Giant intradiploic epidermoid cyst of greater sphenoid wing causing unilateral proptosis and optic nerve compression.

Epidermoids are cystic tumors that arise from aberrant epidermal cells. Intradiploic epidermoids are relatively rare tumors that occur in all bones of the calvarium, temporal and sphenoid bones, paranasal sinuses, and maxilla. We report the case of an intradiploic epidermoid of the sphenoid wing causing severe proptosis and visual loss. Theories of embryogenesis and pathophysiology are discussed.