[Osteoblastoma simulating osteosarcoma of the petrous bone].

The case of a 25-year-old patient with a rare osteoblastoma-like osteosarcoma of the pars petrosa is discussed. CT scans (thin layers) showed a lytic, the skull basis-resorbing tumor with slight matrix calcification. MRI demonstrated a mainly signal intense tumor in T1-weighted images with less signal intensity at its borders which showed an enhancing peripheral zone after use of a gadolinium-containing medium.