Triphasic waves in cerebral carcinomatosis. Another nonmetabolic cause.

A 59-year-old woman with a metastatic adenocarcinoma of unknown origin and no metabolic abnormalities developed a diffuse encephalopathy, with generalized triphasic waves seen on the electroencephalogram. Postmortem examination revealed widespread, multifocal perivascular carcinomatosis of the cerebral cortices. Triphasic waves have been described with dementing processes, subdural hematomas, and cerebrovascular disease, but they are more commonly seen with metabolic encephalopathies. This case demonstrates an additional nonmetabolic cause of triphasic waves.