Fig. 2

Magnetic resonance imaging of the pelvis with contrast performed for further evaluation of the soft tissue abnormality seen on computed tomography (Fig. 1). (i) Sagittal T2WI demonstrates soft tissue thickening in the presacral space (yellow arrow). Post-contrast fat-saturated axial T1WI ((ii)) and (iii) demonstrate enhancing soft tissue in the left pelvic side wall, left mesorectal fat, and extending through the greater sciatic foramen (blue arrow). (iv) Soft tissue could be seen to extend toward the left L5/S1 exiting neural foramen with involvement and thickening of the exiting left-sided sacral nerve roots (green arrow), lumbosacral plexus and ipsilateral sciatic nerve