CNS Tumors Flashcards
circumscribed grade I astrocytoma
Most common in children and adolescents
Commonly affects cerebellum, diencephalon (hypothalamus, optic nerve/chiasm)
Often cystic with tumor nidus in the cyst wall (mural nodule)
Not diffusely infiltrative of the surrounding brain
Amenable to complete surgical excision long term survival/cure
Biphasic microscopic pattern
Fascicles of elongated spindle cells with coarse cytoplasmic processes
Loose microcystic zones
Pilocytic astrocytoma
diffuse astrocytoma grade II
Poor demarcation from surrounding brain with deep extension into neighboring tissue
Complete surgical resection often/usually not possible
Progression of grade II lesions to grade III or IV with time
Brainstem of children or cerebral hemisphere white matter in adults under 40
CT/MRI hypodense lesion without contrast enhancement, minimal/absent edema
Grey-white poorly demarcated mass expanding or effacing normal architecture
No hemorrhage or necrosis
Hypercellularity (increased astrocytes) with nuclear pleomorphism
No mitoses, vascular proliferation, or necrosis
Survival 5-10 years after surgery
Late recurrence often at higher grade
Eventual death from tumor
astrocytoma
diffuse astrocytoma grade III
Poor demarcation from surrounding brain with deep extension into neighboring tissue
Complete surgical resection often/usually not possible
Progression of grade II lesions to grade III or IV with time
Cerebral hemispheric white matter in adult 40-50 years
CT/MRI low density lesion with irregular contrast enhancement, +/- edema
Grey-white poorly demarcated mass expanding or effacing normal architecture
No hemorrhage or necrosis
Hypecellularity, pleomorphism, mitoses
Recurrence in 12-24 months after surgery
Progression to grade IV glioblastoma
Death from tumor
Anaplastic astrocytoma
diffuse astrocytoma grade IV
Poor demarcation from surrounding brain with deep extension into neighboring tissue
Complete surgical resection often/usually not possible
Progression of grade II lesions to grade III or IV with time
Cerebral hemispheric white matter in adults > 50 or the brainstem of children
CT/MRI heterogenous, hypersense lesion, ring enhancing, significant peritumoral edema and mass effect (ventricular effacement, shift of midline structures)
Hemorrhage, necrosis
May cross to the contralateral hemisphere in the corpus callosum (butterfly glioma)
Hypercellualrity, pleomorphism, mitoses, vascular proliferation and necrosis
Necrotic areas are sometimes surrounded by radially arranged still-viable tumor cells (palisade/pseudopalisade)
Death from tumor within 12-24 months
Adjuvant radiation therapy may prolong survival by several months
Glioblastoma multiforme
IV ventricle in children, spinal cord of adults
Myxopapillary variant in the lumbosacral cord of adults has a favorable prognosis (grade I)
Better circumscribed then diffuse astrocytomas but still tend to recur after surgery
CT/MRI heterogeneously enhacing IV ventricular or spinal cord mass, sometimes with calcifications
Solid/papillary intraventricular tumor
Relatively circumscribed intramedullary spinal cord mass
Glial tumor with perivascular pseudorosettes +/- ependymal canals (true rosettes)
Survival depends on age, location, and resectability
Survival is shorter in children, intracranial location, and incomplete resection
Recurrence, dissemination in CSF
Ependymoma
Cerebral hemispheric white matter of adults
CT: calcification is common, may follow cortical ribbon in serpiginous pattern
Gray-pink mass with cysts, calcification, and hemorrhage
Uniform cells with clear cytoplasm and central nuclei (fried eggs) with acutely branching capillary stroma (chicken wire vasculature)
Variable survival, somewhat better than astrocytomas
Survival 5-10 years or longer
Recurrence sometimes at higher grades
Eventual death from tumor
Translocation on 1p/19q
Oligodendroglioma
Cerebellar vermis tumor in children
Originates from primitive precursor cells, probably in the cerebellar external granular cell layer
CT/MRI hyperdense contrast enhancing lesion
Variable circumscription, gray-white to hemorrhagic
Small round blue cell tumor
Cells with very high nuclear:cytoplasmic ratio
Homer Wright rosettes (neuropil in the center)
High mitotis activity, apoptosis, pleomorphism
May show neuronal and/or glial differentiation
Surgery and radiation/chemo increases chances of survival at 5 years to 50-70%
Recurrence, dissemination in CSF
Medulloblastoma
Extra-axial tumor derived from arachnoid cap cell (meningothelial cells) of leptomeninges
Attached to dura over cerebral convexity, falx cerebri, base of the skull (sphenoid wing, petrous ridge, clivus, foramen magnum), spinal canal
Most common in adult females
CT/MRI extra-axial isodense mass with contrast enhancement
May show streak of enhancement trailing off from the main tumor mass (dural tail)
Well circumscribed firm grey-white mass anchored on the dura
Architecture composed of varying proportions of spindles and whorls
Minimal pleomorphism, mitotic activity
May see round concentric calcifications (psammoma bodies)
Slow growth over a long period
May entrap cranial/spinal nerves, blood vessels
May infiltrate dural venous sinuses and overlying bone with secondary bone thickening (hyperostosis)
Progesterone receptors may be present
Allelic losses on chromosome 22
Multiple tumors are characteristic of neurofibromatosis type 2
Meningioma
Extra-axial tumors derived from Schwann cells
Cerebellopontine angle tumor in adults with hearing loss (vestibular Schwannoma) affects CN VIII
Spinal canal, attached to nerve root (usually dorsal) with nerve root compression
Well circumscribed, encapsulated
May show degenerative changes (cysts, hemorrhage)
Biphasic with dense (Antoni A) and loose (Antoni B) zones
Alignment of nuclei in palisades (Verocay bodies) best seen in dense areas
Parent nerve is pushed to one side
Slow growth over long period
Surgically curable
May affect peripheral nerves
Multiple tumors (especially bilateral cerebellopontine angle tumors) characteristic of neurofibromatosis type 2
Schwannoma
Extra-axial tumor derived from Schwann cells
Unencapsulated, diffuse fusiform expansion of nerve
Soft with shiny gelatinous cut surface
Loose myxoid background with small wavy or comma shaped Schwann cell nuclei
Axons of the parent nerve embedded in and separated by tumor
Slow growth over a long period
May affect peripheral nerves and terminal nerve branches in skin
Multiple neurofibromas characteristic of neurofibromatosis type 1 (von Recklinghausen’s disease)
Nerve sheath tumors in NF1 may become malignant
Neurofibroma
CNS is the favored site of metastasis for lung carcinoma, breast carcinoma, malignant melanoma, renal cell carcinoma, gastrointestinal tract carcinoma
Multiple (sometimes single) CNS masses
Grey-white junction of cerebral hemispheres is a favored site but may occur elsewhere
Diffuse spread in subarachnoid space (carcinomatous meningitis)
Dural infiltration (breast and prostate carcinoma)
CT/MRI multiple (or singe) heterogenous masses with contrast enhancement and surrounding edema
Circumscribed tumors with necrosis, hemorrhage
Histology matches primary neoplasm
Influences by number of location of metastases, sensitivity of primary tumor to therapy
Median survival of patients with multiple brain metastases treated with radiation is 3-6 months
Metastatic tumors
