Inflammatory Pseudotumor of the Extraorbital Head and Neck: CT and MR Imaging Findings

Abstract

Purpose: To determine the MR and CT imaging findings of inflammatory pseudotumor of the extraorbital head and neck. Materials and Methods: We reviewed the MR (n=10) and CT (n=9) imaging studies of 11 patients with this condition (M:F=5:6, age range: 35-75 years), analysing each case in terms of location, occupying space, signal intensity, intracranial involvement, degree of contrast enhancement and adjacent bone change. Follow-up images were obtained in nine cases, and the response of each patient to steroid treatment was reviewed. Results: Lesions involved the masticator space (n=8), the buccal space (n=6), the nasopharynx (n=5), the paranasal sinus (n=4), the parapharyngeal space (n=3), the prevertebral space (n=2), the orbit (n=2), the carotid space (n=2), the paravertebral space (n=1), parotid space (n=1), and the oral cavity (n=1). In ten of eleven cases, there was adjacent bone change. In three cases, the cavernous sinus was involved, and in two, the dura. One case involved both of them. At T2-weighted imaging, the lesions showed hypointensity in nine of ten cases; in four of nine, signal intensity was markedly low, and in no case was it diffusely high. In five of nine cases, the mass decreased in size after steroid therapy. Conclusion: Inflammatory pseudotumor showed iso-to hypointensity at T2-weighted imaging. Lymphadenopathy was not apparent.