rare).

Question 19

What is the prognosis for patients with meningiomas?

Answer 19

Most meningiomas are benign and have an excellent prognosis following surgical resection. Atypical and malignant meningiomas may recur and require additional treatment.