Giant epidermoid involving 3 cranial bones.

We describe a patient with an incidental finding of an expansile osteolytic lesion centered in the sphenoid involving 3 cranial bones-frontal, temporal, and sphenoid-and invading the brain parenchyma and orbit. Biopsy demonstrated an epidermoid. The lesion was excised through frontotemporal craniotomy. Despite the benign nature of the tumor, the epidermoid had a destructive pattern of growth. Complete resection was needed to adequately address the inflammatory mass effect of the large lesion.