Hyperostosis is a volume-unit osseous increase of very diverse etiology. We present the case of a 68-year woman with a cranial hyperostosis debuting with frontal protrusion, headache and neurologic symptoms. Image proves demonstrated a hyperostosis in the calotte and meningeal enhancement, without intracerebral lesions nor malignant cells in the cerebrospinal fluid. Analytic data were unspecific. Cranial biopsy showed huge neoplastic infiltration in bone and meninges. Primary site remained unknown after a CAT and a mammography.