opathologic findings and extent of tumor. Craniopharyngioma Originates from remnants of Rathkes pouch above the sella, depressing the optic chiasm. May present at any age but usually in childhood, with endocrine dysfunction and bitemporal field defects. Treatment is surgical, but total removal may not be possible. Acoustic neurinoma Ipsilateral hearing loss is most common initial symptom. Subsequent symptoms may include tinnitus, headache, vertigo, facial weakness or numbness, and long-tract signs. (May be familial and bilateral when related to neurofibromatosis.) Most sensitive screening tests are MRI and brain stem auditory evoked potential. Treatment is excision by translabyrinthine surgery, craniectomy, or combined approach. Outcome is usually good. Meningioma Originates from the dura mater or arachnoid; compresses rather than invades adjacent neural structures. Increasingly common with advancing age. Tumor size caries greatly. Symptoms vary with tumor site. Tumor is usually benign and readily detected by CT scanning; may lead to calcification and bone erosion visible on plain x-rays of skull. Treatment is surgical. Tumor may recur if removal is incomplete. Primary cerebral lymphoma Associated with AIDS and other immunodeficient states. Presentation may be with focal deficits or with disturbances of cognition and consciousness. May be indistinguishable from cerebral toxoplasmosis. Treatment is by whole-brain irradiation; chemotherapy may gave an adjunctive role. Standard Therapy To date, the best treatment for malignant astrocytoma and glioblastoma multiforme (GBM) is a combination of: Surgery (Gross total removal, i.e. 80 99%) Radiotherapy (5,000 6,000 Rads) Chemotherapy (BCNU) Growth Dynamics (GBM): Growth Fraction = 20% (Only a percentage of the tumor is growing at any one time) Cell Cycle Time = 2 5 Days (This is how long it takes a growing cell to reproduce) Cell Loss = 80 90% (A high percentage of cells spontaneously...
