A 15-year-old boy experienced a sudden hearing loss in the left ear. Conservative medical treatment failed, and temporal MR imaging revealed a heterogeneously enhancing mass at the left cerebellopontine angle cistern and in the internal auditory canal; therefore, the lesion was regarded as a typical acoustic neuroma. Few days before surgery, an ipsilateral facial palsy developed, and a follow-up MR imaging showed a rapid growth of the previous lesion. The extended translabyrinthine approach permitted surgical removal. And under pathological diagnosis of malignancy, radiation therapy and series of chemotherapy was performed.