Transient global amnesia due to a dominant hemisphere tumor.

Transient global amnesia is generally regarded as a benign syndrome of probable vascular etiology. We describe a man who experienced a single episode of transient global amnesia and subsequently developed a progressive dominant hemispheric syndrome. Neuroradiologic investigations and the patient's subsequent death strongly suggest that his disease was due to a left temporal-parietal mass lesion. Although the syndrome is most often benign, such patients should be examined for mass lesions.