CNS Tumors I

Question 1

Grade II brain tumor is…

Answer 1

Benign

Question 2

Grade III brain tumor is…

Answer 2

Anaplastic

Question 3

Grade IV brain tumor is…

Answer 3

Very aggressive

Question 4

Give the epidemiology of Pilocytic Astrocytoma

Answer 4

Most common CNS tumor in children (usually between the ages of 8-13) Grade I 15% of patients with Neurofibromatosis have this 33% of patients have Trisomy 7 and 8

Question 5

Give the morphology of Pilocytic Astrocytoma

Answer 5

Well-circumscribed, homogenous, contrast enhancing, and cyst formation tends to occur Location is infratentorial, around the ventricles (mainly 3rd and 4th) and midline structures. Pathoma says it usually arises in the cerebellum. These cells are GFAP positive.

Question 6

Histology of Pilocytic Astrocytoma

Answer 6

These cells look spindly and hair-like despite being astrocytic in nature Rosenthal fibers (google an image of this!)

Question 7

Diffuse Astrocytoma Epidemiology

Answer 7

Peak age of incidence is 34 yrs old (30’s for astrocytomas, 40’s for glioma’s) Grade II Male: Female ratio: 1.18:1 60% have a p53 mutation ***Old test question p16/p15 mutations also seen

Question 8

Diffuse Astrocytoma Morphology

Answer 8

On neuroimaging: ill-defined and diffuse, homogenous masses, cystic changes and calcifications Location: Cerebral hemispheres (front-temporal lobe), but they can occur anywhere there are astrocytes Gross: ill-defined, no necrosis or hemorrhage, frequently see cystic degenerations

Question 9

Diffuse Astrocytoma Histology

Answer 9

Fibrillary backround (looks like a spider’s web!). Anytime you see this think Astrocytoma GFAP +

Question 10

Gemistocytic Astrocytoma

Answer 10

Gemisto- “full or fat” One variety of the diffuse astrocytoma that is more aggressive Still has fibrillary backround and GFAP+

Question 11

Anaplastic Glioma Epidemiology

Answer 11

Peak incidence: 40s Grade III This is the result of astrocytoma that recurs. Glioma is more aggressive than astrocytoma > 90%: p53 mutation 30% : p16 deletion 25%: Rb alterations 40%- loss of heterozygotic 19q

Question 12

Anaplastic Glioma Morphology

Answer 12

Neuroimaging: Ill-defined mass that is not homogenous like Astros, RING OF ENHANCEMENT. Location: Cerebral hemispheres

Question 13

Anaplastic Glioma Histology

Answer 13

Irregular cells but fibrillary backround is still there so they still mark positive with GFAP. Will see nuclear atypia, increased cellularity, and mitotic activity.

Question 14

Differential Diagnosis for Ring Enhancing Lesions

Answer 14

1) Toxoplasmosis 2) Lymphomas 3) Glioblastomas/ anaplastic gliomas

Question 15

What is the difference between primary and secondary Glioblastoma Multiforme (GBM)?

Answer 15

Primary: No specific p53 mutations. EGFR amplification and overexpression. “When it was born, it was aggressive” Secondary: Begins with p53 mutation. Progresses from low grade astrocytoma to anaplastic astrocytoma to glioblastoma.

Question 16

Epidemiology of Glioblastoma Multiforme

Answer 16

Most aggressive glial brain tumor (1 year survival) Grade IV Peak age: 50s >90% p53 mutation

Question 17

Glioblastoma Multiforme Morphology

Answer 17

Neuroimaging: Irregularly shaped lesions, ring-like enhancement, ill-defined, heterogenous Gross: Extensive necrosis and hemorrhages Location: cerebral hemispheres, contralateral invasion through Corpus Callosum (sometimes called the “Butterfly Glioma”)

Question 18

Glioblastoma Multiforme Histology

Answer 18

Pseudo-palisading, multinucleated cells, mitotic activity, endothelial cell proliferation Still see fibrillary backround, so it will be GFAP +

Question 19

3 Things Used to Diagnose Glioblastoma Multiforme

Answer 19

1) Pleomorphism 2) Necrosis…pseudo-palisading 3) Endothelial cell proliferation…endothelial cells become thick, glomerular-like structures

Question 20

Pontine Glioma

Answer 20

Diffuse expansion of the pons, usually high grade astrocytoma or GBM Grade IV Tumors in the pons tend to be very aggressive Cells are multinucleated due to overzealous mitosis

Question 21

Giant Cell Glioblastoma Epidemiology

Answer 21

Age: 40s Grade IV Location: Cerebral hemispheres 75-90%- p53 mutations 33%- PTEN mutations

Question 22

Giant Cell Glioblastoma Histology

Answer 22

Giant multinucleated cells Pseudo-palisading necrosis Perivascular accumulation of tumor cells (“rosette-like pattern)

Question 23

Gliosarcoma Epidemiology

Answer 23

Mixture of glioblastoma from brain parenchyma and a sarcoma stemming from the meninges Age of onset: 50s Grade IV p53 mutation, loss of chromosomes 10 and 17, Rb alterations

Question 24

Gliosarcoma Morphology

Answer 24

Location: Exclusively in the cerebral hemispheres Gross: Ring-enhancement

Question 25

Gliosarcoma Histology

Answer 25

Areas of glial differentiation Mesenchymal portion: vascular, cartilage, bone, smooth and striate muscle Contains two distinct areas: one part is mainly collagen while the other part is the glioblastoma part

