A case report of inflammatory pseudotumor involving the clivus: CT and MR findings

Abstract

The authors describe a rare case of inflammatory pseudotumor involving the clivus, where a soft tissue mass lesion, with extension into the prevertebral retropharyngeal space and the cavernous sinuses, was detected by CT and MRI. The mass resembled a malignant tumor or aggressive infectious lesion, and the final diagnosis of inflammatory pseudotumor was a diagnosis of exclusion, decided after histopathological examination.

Fig. 1

A 42-year-old male patient who presented with a two-month history of headache and a four-day history of diplopia. A. T2-weighted axial MR image at the level of the sphenoid sinus shows very low heterogeneous signal intensity involving the clivus and bilateral cavernous sinuses, with sphenoid sinusitis (arrows). Note the narrowing of the cavernous part of the right internal carotid artery (arrowhead). B. T2-weighted axial MR image at the level of the nasopharynx shows a high signal intensity lesion in the prevertebral muscles (arrowheads) and a heterogeneous mixed high and low signal intensity lesion in the clivus (arrows). C. T2-weighted mid-sagittal MR image reveals an expansile heterogeneous low signal intensity lesion involving the entire clivus (arrows). Note the presence of an apparently normal pituitary gland and intact sellar floor. D. T1-weighted mid-sagittal MR image at the same level as C shows mixed intermediate and low signal intensity replacing the entire clival bone marrow. The posterior line of the cortical dark signal has been destroyed (arrows). E. Contrast-enhanced T1-weighted sagittal MR image at the same level as C demonstrates strong enhancement of the lesion (arrows), with small nonenhancing areas. F. Contrast-enhanced T1-weighted coronal MR image at the level of the pituitary stalk shows bilateral involvement of the cavernous sinuses associated with narrowing of the cavernous portion of the right internal carotid artery due to infiltration of the lesion (arrows). G. Coronal bone algorithm CT scan obtained at the level of the pituitary gland shows permeative bone destruction of the clivus (arrows). H. Pathologic specimen obtained from the clivus shows thick fibrous bands with scattered chronic inflammatory cells (H&E staining, original magnification ×100).