Transient enlargement of deep medullary veins in encephalitis.

This case report concerns a woman who presented an atypical clinical pattern with some features of encephalitis and other features of brain tumor. Cerebral angiography showed a unilateral cerebral mass with prominence of deep medullary veins, usually interpreted as evidence of a neoplasm. Brain biopsy was interpreted as astrocytoma. Subsequent spontaneous clinical remission and regression of angiographic findings led to a reappraisal of the microscopic interpretation with a final diagnosis of encephalitis. The pathogenesis of cerebral angiographic abnormalities observed with encephalitis is reviewed. The transient prominence of deep medullary veins is probably due to hyperemia. Followup angiography is recommended when encaphalitis is suspected.