The authors report the case of a man who had suffered a penetrating metal splinter injury to the left frontal lobe at 18 years of age. Thirty-seven years later the patient developed a left-sided frontal tumor at the precise site of the meningocerebral scar and posttraumatic defect. Histological examination confirmed a glioblastoma multiforme adjacent to the dural scar and metal splinters. In addition, a chronic abscess from which Propionibacterium acnes was isolated was found within the glioma tissue. The temporal and local association of metal splinter injury with chronic abscess, scar formation, and malignant glioma is highly suggestive of a causal relationship between trauma and the development of a malignant brain tumor.