OBJECTIVE We present a rare case of desmoplastic fibroma of the skull. Desmoplastic fibroma is a distinctive and rare neoplasm of bone that histologically and biologically mimics desmoid soft tissue tumor. Only 6 cases have been reported in the skull and none of these was diagnosed by MRI. METHODS A 64 year-old woman, operated on in June 1991 for left mastectomy due to a ductal adenocarcinoma and again in October 1994 for a left frontal metastatic adenocarcinoma, was admitted in our Department of Neurosurgery because a control cerebral MRI had detected a diploic lesion, isointense on T1-weighted images and hyperintense on T2, with moderate enhancement, localized in a right parietal site. Neurological examination was negative. The lesion was surgically removed and a cranioplasty was performed. Histological diagnosis was desmoplastic fibroma. Twelve months after treatment she has no neurological symptoms or signs of cerebral lesions (MRI) or systemic metastasis (total body CT). CONCLUSIONS In the literature the number of desmoplastic fibroma is too small and the follow-up period too short to permit any conclusions regarding the aggressiveness of the tumor.