Herpes simplex virus encephalitis simulating a frontoparietal convexity neoplasm.

The unusual occurrence of a single, cell circumscribed encephalitis due to herpes simplex virus in the frontoparietal convexity is described and served to underline the importance of considering this pathology in the event of a rapidly expanding lesion presenting in any portion of the brain. The valuable, but limited, usefulness of brain scanning and cerebral angiography in making this diagnosis is discussed. Neurosurgical intervention and brain biopsy are required to make the definitive diagnosis.