Fig. 3

Illustrated surgical result of case No. 2. The initial MRI scan as shown in Fig. 1 in axial (Fig. 1a) and sagittal (Fig. 1b) CT image after surgery (a) demonstrated residual tumor at S4 (star). The residual tumor was gradual increase in size as shown in MRI images (b, c). The surgical removal of remaining mass was performed and revealed large seroma after surgery (d) which gradually resolved at 21 months, postoperatively (e)