CNS Tumors Flashcards
Differentiate expansile from infiltrative growth
Expansile growth: sharp border between tumor and surrounding tissue
Infiltrative growth: Single tumor cells percolate through the brain parenchyma and surround normal structures
How often do primary brain tumors metastasize outside of the CNS?
Almost never
What are the three most common primary CNS tumors in adults?
Meningioma, schwannoma, glioblastoma
What are the three most common primary CNS tumors in kids?
pilocytic astrocytoma (benign), ependymoma, medulloblastoma (highly malignant)
What is the most common glioma?
Astrocytoma
Where do astrocytomas appear in the brain?
Anywhere
What age group is affected by astrocytomas?
All age groups
Give an example of a grade I astrocytoma
Pilocytic astrocytoma
What is the prognosis of a pilocytic astrocytoma?
Possibility of cure following surgical resection alone
What is the identifying histologic cellular appearance of pilocytic astrocytomas?
Piloid cells with hair-like processes
What is the identifying architecture of pilocytic astrocytomas?
Biphasic- alternating areas of compact and microcytic areas
What are rosenthal fibers?
Characteristic red blobs found in pilocytic astrocytomas?
What are the cancerous cells in glioblastomas?
Malignant astrocytes
What is the characteristic appearance of glioblastoma on MRI?
Butterfly lesions- crosses the corpus callosum
How do glioblastomas appear on CT?
Ring-enhancing mass
What are the hyperplastic cells found in glioblastoma?
Endothelial cells- they are secreting VEGF and other growth factors.
Glioblastoma tumor cells (astrocytes) are positive for what on IHC?
GFAP
What is the prognosis for glioblastoma?
bad
What is the most common presentation of an oligodendroma?
Frontal lobe mass- may present with seizures
What are characteristic findings of an oligodendroglioma on CT?
intratumoral calcifications on CT
Which tumors shows “fried eggs” cells and “chicken-wire” capillaries on HandE staining?
Oligodendrogliomas
Describe the lumen of a homer-wright rosette (common in Medulloblastomas)
central pore is composed of delicate neuropil fibers
From what cells do ependymomas arise?
Ependyma cells that line the walls of the ventricles and central canal of the spinal cord
What is the most common side of an ependymoma?
4th ventricle –> hydrocephalus
Where in the CNS do ependymomas typically arise in adults?
spinal cord
Medulloblastomas arise from what type of cell?
Undifferentiated neuroectodermal cells
Where do neuroectodermal cells arise?
cerebellum of children- highly malignant
What is the treatment for medulloblastomas?
Sensitive to radiation therapy
Describe the histology of a medulloblasotoma
Sheets of undifferentiated cells with scanty cytoplasm and dark staining nuclei
Meningiomas arise from what type of cell?
usually arachnoid cells
What is the malignancy of a meningioma? Prognosis?
Usually a benign tumor in adults- resection can be curative
What are the characteristic histologic features of a meningioma?
Psammomas and whorls in middle aged girls
What are craniopharyngiomas?
Benign tumors of childhood- often confused with pituitary adenomas-
What are clinical presentations of craniopharyngiomas?
Endocrine dysfunction
Visual symptoms
Hydrocephalus
Calcifications are common
How do craniopharyngiomas appear on CT?
Suprasellar mass with calcifications
What are schwannomas?
Benign tumors of schwann cell origin. Involved cranial or spinal nerves (often CN VIII)
Bilateral acoustic neuromas are found in what disease?
Neurofibromatosis type 2
What is the stain used in Schwannomas?
S100 protein (any cell of neural crest origin stain with S100 protein)
What is the most common source of a metastatic tumor in the CNS?
lung
What is the gene mutated in NF-1?
Gene on 17q11.2
Neurofibromin-GTPase activating protein
What are pathognomonic findings for NF-1?
Plexiform neurofibromas - “bag of worms”
What familial tumor syndrome presents with multiple cutaneous neurofibromas and cafe au lait spots?
NF-1
What gene is mutated in NF-2?
chromosome 22q12
a tumor suppressor gene (merlin)
What clinical symptom is associated with NF-2?
bilateral acoustic schwannomas and multiple meningiomas
Hamartomatous lesions involving multiple organs are characteristic of what familial tumor syndrome?
Tuberous Sclerosis
What is the classic triad of tuberous sclerosis?
Adenoma sebaceum
Seizures
Mental Retardation
What are the two masses in brain in someone with tuberous sclerosis?
Tubers= glioneuronal hamartomas SEGAS= subependymal nodules --> hydrocephalus
What is the CNS lesion associated with VHL?
CNS hemangioblastoma: highly vascularized
Who is the hottest dude in our class?
Steven once he gets his kid jewelry off next Wednesday.
