CNS Tumors

Question 1

Are CNS tumors more often metastatic or primary?

Answer 1

50% metastatic (from LUNG, BREAST, KIDNEY)

50% primary

Question 2

Children primary tumors are most often ___?

Adult primary tumors are most often __? Supratentorial or Infratentorial?

Answer 2

CHILDREN: INFRATENTORIAL
ADULT: SUPRATENTORIAL
Children are shorter and so they’ll be infratentorial

Question 3

CHILDREN: What is the most common PRIMARY CNS tumor What is the most common BENIGN PRIMARY CNS tumor? What are the two possible MALIGNANT PRIMARY CNS tumors?

Answer 3

1. MOST COMMON = PILOCYTIC ASTROCYTOMA (benign tumor of astrocytes)
2. MEDULLOBLASTOMA = Malignant tumor of granular cells of cerebellum (Neuroectoderm)
3. EPENDYMOMA = Malignant tumor of ependymal cells

Question 4

ADULT: What is the most common PRIMARY CNS tumor? What primary tumors are most common in adults? (1 malignant, 1 benign)

Answer 4

MOST COMMON = GLIOBLASTOMA MULTIFORME = MALIGNANT CNS TUMOR of ASTROCYTES

MENINGIOMA = Benign tumor of arachnoid cells in FEMALES
OLIGODENDROGLIOMA = Malignant tumor of oligodendrocytes

Question 5

MNEMONIC for children and adult PRIMARY CNS TUMORS (MALIGNANT)

Answer 5

Children (immature) say ME ME! I want it - MEDULLOBLASTOMA + EPENDYMOMA
Adult (mature) know what they don’t want say GO (away cns tumor)! - GLIOBLASTOMA MULTIFORME + OLIGODENDROGLIOMA

Question 6

What is the classic morphological change on BIOPSY of a GLIOBLASTOMA MULTIFORME (Adult malignant tumor of glial cell - astrocytes)?

Answer 6

BUTTERFLY LESION - Initially arises from the CEREBRAL HEMISPHERE -> Crosses the corpus luteum

Question 7

What are the 2 histological changes of a GLIOBLASTOMA MULTIFORME?
What is the diagnostic test marker of this CNS tumor?

Answer 7

1. PSUEDOPALISADING NECROSIS - Tumor cells lining around areas of necrosis [“BLAST off in a palisading manner”]
2. ENDOTHELIAL MICROVASCULAR PROLIFERATION

GFAP+ = Marker = Intermediate filament of GLIAL CELLS

Question 8

What is a MENINGIOMA? Who is the typical pt affected? What is the marker of a MENINGIOMA?

Answer 8

BENIGN tumor of ARACHNOID CELLS - Express estrogen receptor***
Typical pt = WOMEN ADULTS

Question 9

What is the most common Sx of a MENINGIOMA?

Answer 9

SEIZURE

Tumor is attached to the dura -> Compresses the cortex but does NOT invade the cortex -> SEIZURES

Question 10

What are two histological evidences of a MENINGIOMA?

Answer 10

“MEN (meningioma) and FEMALES (typical pt affected) like to WHORL around and CALCIFY together”

1. WHORLED - spindled cells arranged in a whorled pattern
2. PSAMMOMA BODIES - calcifications of the spindled cells

Question 11

What is seen on imaging of a MENINGIOMA?

Answer 11

DURAL TAIL

Question 12

What is a BENIGN TUMOR of SCHWANN CELLS (cells that myelinate PNS)? What is the most common nerve affected?

Answer 12

SCHWANNOMA - Can affect BOTH CRANIAL + SPINAL NERVES

CN VIII = most common nerve compressed by tumor as it exits at the CERBELLOPONTINE ANGLE

Question 13

How does a SCHWANNOMA most commonly present clinically?

Answer 13

Most commonly involves CN VIII - TINNITUS, LOSS OF HEARING

Question 14

What is the diagnostic marker of a SCHWANNOMA? What other pathologies also show this marker?

Answer 14

S100+

Also seen in LANGERHANS CELL HISTIOCYTOSIS + MELANOMA

Question 15

What is associated with BILATERAL SCHWANNOMAS?

