Inflammatory pseudotumor in the epidural space of the thoracic spine: a case report and literature review of MR imaging findings

Abstract

We present a rare case of pathologically proven inflammatory pseudotumor in the thoracic spine. The lesion showed an isointense signal on T1-weighted images, a heterogeneous iso- and hyperintense signal on T2-weighted images, and strong homogeneous enhancement. There was no evidence of abnormalities in the adjacent bone. Whereas the exact pathogenesis of this lesion is unknown, it has been regarded as an unusual response to insults such as trauma or acute infection, a post-inflammatory reparative process, or low-grade malignancy.

Fig 1.

Thoracic spine CT scan shows an epidural mass compressing the spinal cord without bony destruction.

Fig 2.

MR imaging demonstrates the expansile epidural mass from T1 to T7, showing heterogeneous iso- and hyperintensity on the sagittal T2-weighted image (A) and homogeneous isointensity on the T1-weighted image (B). The postcontrast sagittal (C) and axial (D) images reveal a homogeneous enhancing lesion with cord compression. There is no abnormality in the adjacent bone.

Fig 3.

Microscopically, there is a polymorphic infiltrate composed of plump myofibroblasts (arrows) and lymphoplasma cells in loose fibromyxoid stroma, suggesting inflammatory myofibroblastic tumor (hematoxylin and eosin, original magnification ×100).

Fig 4.

A, Abundant inflammatory cells such as plasma cells (arrow) in rich vascular stroma are seen in some areas (hematoxylin and eosin, original magnification ×200.) B, Paucicellular area shows platelike collagen resembling scar tissue (hematoxylin and eosin, original magnification ×200).