Mature teratoma arising from the middle cranial fossa.

A 25-year-old man presented with a sudden spurt in size of a bony swelling around the external ear, which was present since birth. This was associated with a painful swelling of the right half of the face and pain, redness, and decreased vision in the right eye. Neurologic examination showed decreased visual acuity in the right eye and paresis of the fifth, seventh, and eighth cranial nerves. Neuroimaging showed an extra-axial, partly cystic tumor of mixed density, located entirely within the middle cranial fossa scalloping the temporal bone and extending into the right infratemporal fossa and the right middle ear and impinging on the ipsilateral cavernous sinus. The right temporal lobe was elevated and compressed. Histopathologic examination confirmed a mature teratoma.