The authors report cognitive functions of a 13-year-old boy with a cavernous angioma occupying the posterior left parahippocampal gyrus (PHG) and part of the left fusiform gyrus but not hippocampus. Neuropsychological examinations soon after the removal of the tumor showed selective deficits in semantic memory function, as evaluated by the Category Fluency Task and the Wechsler Memory Scale-Revised, while visual memory, attention, and IQ were not affected. These observations suggest the involvement of the PHG in the processing of semantic memory and provide an insight into the neural substrates underlying the distinct cognitive deficits in some of the psychiatric diseases such as schizophrenia.