Answer 15

NEUROFIBROMATOSIS TYPE 2

Almost 100% of Schwannomas have bi-allelic inactivation of NF-Type II

Question 16

What are 2 histologic features of SCHWANNOMAS?

Answer 16

1. SPINDLE SHAPED CELLS with rod-like nuclei (S = spindle= schwannomas)
2. VEROCAY BODIES = ALTERNATING hyocellular areas (antoni B) and hypercellular areas (antoni A)

Question 17

What is the second most common MALIGNANT tumor in adults?

Answer 17

OLIGODENDROLGIOMA - Malignant tumor of oligodendrocytes (GO)

Question 18

Where does an OLIGODENDROGLIOMA most commonly present in an adult? Thus, what sx is most likely?

Answer 18

MALIGNANT TUMOR OF oligodendrocytes = CALCIFIED tumor in WHITE MATTER of FRONTAL LOBE
Usually presents with SEIZURES**

Question 19

What are the two histological features of an adult OLIGODENDROGLIOMA?

Answer 19

O = SHAPE OF AN EGG! Eggs come from a CHICKEN

1. FRIED EGG APPEARANCE - Round nuclei with clear appearance
2. CHICKEN WIRE CAPILLARY pattern - Nuclei are NOT lined up together

Question 20

What is a PILOCYTIC ASTROCYTOMA? Who is the typical pt? What is the most commonly involved structure?

Answer 20

MOST COMMON, BENIGN TUMOR of ASTROCYTES in the CEREBELLUM - Children pt
(cerebellum since most CNS Tumors are INFRATENTORIAL)

Question 21

What is seen on imaging of a PILOCYTIC ASTROCYTOMA?

Answer 21

PILOCYTIC, piloCYSTic

CYST with mural thrombus in the cerebellum

Question 22

What are 2 histological evidences of a PILOCYTIC ASTROCYTOMA?

Answer 22

1. Elongated cells (eosinophilic granular bodies) with PILOID, hair like FIBERS
   Think PILO, LILLY, ROSE! - flowers
2. ROSENTHAL, eosinophilic corkscrew FIBERS coming off of tumor cells

Question 23

What is the diagnostic marker of a PILOCYTIC ASTROCYTOMA?

Answer 23

PILOCYTIC ASTROCYTOMA = Tumor of astrocytes** of cerebellum = glial cell

GFAP+ = IMF of glial cells

Question 24

What is a MEDULLOBLASTOMA? Who is the typical pt? What is most commonly affected?

Answer 24

MALIGNANT TUMOR of NEUROECTODERMAL cells of the CEREBELLUM (infratentorium) of CHILDREN
“ME”

Question 25

ROSETTE FIBERS HOMER WRIGHT ROSETTES PERIVASCULAR ROSETTES

Answer 25

ALL CHILDREN PRIMARY CNS TUMORS have "roses" (Children like to pick up roses from the garden) 1. Rosette fibers = Elongated fibers of a PILOCYTIC ASTROCYTOMA (Benign since it's not "ME") 2. Homer wright rosettes = Blue cells surrounding neuritic processes of a MEDULLOBLASTOMA (Malignant) 3. Perivascular rosettes = Ependymomas extend their processes AWAY from BV = Clearing from the BV= EPENDYMOMA

Question 26

What are 2 histological evidences of a MEDULLOBLASTOMA?

Answer 26

1. MedulloBLastoma = BLue cells (small round, neoplastic blue cells) 2. HOMER-WRIGHT ROSETTES = Blue cells surrounding pink neuritic processes

Question 27

Why does a MEDULLOBLASTOMA have a poor prognosis? Think in terms of metastasis.

Answer 27

Medulloblastoma can grow RAPIDLY into the 4th ventricle -> Spread into the CSF -> Spinal cord -> Metastasis to the cauda equina that extends into S2 = DROP METASTATIS

Question 28

What is DROP METASTASIS in relation to children primary CNS tumors?

Answer 28

MEDULLOBLASTOMA that arises in cerebellum -> Extends into 4th ventricle -> CSF -> spinal cord -> cauda equina

Question 29

What is an EPENDYMOMA? Who is the typical pt? Where does it most commonly affect?

