Atypical teratoid rhabdoid tumor in the cavernous sinus of a toddler presenting with oculomotor nerve palsy

INTRODUCTION: Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant, and aggressive tumor of infancy. Although the prognosis of ATRT has been extremely poor, recently, the first prospective study for ATRT demonstrated improvement of prognosis. On the other hands, oculomotor nerve palsy is rare in children and the most frequent etiology is congenital. To our knowledge, only a few ATRT cases presenting with oculomotor nerve palsy have been reported, but ATRT originating from the cavernous sinus (CS) has not yet been reported. CASE REPORT: An 18-month-old girl with right oculomotor nerve palsy was admitted, and a small mass in the right CS was detected with brain MRI. Although she received steroid pulse therapy and antimicrobial therapy, the mass continued to enlarge. One month after admission, the mass was partially resected and diagnosed as ATRT. Multimodal therapy including anthracycline-based chemotherapy, intrathecal therapy, and cranial irradiation was performed. Twenty-nine months after resection, she was alive without tumor relapse, but the oculomotor nerve palsy persisted. CONCLUSION: This is the first reported case of ATRT located in the CS presenting with oculomotor nerve palsy. This case was successfully treated with partial removal of the tumor, a new chemotherapy regimen for ATRT and cranial X-ray irradiation.