Dermatofibrosarcoma protuberans (DFSP) originates from the dermal layer of the skin; the optimum treatment is an extended marginal resection. We describe a case of DFSP of the scalp with a skull invasive defect that was thoroughly examined pathologically to determine the optimum length of surgical margins. The tumor cells infiltrated up to 26 mm into the dermal tissues, whereas no infiltrating tumor cells were present in the skull, indicating the combination of marginal resection of the dermal tissues and lower of the skull can be a clinically relevant strategy for treatment of DFSP cases with skull invasion.