CNS neoplasms Flashcards
Most common site of pediatric vs adult brain tumors
pediatric: 2/3 are in infratentorial space (iie. Cerebellum, brainstem and below). Adult: supratentorial space (cerebrum)
- Know the World Health Organization (WHO) grading system for selected examples of primary CNS neoplasms
Grade 1: low proliferative potential and possibility of cure following surgical resection alone. Grade II: generally infiltrative in nature, and, despite low level proliferative (ie., mitotic) activity, often recur. Grade III: lesions with histological evidence of malignancy, including nuclear atypia and brisk mitotic activity. Grade IV: cytologically malignant, mitotically active, necrosis-prone neoplasms often associated with rapid pre- and post operative disease evolution and fatal outcome
Treatment for grade II tumors
watchful waiting (ie., close-interval neuroimaging scans to detect upgrading) or external beam cranial irradiation, depending on location, clinical features, type and size of lesion
Treatment for grade III tumors
adjuvant radiation and/or chemotherapy
Infiltrative tumors and less infiltrative tumors
Infiltrative: Diffuse astrocytomas of all grades, oligodendrogliomas, neuronal neoplasms, and to a lesser extent ependymomas. Less infiltrative: meningiomas and schwannomas
List types of neuroectodermal tumors
aka. Gliomas: Astrocytoma, Oligodendroglioma, Ependymoma, Ganglioglioma, Medulloblastoma
List types of meningeal and mesenchymal tumors
Meningioma, Schwannoma, Neurofibroma
list types of metastatic tumors to the brain
Breast, Lung, Kidney, GI Tract, Melanoma
WHO grades for pilocytic astrocytoma, diffuse astrocytoma, anaplastic astrocytoma, oligodendroglioma, anaplastic oligodendroglioma and glioblastoma
Pilocytic astrocytoma: WHO grade I
Diffuse astrocytoma: WHO grade II
Anaplastic astrocytoma: WHO grade III
Oligodendroglioma: WHO grade II
Anaplastic oligodendroglioma: WHO grade III
Glioblastoma: WHO grade IVPilocytic astrocytoma: WHO grade I
Diffuse astrocytoma: WHO grade II
Anaplastic astrocytoma: WHO grade III
Oligodendroglioma: WHO grade II
Anaplastic oligodendroglioma: WHO grade III
Glioblastoma: WHO grade IVPilocytic astrocytoma: WHO grade I
Diffuse astrocytoma: WHO grade II
Anaplastic astrocytoma: WHO grade III
Oligodendroglioma: WHO grade II
Anaplastic oligodendroglioma: WHO grade III
Glioblastoma: WHO grade IVPilocytic astrocytoma: WHO grade I
Diffuse astrocytoma: WHO grade II
Anaplastic astrocytoma: WHO grade III
Oligodendroglioma: WHO grade II
Anaplastic oligodendroglioma: WHO grade III
Glioblastoma: WHO grade IV
Pilocytic astrocytoma population, sites, progression,
Most common CNS neoplasm of childhood but not infrequently found also in young adults. Usual sites: cerebellum, optic pathway, hypothalamus, also thalamus, spinal cord, temporal lobe. minimal tendency to progress to higher grades.
Which pilocytic astrocytomas can be completely surgically resected
Gross total resection of a cerebellar lesion can often be achieved whereas it is impossible to achieve gross total resection in the optic chiasm or hypothalamus. Tumors in these locations often require additional therapy beyond surgery, simply because they will slowly continue to grow and cause dysfunction of vital brain areas
Pilocytic astrocytoma pathology
Pathology: Bipolar neoplastic cells with elongated hairlike processes in parallel bundles, Rosenthal fibers (eosinophilic accumulation of intracytoplasmic glial filaments), eosinophilic granular bodies, May be vascular with calcifications. Mass appear well demarcated and cystic
Pilocytic astrocytoma genetics
BRAF fusion with KIAA leads to constitutive activation of BRAF. BRAF is mitogen-activated protein kinase (MAPK) in RAS/RAF/MEK/ERK pathway. Plays key role in cell proliferation, cell survival, differentiation, apoptosis. Oncogene-induced senescence occurs which is favorable for slow growing tumors.
Diffuse astrocytoma population, progression, location
Mean age 30-40s, WHO grade II, may progress to higher grade, Cerebral hemispheres (white matter), rarely posterior fossa
Diffuse astrocytoma pathology
Discohesive monotonous cellular infiltrate in patternless array. Mild hypercellularity, mild nuclear pleomorphism. • Fibrillary, protoplasmic, gemistocytic subtypes •
Occasional microcystic change• Rare mitoses; two or more on small stereotactic biopsies = WHO grade III • no microvascular proliferation or necrosis • Ki67 / MIB1 <4% • Often nuclear p53 IHC+
Diffuse astrocytoma surgically resectable?
No, ill defined borders. Surgery can be used to debulk tumor, but not totally excise the tumor
diffuse astrocytoma genetics
p53 or ATRX mutation, IDH1/2 mutation
Anaplastic astrocytoma population, grade, location
Mean age 45 years, WHO grade III, Cerebral hemispheres in adults
Anaplastic astrocytoma pathology
Higher cellularity, increased nuclear pleomorphism, hyperchromasia, and mitoses compared to WHO grade II astrocytomas • No necrosis or microvascular proliferation • Ki-67 / MIB1 higher than WHO grade II, usually 5-15% •
MOST IMPORTANT USE OF MIB1
is in distinguishing WHO grade II astrocytoma from WHO grade III anaplastic astrocytoma. MIB1 is higher in anaplastic astrocytoma, MIB-1 is present in nucleus of cells in all phases of cell cycle except G0, thus cells with higher mitotic activity have more MIB1
Anaplastic astrocytoma genetics
IDH mutation, p53 mutation and 9p loss
Oligodendroglioma population, grade, location
Mean age of onset is 42 years, WHO grade II, Usually arises in cerebral white matter (frontal > parietal > temporal > occipital)
Oligodendroglioma presentation
seizures- tumor infiltrates cortex
Oligodendroglioma pathology
Low to moderate cellularity occasional mitosis • Regular round nuclei with artifactual perinuclear halo (appear like a fried egg) • Fine capillary network (chicken wire pattern) and focal calcification • Perineuronal satellitosis, often extensive cortical infiltration correlating with seizure activity clinically • Many cases have intermediate or mixed oligodendroglial/astrocytic phenotype
Oligodendroglioma genetics
IDH mutation, 1p/19q co-deletion (loss of heterozygosityP