Extraorbital Skull Base Idiopathic Pseudotumor

Abstract

The term idiopathic pseudotumor (IP) refers to a nonspecific, nonneoplastic inflammatory process without identifiable local or systemic causes, which is one of the most common causes of intraorbital space-occupying lesions. Occasionally, orbital pseudotumors may extend to other areas of the skull base. Rarely, pseudotumors may present as a skull base mass with no involvement of the orbit. The ophthalmology literature has detailed reviews of IP as an intraorbital space-occupying lesion, but lesions involving only the skull base and sparing the orbit are rare in the literature. We present a review of our experience with six patients with extraorbital skull base pseudotumor and a review of the relevant literature. Retrospective case study. We treated six patients with extraorbital skull base pseudotumor between 1996 and 2004. Four patients had lesions in the pterygopalatine and/or infratemporal fossae, and two patients had lesions in the superior aspect of the parapharyngeal space. Five patients had excellent initial response to steroids. Two of the pseudotumors recurred. One patient partially responded to steroids and is currently stable with limited disease. Our literature review demonstrated 16 previously published reports of IP of the skull base sparing the orbit. A well-documented intraorbital lesion, inflammatory pseudotumor may present outside the orbit. Treatment of IP of the skull base is controversial and may involve corticosteroids or surgical resection, or both. Other chemotherapeutic agents and radiotherapy may be considered in steroid-resistant patients. Pathological subtype, ease and safety of resection, safety of high-dose corticosteroid use, the surgeon's comfort, and the patient's preference must be included in the decision-making process for treatment.