Answer 29

``` EPENDYMOMA = Malignant (ME) CNS tumor of EPENDYMAL CELLS (lining ventricles) in a CHILD 4th ventricle (INFRATENTORIAL) = most commonly involved ```

Question 30

How does a child with EPENDYMOMA clinically present? What is the histological finding?

Answer 30

HYDROCEPHALUS: Due to tumor of ependymal cells lining 4th ventricle and extending into that space PERIVASCULAR ROSETTES: Ependymal neuritic processes extended AWAY from BV = clearing from the BV

Question 31

Ddx of a BITEMPORAL HEMIANOPSIA in a child:

Answer 31

PITUITARY ADENOMA | CRANIOPHARYNGIOMA

Question 32

What is a CRANIOPHARYNGIOMA? Who is the typical pt? Where does it typically affect?

Answer 32

CRANIOPHARYNGIOMA = BENIGN Tumor arising from EPITHELIAL REMNANTS OF RATHKE POUCH = SUPRATENTORIAL MASS in CHILD or YOUNG ADULT Normally: Rathke pouch loses connection with the upper protrusion of the pharynx (floor of the mouth) to form the ANTERIOR PITUITARY and sits on the sella turcica

Question 33

How does a CRANIOPHARYNGIOMA result in BITEMPORAL HEMIANOPSIA?

Answer 33

CRANIOPHARYNGIOMA - tumor of epithelial remnants of rathek pouch on sella turcica -> Can compress on the OPTIC CHIASM -> Bitemporal hemianopsia

Question 34

What is the classic imaging seen of a CRANIOPHARYNGIOMA?

Answer 34

Craniopharygioma - See CALCIFICATIONS, derived from "tooth-like" tissue

Question 35

Is a CRANIOPHARYNGIOMA typically malignant or benign? Can it be treated by resection

Answer 35

BENIGN but tends to recur after resection

Question 36

CALCIFICATIONS: WHORLED BODIES/PSAMMOMA CALCIFICATIONS: CALCIFICATIONS of a SUPRATENTORIAL MASS

Answer 36

PSAMMOMA BODIES: Meningioma (malignant) | Calcifications of supratentorial mass: Craniopharyngioma (benign)

Question 37

ROSENTHAL FIBERS | EOSINOPHILIC GRANULAR FIBERS

Answer 37

PILOCYTIC ASTROCYSTOMA

Question 38

PERIVASCULAR ROSETTES

Answer 38

EPENDYMOMA

Question 39

HOMER-WRIGHT ROSETTES + SMALL BLUE CELLS

Answer 39

MEDULLOBLASTOMA

Question 40

BUTTERFLY LESION (Crossing over corpus callosum) + PSEUDOPALISADING

Answer 40

GLIOBLASTOMA MULTIFORME

Question 41

FRIED EGG APPEARANCE + CHICKEN-WIRE CAPILLARY PATTERN

Answer 41

OLIGODENDROGLIOMA (malignant adult)

Question 42

GFAP+

Answer 42

IMF of GLIAL CELLS (astrocytes) = CHILDREN PILOCYTIC ASTROCYTOMA + GLIOBLASTOMA MULTIFORME (ADULTS)

Question 43

CYSTIC LESION WITH MURAL THROMBUS on imaging

Answer 43

PILOCYTIC ASTROCYTOMA (Child, benign tumor)

Question 44

DROP METASTASIS to CAUDA EQUINA

Answer 44

MEDULLOBLASTOMA

Question 45

NEUROFIBROMATOSIS TYPE 2 BI-ALLELIC GENE INACTIVATION is associated with which CNS tumor?

Answer 45

SCHWANNOMA - TUMOR OF SCHWANN CELLS (most typically CN VIII), S100+

Question 46

Calcified tumor of white matter in FRONTAL LOBE

Answer 46

FRONTAL LOBE - think supratentorial adults | frOntal lObe = 2O's = OLIGODENDROGLIOMA

Question 47

VEROCAY BODIES (ANTONI A [HYPERCELLULAR] + ANTONI B [HYPOCELLULAR])

Answer 47

Verocay bodies - alternating patterns think MUSIC = Need to hear = CN VIII SCHWANNOMA (benign tumor of schwanna cells)