Overview Presentation Most common complaints are due to mass effects e.g., seizures, dementia, focal lesions, headache majority of adult primary tumors are supratentorial majority of childhood primary tumors are infratentorial Primary tumor characteristics rarely undergo metastasis usually poorly circumscribed primary brain tumor frequency meningioma > pituitary tumor > glioblastoma > nerve sheath tumor risk factors NF, cigarette smoking, Turcot's syndrome (colonic polyps and brain tumor) Secondary tumor characteristics 50% of adult brain tumors are due to metastases well circumscribed usually present at gray-white junction frequency of primary tumor causes lung > breast > melanoma (skin) > kidney > GI Adult peak-incidence tumors Glioblastoma multiforme type: grade IV astrocytoma prognosis: grave (< 1 year life expectancy) location: cerebral hemispheres stain: GFAP histologic appearance: "psuedopalisading" pleomorphic tumor cells border central areas of necrosis and hemorrhage gross appearance: can cross corpus callosum (butterfly glioma) note: may arise de novo or progress from a lower grade astrocytoma methylation of MGMT gene is a positive prognostic factor for survival Meningioma prognosis: resectable location: convexities of hemispheres , parasagittal region, olfactory groove arises from arachnoid cells covering brain histological appearance: spindle cells concentrically arrange in a whorled pattern psammoma bodies (laminated calcifications) note: more common in women (due to estrogen receptors on tumor cells) associated with neurofibromatosis Schwannoma prognosis: good, resectable location: often localized to CN VIII → acoustic schwannoma usually found at cerebrellopontine angle can present with tinnitus, hearing loss staining: S-100 positive histologic appearance: biphasic with hypercellular (Antoni A) and hypocellular (Antoni B) areas note: bilateral schwannoma found in neurofibromatosis type 2 Oligodendroglioma prognosis: good, slow growing location: most often in frontal lobes histologic appearance: chicken-wire capillary pattern with "fried egg" cells round nuclei with clear cytoplasm gross appearance: often calcified in frontal lobe Childhood peak-incidence tumors Pilocytic (low-grade) astrocytoma type: grade I astrocytoma prognosis: benign location: most often infratentorial may be supratentorial (most commonly, craniopharyngioma) stain: GFAP histologic appearance: Rosenthal fibers eosinophilic corkscrew fibers gross appearance: cystic + solid, usually well-circumscribed Medulloblastoma most common malignant intracranial tumor of childhood prognosis: poor, highly malignant form of primitive neuroectodermal tumor (PNET) location: cerebellum can compress 4th ventricle → hydrocephalus histologic appearance: rosettes with small blue cells gross appearance: solid note: radiosensitive Ependymoma prognosis: poor location: most commonly in 4th ventricle can result in hydrocephalus can also arise from cauda equina in adults arises from ependymal cells histologic appearance: characteristic perivascular pseudorosettes Hemangioblastoma (occurs typically in adults if no genetic predisposition as below) location: cerebellar histologic appearance: foamy cells and high vascularity note: associated with von Hippel-Lindau syndrome when found with retinal angiomas can produce EPO → secondary polycythemia Craniopharyngioma prognosis: benign location: near sella turcica can present with optic chiasm compression → bitemporal hemianopia confused with pituitary adenoma derived from remnants of Rathke's pouch gross appearance: calcification is common, tooth enamel-like Germinoma prognosis: good location: pineal gland and suprasellar region derived from nests of embryonic cells arrested during their migration in fetal development Pineal region: Parinaud syndrome (30-40% of cases) compression of tectum causes: paralysis of upward gaze, loss of light perception and accomodation, nystagmus, failure of convergence Suprasellar region: anterior hypopituitarism, precocious puberty, diabetes inspidius, visual disturbances stain: AFP and b-HCG