Pathology of Brain Tumors

Question 1

Two main age groups that get CNS tumors?

How do they differ in terms of location?

Answer 1

Kids: first two decades of life –> infratentorial

Older adults: 60s and 70s –> supratentorial

Question 2

Features of grade II tumor?

Answer 2

Increased cellularity

Nuclear atypia

Question 3

Features of grade III tumor?

Answer 3

Anaplastic tumor
Increase cellularity
Nuclear atypia
MITOSES

Question 4

Histological features of glioblastoma multiforme (infiltrative/diffuse astrocytoma)?

Answer 4

Grade IV - all features of grade III + following:

Pseudopalisading necrosis - central necrosis with “stacked” cells on the edge

Vascular/endothelial proliferation

Question 5

Gross and histological features of pilocytic astrocytoma (non-infiltrate/circumscribed astrocytoma)?

Answer 5

Cystic nodule with mural nodule.

Biphasic appearance with compact and loose “piloid” processes.

Rosenthal fibers - eosinophilic EXTRACELLULAR non-cytoplasmic inclusions.

Question 6

Oligodendroglial tumors - what are the molecular markers necessary?

Prognosis relative to GBM?

Histological feature?

Answer 6

Deletion of chromosomes 1p/19q

Better prognosis–more chemosensitive!

Fried-egg appearance with ONLY oligodendrogliomas.

Oligoastrocytomas have BOTH fried eggs and astrocytoma components.

Question 7

Where do ependymomas usually localize?

Prognosis?

Answer 7

To posterior possa, usually in children.

Prognosis based on:

• Location: supratentorial worse location because blocks drainage
• Age: young than 3 cannot undergo radiation

Question 8

Histological features of ependymomas?

Answer 8

Perivascular pseudorosettes

Question 9

Myxopapillary ependymoma

Answer 9

The ONLY GRACE I EPENDYMOMA.

Localizes UNIQUELY to conus/cauda equina/filum terminale

Question 10

Etiology of medulloblastoma? Localization?

Clinical progression and histology?

Answer 10

Neuroectoderm
Localized to cerebellum, usually vermis

Can enter 4th ventricle to cauda equina termed “drop metastasis”

Would see small round blue cells and homer wright reosettes

Question 11

Meningioma

Commonly affected population?
Histology?
Imaging?

Answer 11

Older women - most common BENIGN CNS tumor in adults

If affect younger, often associated with NF2

Whorled cells that can calcify and turn int psammoma bodies

Imaging: bony hyperostosis that overlies dura with “dural tail”

Question 12

Craniopharyngioma

Commonly affected population?
Location?
Imaging?
Histology?

Answer 12

Children/first two decades of life

Location: suprasellar region –> can compress optic chiasm to cause bilateral hemianopsia

Imaging: cystic component with calcifications/cholesterol crystals

Histology: cystic spaces, calcifications, “wet” keratin (keratin without nuclei)

Question 13

Schwannoma

Location
Histological finding

Answer 13

Cerebellopontine angle –> bilateral acoustic schwannomas –> auditory symptoms

Verocay bodies - acellular area with palisading cells

Question 14

NF2

Genetics
Associated tumors

Answer 14

Autosomal dominant, Merlin gene on chromosome 22

• Bilateral acoustic schwannomas at cerebellopontine angle
• Multiple meningiomas
• Ependymomas (spinal)