Rare giant epidermal cyst in the infratemporal fossa and middle cranial fossa.

A 50-year-old man presented with a rare giant crossing cranium-temporal combined epidermal cyst. Physical examination found left facial numbness and temple severely numbness with light pressure. Horizontalis craniocerebral computed tomography demonstrated a mass lesion of 3.0 × 2.0 cm in the middle cranial fossa area; sagittal craniocerebral magnetic resonance scanning demonstrated a mass consisting of 2 leaves (the upper one, 4.0 × 3.0 cm; the lower one, 2.0 × 1.5 cm). Computed tomography angiography showed that the blood supply of the lesion came from superficial temporal artery and middle cranial fossa artery. The clinical diagnosis was neurilemmoma. Surgery revealed a pearly cyst consisting of 2 leaves (connected by a narrowed bridge located at the articular fossa of temporal bone) was 6 × 3 × 3 cm. Histologic examination disclosed disintegrated keratinizing epithelium layer, keratinizing epithelium layer, and stratified squamous epithelium layer from inner to outer and found no hair follicles or sebaceous gland with the diagnosis of epidermoid cyst. Surgery was successfully performed, and the patient was discharged home with severer left facial numbness relatively and left jaw slight opening. The present case suggests that epidermoid cysts can be seen in any location, even giant crossing cranium-temporal combined lesion, and the blood supply should be considered as a factor judging its pathogenesis.