Extraorbital idiopathic pseudotumors of the skull base are very uncommon. We report the case of a 50-year-old woman who presented with left ophthalmoplegia and vision loss. Imaging studies revealed an enhancing lesion involving the left petrous apex and cavernous sinus. A transnasal endoscopic approach was used to obtain a biopsy of the left petrous apex. Pathology identified the lesion as an idiopathic pseudotumor. The patient was treated with high-dose steroids and steroid-sparing immunomodulators, and she experienced a significant improvement. To the best of our knowledge, this is the first reported case of a transnasal endoscopic approach to a biopsy of a pseudotumor involving the petrous apex. We discuss the features of this case, and we review the literature on this condition.
The term pseudotumor refers to an inflammatory lesion that usually presents in the orbit. This nonspecific collection of inflammation has been reported to represent 5 to 16% of orbital masses in adults.1 In rare instances, idiopathic pseudotumors have been found outside the orbit.