During the third quarter of her pregnancy, a young woman with Sturge-Weber angiomatosis had a severe right hemiplegia with hemianopia and aphasia, followed 48 hours later by focal seizures. Neuroimaging did not show any cerebral lesion but contrast magnetic resonance imaging revealed a left hemispheric pial angiomatosis. The patient recovered progressively from the third day after a ceasarean. The hemianopia disappeared within 15 days, the hemiplegia within one month and the aphasia greatly improved within 3 months. Ten weeks after the clinical onset, we performed a positron emission tomography study. A decrease from 15 to 40% of the cerebral radioactivity was observed after injection of water (H2(15)O) or fluorodesoxyglucose (18FDG) in the left temporooccipital area adjacent to the meningeal angiomatosis. A chronic and focal olighemia, already reported in Sturge-Weber angiomatosis, might participate in the occurrence of this cortical metabolic depression.