Primary temporal fossa dermoid cysts. Characterization and surgical management.

Objective: To detail the characteristics and management of rarely reported and incompletely described dermoid cysts originating in the temporal fossa.

Design: Retrospective case series.

Participants: Five patients ranging from 2 to 38 years of age with a mass in the temporal region (posterior to the lateral orbital rim) participated.

Intervention: Computed tomography (CT) and excisional biopsy were performed.

Main Outcome Measures: Clinical and CT characteristics and surgical outcomes were measured.

Results: Computed tomography showed cystic lesions, originating from the region anterior to the confluence of the greater wing of the sphenoid, frontal, and zygomatic bones. Displacement of the anteriormost portion of the temporalis muscle was common. Three cysts were isolated to the temporalis fossa, while two showed more extensive bony erosion and extension into the cranial and orbit cavities. At surgical excision, gross rupture of the cysts was noted in two cases, and two were completely liquefied. Histopathology showed variable inflammation surrounding all of the dermoid cysts. All patients did well after surgery.

Conclusions: Dermoid cysts may infrequently occur "primarily" in the temporal fossa. Bone involvement and anterior temporalis muscle displacement are common. An origin from the area anterior to the confluence of the greater wing of the sphenoid, frontal, and zygomatic bones is seen. A coronal approach facilitates wide exposure and excision. When dural extension is suggested on CT, neurosurgical assistance may be required.