The simultaneous occurrence of multicystic encephalomalacia of the cerebral hemispheres, and symmetric necrotizing lesions of diencephalic and infratentorial structures is described in a 15 month-old infant. The baby developed clonic jerks of four limbs a few hours after delivery. She attained no developmental milestones, and remained bed-ridden with hypertonic posture until her death. Multicystic cavities of the cerebral hemispheres were well evident at CT scan when she was 7 months old. The topographic distributions of the different pathological pictures are described; their relationship to the regional properties of the developing brain are commented upon. Etiological aspects of this case are discussed according to present knowledge of the pathophysiological mechanisms leading either to multiple cyst formation or to necrotizing lesions.