(425) Recurrent Atypical Teratoid/Rhabdoid Tumor Involving the Internal Auditory Canal

Introduction: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, aggressive, embryonal malignant tumor of the central nervous system. This report describes the first known report of AT/RT recurrence involving the internal auditory canal.

Methods: Case report and review of literature

Results: This is a case report of a 3-year-old boy initially presented in 2004 with a posterior fossa tumor. He underwent a suboccipital craniotomy for gross total resection followed by adjuvant chemoradiation. At age 20, he had a recurrence in the spinal canal (C7 to T2) and underwent resection followed by adjuvant chemoradiation. At age 21, surveillance MRI revealed a new enhancing mass in the left IAC, which was not present on prior imaging 3 months earlier. Symptoms included fullness of left ear and mild autophony. Shortly before surgery, the patient experienced left sudden, profound sensorineural hearing loss that mildly improved with high dose steroids. Patient underwent gross total resection of the left IAC mass via a middle fossa approach. Resection of the cochlear nerve was required due to tumor invasion. Final pathology demonstrated scattered nuclear atypia and rhabdoid differentiation consistent with recurrent AT/RT. Adjuvant chemoradiation was administered. Based on a review of the literature, this case represents only the third report of an AT/RT involving IAC, and the first known report of a tumor recurrence in the IAC.

Conclusions: AT/RT is a rare, aggressive, embryonal malignant tumor that can rarely present in the IAC as a primary or recurrent tumor. Given the rarity of AT/RT and its potential involvement of the IAC, this case report fills a significant knowledge gap related to AT/RT and the potential need for neurotologist intervention.