A rare case of fibrosarcoma of the scalp following postoperative radiotherapy for medulloblastoma is reported. A review of similar cases in the literature was undertaken in an attempt to find a correlation between the dose of radiation, the length of the latent period, and the nature of the neoplasm. A significantly shorter latent period was found for sarcomas. No relationship was observed between the radiation dose and the latent period. The present case is unique in that the post-irradiation neoplasm (PIN) occurred in a predominantly extracranial site after treatment for a desmoplastic medullobastoma and had a remarkably short latent period.