Indications for stereotactically-aided differential diagnosis: the neurologist's view.

The contribution of stereotactic biopsy (SB) in three pathological conditions; neoplastic disease, immunodeficiency states and degenerative cerebral atrophy, is reviewed. When craniotomy is contraindicated, SB is the most reliable method for demonstrating the neoplastic nature and the degree of malignancy of an intracranial space occupying lesion and may help to delineate it limits. In immunodepressed patients, SB is frequently used to differentiate tumours from opportunistic infections. In degenerative dementia, SB is susceptible of differentiating Alzheimer's disease from other degenerative conditions.