Spinal Myxopapillary Ependymoma Metastatic to Bilateral Internal Auditory Canals

Abstract

We report a rare case of spinal myxopapillary ependymoma metastatic to both internal auditory canals (IACs) and its implications for diagnosing neurofibromatosis type 2 (NF2). We present a detailed clinical history, magnetic resonance imaging (MRI), intraoperative photographs, and histopathologic findings from a patient with bilateral IAC lesions, and review the diagnostic criteria for NF2. An 11-year-old boy with surgically resected spinal myxopapillary ependymoma, treated with total spine irradiation for recurrence, later showed bilaterally enhancing IAC lesions on T1-weighted MRI with contrast. The diagnosis of NF2 with bilateral vestibular schwannomas was entertained. Close examination of T2-weighted MRI, however, demonstrated the masses to be isointense to cerebrospinal fluid. This finding raised the possibility of other, more unusual IAC lesions. The patient underwent sequential suboccipital craniotomies for tissue diagnosis, and both IAC lesions were found to be myxopapillary ependymomas. This is the youngest reported patient with metastatic myxopapillary ependymoma. Although vestibular schwannomas account for the majority of contrast-enhancing T1-weighted IAC lesions, other uncommon lesions may present in a similar manner. A T2 fast-spin echo screening MRI would have missed this patient's lesions. Therefore, both T1-weighted MRI with or without contrast and T2-weighted MRI may be necessary to distinguish vestibular schwannoma from other, more unusual IAC lesions.