Question 26

Gliomatosis Cerebri Epidemiology

Answer 26

Age: 40-50 yrs old Grade II Karyotype 44, XY

Question 27

Gliomatosis Cerebri Morphology

Answer 27

Eventually substitute the entire brain. This tumor does not form a mass. Neuroimaging: Type1...extensive infiltration of white and grey matter. Type 2: Like type I plus obvious neoplastic mass

Question 28

Gliomatosis Cerebri Histology

Answer 28

Mild astrocytic tumor with elongated glial cells, fibrillary backround with homogenous cells

Question 29

Oligodendroglioma Epidemiology

Answer 29

Age: 40 yrs Grade II 80%- deletions in 19q 67%- loss of heterozygosity in chromosome 1p

Question 30

Oligodendroglioma Morphology

Answer 30

Well-defined soft masses that are usually superficial located in the cortex Gross: reddish areas of hemorrhage

Question 31

Oligodendroglioma Histology

Answer 31

"Fried eggs" with clear halo Delicate vascular pattern..."chicken wire" Calcifications GalC marker positive

Question 32

Central Neurocytoma Epidemiology

Answer 32

Age: 20s Grade II Location: Arise from the septum Histology: Looks identical to oligodendrogliomas with fried egg appearance, but this is a tumor of neurons

Question 33

Medulloblastoma Epidemiology

Answer 33

Very common pediatric CNS tumor Peak incidence: 7-12 yrs old Grade IV 65% of pts are male Location: Infratentorial 50% have 17q mutations

Question 34

Medulloblastoma Morphology

Answer 34

3 Types: 1) Classic: Midline cerebellum, usually the vermis 2) Neuroblastic: Tumor of the vermis and of young children 3) Desmoplastic: Well circumscribed, solid masses. More often on the hemispheres of the cerebellum and a tumor of adolescence (age 12-20)

Question 35

Medulloblastoma Histology

Answer 35

Classic: Densely packed sheets of blue cells, undifferentiated. Markers: Synaptophysin and class 3 beta tubulin Neuroblastic: Rosettes...look like piles of coins Desmoplastic: Most differentiated. Pale islands

Question 36

Ependymoma Epidemiology

Answer 36

Age 5-10 Most common glioma in the spinal cord when found in adults Grade II Location: Most commonly in the 4th ventricle Alterations in 22q

Question 37

Ependymoma Histology

Answer 37

Pseudorosettes and Rosettes

Question 38

Choroid Plexus Tumors Epidemiology

Answer 38

Age: Younger than 20 Choroid Plexus Papilloma: Grade I Choroid Plexus Carcinoma: Grade III Associated with Li-Fraumeni Syndrome- mutation in TP53 codon 248

Question 39

Choroid Plexus Tumor Morphology

Answer 39

Neuroimaging: hyperdense tumors w/in the lateral ventricle, but can also occur in the 4th ventricle Hydrocephalus is the most common abnormality

Question 40

Choroid Plexus Tumor Histology

Answer 40

Papillary tumor: Positive for cytokeratin

Question 41

Craniopharyngioma Epidemiology

Answer 41

Most common non-neuroepithelial intracerebral tumor Derived from Rathke's pouch epithelial cells Age: 5-14 yrs. Common in younger children. Grade I

Question 42

Craniopharyngioma Morphology

Answer 42

Solid masses w/ predominant cyst component

Question 43

Craniopharyngioma Histology

Answer 43

Nodules of compact keratin and calcifications

Question 44

Hemangioblastoma Epidemiology

Answer 44

Age: 20s Associated with von Hippel-Lindau (VHL) Exclusively in lateral cerebellar hemisphere Grade I

Question 45

Hemangioblastoma Morphology

Answer 45

Well-circumscribed nodules within the wall of larger cysts usually seen in the lateral cerebellar hemisphere Yellow (lipid rich), highly vascularized mass

Question 46

Hemangioblastoma Histology

Answer 46

Clear cells with a prominent vascular network Markers: NSE (neuronal specific enolase) and CD31

Question 47

CNS Lymphoma Epidemiology

Answer 47

Peak incidence: 60-70 yrs old. If you have AIDS, 39 years old.

Question 48

CNS Lymphoma Morphology

Answer 48

Single or multiple masses Ring of enhancement Location: Most common location is the basal ganglia Abnormalities in chromosomes 1, 6, 7, and 14

Question 49

CNS Lymphoma Histology

Answer 49

Angiocentric pattern "perivascular cuffing" of lymphocytes B-cell lymphomas (CD 20, CD 79a)

Question 50

Meningioma Epidemiology

Answer 50

Originate in the meninges Age: 60-70 yrs Grade I: most common 22q12 and NF2 gene mutations

Question 51

Meningioma Morphology

Answer 51

Well demarcated masses that originate in the dura. Has a broad dural attachment. Cerebral convexity associated with the falx cerebri

Question 52

Meningioma Histology

Answer 52

Psammoma bodies...pink, round concentric calcifications

Question 53

Schwannoma Epidemiology

Answer 53

Age: 40-60 yrs Involves CN VIII at the Pontocerebellar Angle If a patient has bilateral Schwannomas, they have Neurofibromatosis Grade I Tumor markers: S-100

Question 54

Schwannoma Histology

Answer 54

Spindle-shaped interdigitating cells, Nuclear palisading 2 types of areas: Antoni A...densely packed cells with Verocay bodies Antoni B...loosely packed cells, more myxoid