FIG 1. 15-year-old boy who presented with a more than 8-year progressive exophthalmus of the left eye and a mass in the left oral cavity with a similar time course.

A, Contrast-enhanced axial 4-mm section through the skull base and orbits shows an abnormal strongly enhancing mass infiltrating the left cavernous sinus, superior orbital fissure, and orbit, leading to an exophthalmus and expansion of the superior orbital fissure.

B, Contrast-enhanced coronal 4-mm section reveals the infiltration and expansion of the left superior orbital fissure and the orbit; the masticator space, masseter, and temporal muscles are also infiltrated. The left maxillary sinus and the ethmoidal cells show a hypoplastic pattern.

C, Unenhanced coronal T1-weighted MR image corresponding to B shows short T1 signal intensity characteristics of the lesion.

D, Coronal 1.5 mm high-resolution CT section obtained through the skull base shows infiltration of the opening of the enlarged left round foramen to the pterygopalatine fossa (arrowhead), compared with the contralateral normal round foramen. The major sphenoid wing shows a hyperostotic pattern.