[Diploic epidermoid cyst: case report].

We report the case of a diploic epidermoid cyst in the left front-parietal bone of a 70-year-old woman. A skull x-ray showed an osteolytic lesion with a sclerotic border, and CT scan revealed a low/iso-density mass and the destruction of both inner and outer tables. MRI showed hypo-intensity on T1-weighted image, hyper-intensity on T2-weighted imaging and remarkably-strong intensity on the diffusion-weighted imaging. Gadolinium enhancement was seen in the tumor capsule and dura of the peripheral tumor. In the operative view, most of the bone edge was regular with a sclerotic border, but an irregular section was present. The tumor adhered strongly to the dura mater and periosteum. The tumor was totally extirpated with the peripheral skull, dura mater and periost. On the postoperative MRI, gadolinium enhancement of the nearby dura mater and disappeared. We have added a discussion of the radiological features of diploic epidermoid cysts.