Unusual CT and MR findings of inflammatory pseudotumor in the parapharyngeal space: case report

Abstract

Unusual MR and CT findings of an inflammatory pseudotumor in the parapharyngeal space of a 73-year-old woman are reported. The mass was hypointense on T1- and T2-weighted images and demonstrated ring enhancement after contrast medium injection. Punctated calcifications were scattered at the periphery. Inflammatory pseudotumors in the parapharyngeal space are rare, and only three cases have been reported. The possible pathogenesis and varieties of inflammatory pseudotumors are discussed.

fig 1.

A 73-year-old woman with IPT of the parapharyngeal space. A, Axial T2-weighted MR image at 5000/102/2 (TR/TE/excitations) reveals a well-circumscribed, mixed, but markedly hypointense mass in the right parapharyngeal space. A ringlike hyperintense area (white arrows) in the circumferential portion of the mass was noted. B, Axial T1-weighted image at 600/16/2 shows a well-marginated, hypointense mass associated with a peripheral ringlike, high–signal-intensity area (black arrowheads). The right pterygoid muscles are displaced anteriorly. C, Axial T1-weighted image at 600/16/2 after intravenous injection of gadopentetate dimeglumine shows moderate enhancement (black arrowheads) in the peripheral portion of the mass, corresponding to the hyperintense ring on T2-weighted images. D, Contrast-enhanced CT scan obtained after biopsy shows a well-defined hypodense mass scattered with punctate calcifications at the periphery. Note several air bubbles within the mass, probably induced at biopsy. E and F, Microphotographs of the surgical specimen (hematoxylin and eosin stain) reveals granulation tissue containing giant cells, abundant hyalinized fibrosis, collagenous deposits, marked infiltration of mostly lymphocytes, and histiocytic proliferation (E, original magnification ×30). A moderate number of the vessels are present in the inflammatory infiltrates in the peripheral portion of the mass (F, original magnification ×150).