DIFFERENTIATION of stroke from brain tumor, made on the basis of historical data and neurologic findings, is speculative at best. Variations in the clinical pattern of each condition are so infinite that the usual criteria relied upon for selection of surgical candidates are too frequently misleading. Patients with occlusive cerebral disease may manifest gradual or recrudescent development of seizures, hemiparesis, hemianopsia, or aphasia, and may occasionally show papilledema.1 The precipitous onset of symptoms in some cases of brain tumor is common experience and is often explained by aberrant vascular phenomena in relation to a growing neoplasm, i. e., hemorrhage or venous stasis. When the clinical manifestations of these separate pathologic entities are considered simply as outward expressions of altered neurophysiology, the appearance of one in the guise of the other becomes readily understandable. It is to be acknowledged that the differential criteria are reasonably accurate at the extremes of