Fig. 1.

Axial T1-weighted gadolinium-enhanced magnetic resonance (MR) images of patient 8 in Table 1, 2. A : Preoperative MR image demonstrating an enhancing mass lesion at the petrous apex with brainstem compression. B : Postoperative MR image demonstrating a remained mass lesion at petrous apex. C : MR image at 42 months after the operation demonstrating increased the mass. Hydroxyurea was started. After then, the tumor had been a stable disease. D : MR image at 89 months after initiation of hydroxyurea treatment demonstrating more increase the tumor and midbrain was compressed by tumor mass.