Extensive cortical-subcortical damage of the left hemisphere, most likely due to prenatal infarction of the left middle cerebral artery, was accidentally detected in a 12-year-old left-handed girl. Since clinical symptoms were minimal, the lesion had not been discovered for more than a decade. Meticulous examination revealed some slowness and somatosensory deficits of the right hand. Yet, independent finger movements were preserved, and functional skills such as reaching and grasping were unimpaired, as documented with optoelectronic motion analysis. There were no mirror movements. Transcranial magnetic stimulation indicated that the right hand was controlled by spared cortical areas of the damaged hemisphere. Gait was normal. Neuropsychological examination confirmed regular development of language, intellect, and visuospatial abilities. This case report demonstrates exceptionally good functional outcome after early brain damage.