Figure 1.

Preoperative MRI at 52 and 58 years old: (a) T2-weighted image at 52 years old presenting the maximum section of the mass in sagittal plane; (b) T2-weighted image presenting the maximum section of the mass in the transverse plane; (c) T2-weighted image at 58 years old presenting the maximum section of the mass in the sagittal plane; (d) T2-weighted image presenting the maximum section of the mass in the transverse plane. The average diameters of the major and minor axes on the sagittal plane and the major diameter of the transverse plane increased by 1.23-fold. The tumor volume increased from 27 to 49 mL (1.85-fold) when approximated by the elliptical sphere formula.