CNS Tumors

Question 1

Where are most CNS tumors found?

Answer 1

Over 85% are seen within the brain

Question 2

Where are most CNS tumors found in adults?

Answer 2

Supratentorial - typically in the cerebrum

Question 3

Where are most CNS tumors found in children?

Answer 3

Infratentorial - typically in the cerebellum

Question 4

What is unique about benign and malignant CNS tumors?

Answer 4

Even benign tumors can have fatal outcomes due to their location and often surgical resection is restricted due to anatomical constraints that could leave to damage and loss of function.

Question 5

Expansile Growth

Answer 5

Sharp border between the tumor and surrounding tissue

Question 6

Infiltrative Growth

Answer 6

Single tumor cells spread in brain parenchyma and surround normal structures

Question 7

How frequent is the metastasis of CNS tumors?

Answer 7

VERY rare.

Question 8

What are some common signs of CNS tumors?

Answer 8

• Headaches
• Nausea and vomiting
• Seizures
• Syncope

Question 9

What is the most common CNS tumor in adults?

Answer 9

Glioblastoma Multiforme

Question 10

What is the most common CNS tumor in children?

Answer 10

Pilocytic Astrocytoma

Question 11

What are the types of gliomas?

Answer 11

• Astrocytoma
• Oligodendroglioma
• Ependymoma

Question 12

What is seen on microscopy of pilocytic astrocytoma?

Answer 12

Piloid Cells with hair-like processes - biphasic architecture with compact and microcystic areas

Question 13

What kind of fibers will be seen in pilocytic astrocytoma?

Answer 13

Rosenthal Fibers

Question 14

Glioblastoma Multiforme

Answer 14

Malignant astrocytoma and is the most common CNS tumor in adults. It can cross the corpus callosum as a butterfly lesion and shows with areas of necrosis

Question 15

What are the cellular features of glioblastoma multiforme?

Answer 15

• Pseudopalisading cells around necrosis
• Endothelial cell hyperplasia
• GFAP positive

Question 16

Oligodendroglioma

Answer 16

Malignant tumor of oligodendrocytes that has a better prognosis that others and may present with seizures.

Question 17

What is a classic finding of oligodendrogliomas on CT?

Answer 17

Intratumoral Calcifications

Question 18

What is the appearance of oligodendroglioma on histology?

Answer 18

Fried egg appearance of cells with chicken-wire capillary pattern and possible perineuronal/vascular satellitosis.

Question 19

What are the rosettes seen in medulloblastoma?

Answer 19

Homer-Wright Rosettes - central core of delicate neutrophil fibrils

Question 20

What are the rosettes seen in retinoblastoma?

Answer 20

Flexner-Wintersteiner Rosettes - cells are arranged around an empty lumen

Question 21

What are the rosettes seen in ependymoma?

Answer 21

Perivascular Pseudorosette - halo of tumor cells surrounds a blood vessel

AND

True Ependymal Rosette - halo of tumor cells surrounds an empty central lumen

Question 22

Ependymoma

Answer 22

Arises in the walls of ventricles and central canal of spinal cord and is more frequent in children with the 4th ventricle as the most common site.

Question 23

Medulloblastoma

Answer 23

Arises from undifferentiated neuroectodermal cells and is malignant and found in children.

Question 24

What is seen on histology of medulloblastoma?

Answer 24

Sheets of undifferentiated cells with scanty cytoplasm and dark staining nuclei

Question 25

Meningioma

Answer 25

Arises from arachnoid cells and is benign and seen in adult females and often asymptomatic but can cause seizures.

Question 26

What are some of the histologic features of meningioma?

Answer 26

- Psammoma bodies - Whorls - Fascicles in the fibroblastic variant

Question 27

Craniopharyngioma

Answer 27

Benign tumor in children that is derived from Rathke's pouch and can cause visual symptoms and endocrine dysfunction.

Question 28

What can craniopharyngioma be confused for?

Answer 28

Pituitary Adenoma

Question 29

What is a symptom in children that raises the possibility of craniopharyngioma?

Answer 29

Presentation of bitemporal hemianopsia

Question 30

What are some features of craniopharyngioma that can be seen on CT?

Answer 30

Calcifications of the tumor are common

Question 31

Schwannoma

Answer 31

Benign tumor of Schwann cell origin that is common at the CPA and CN VIII as an acoustic neuroma leading to hearing loss and tinnitus

Question 32

What does bilateral acoustic neuromas raise suspicion for?

Answer 32

Neurofibromatosis Type-2

Question 33

What is a marker for Schwannoma?

Answer 33

S100

Question 34

What are the common sources of metastasis to the CNS?

Answer 34

- Lung - Breast - Kidney

Question 35

A 56‐year‐old man has had headaches and difficulty concentrating for the past 2 months. He then begins to exhibit odd behavior, such as hitting golf‐balls at his neighbors doors and windows. He suffers a grand mal seizure, and is admitted to the hospital. MR imaging of the brain reveals a large mass with extensive necrosis in the left cerebral hemisphere extending across corpus callosum into the right hemisphere. Which of the following neoplasms is he most likely to have? A. Meningioma B. Glioblastoma C. Medulloblastoma D. Metastatic adenocarcinoma

Answer 35

B. Glioblastoma

Question 36

Neurofibromatosis Type-1

Answer 36

Mutation of neurofibromin-GTPase activating protein on Ch17 that leads to a high chance of malignant transformation

Question 37

What are the symptoms of NFT1?

Answer 37

Neurofibromas, acoustic schwannomas, optic nerve gliomas, Lisch nodules and café‐au‐lait spots. – Plexiform neurofibroma is pathognomonic of NF 1

Question 38

Neurofibromatosis Type-2

Answer 38

Mutation of gene on Ch22 that is a tumor suppressor gene, Merlin, leading to bilateral acoustic Schwannomas and multiple meningiomas

Question 39

Tuberous Sclerosis

Answer 39

Hamartomatous lesions from mutations in TSC1 and TSC2 (hamartin and tuberin)

Question 40

What is the triad of tuberous sclerosis?

Answer 40

- Adenoma sebaceum - Seizures - Mental retardation

Question 41

Von Hippel-Landau Disease

Answer 41

VHL tumor suppressor gene on Ch3 is mutated which leads to increased HIF and VEGF leading to growth and tumor formation.

Question 42

What is VHL disease associated with?

Answer 42

- Hemangioblastoma | - Renal cell carcinoma

Question 43

Hemangioblastoma

Answer 43

Closely arranged thin‐walled capillaries with little intervening parenchyma ‐Can produce erythropoietin ‐ secondary polycythemia