Orbital intradiploic giant epidermoid cyst.

We report a case of an intradiploic epidermoid cyst of the lateral orbital wall that resulted in proptosis and downward displacement of the left eye. Computed tomography and magnetic resonance imaging revealed a bone-destroying mass involving the frontal, sphenoid, and zygomatic bones that extended into the orbit, temporalis, and anterior cranial fossa. Complete surgical removal was performed through a lateral orbitotomy. The lateral wall was reconstructed with a porous polyethylene sheet. The cyst has not recurred after 18 months of follow-up.