[Intradiploic epidermoid cyst: diagnosis by ultrasonography and MRI].

Epidermoïd cysts are well documented. Whenever possible, surgery is always necessary. Intradiploic epidermoïd cyst are uncommon, especially in the occipital bone. Ultrasonography (US) may be useful and used instead of radiographs. As demonstrated in intracranial forms, diffusion-weighted MR Imaging (MRI) sequence can be useful for the diagnosis of epidermoid tumors and postoperative assessment of residual tumor. We propose to illustrate the usefulness of US and MRI in depicting an intradiploic epidermoïd cyst in a 27-year-old woman.