Malignant Peripheral Nerve Sheath Tumor of the Trigeminal Nerve Involving the Middle and Posterior Cranial Fossa

Although benign trigeminal schwannomas are uncommon, malignant peripheral nerve sheath tumors (MPNSTs) of the trigeminal nerve are extraordinarily rare. A 56-year-old female presented with a 2-month-long history of numbness of the right face and progressive weakness of the left limbs. Preoperative neuroimages indicated a giant tumor involving the middle and posterior cranial fossa with similar radiologic characteristics to benign trigeminal schwannomas. However, histopathologic and immunochemical examinations confirmed the tumor to be an MPNST. A nearly gross total resection was obtained with a combined frontotemporal extradural and subtemporal anterior petrosal approach. The postoperative course was uneventful, and the patient received adjuvant radiotherapy subsequently. There was no recurrence of the tumor with a 6-month-long follow-up. MPNSTs of the trigeminal nerve are exceedingly rare. This study described the 21st case of MPNSTs of the trigeminal nerve. MPNSTs of the trigeminal nerve showed similar radiologic characteristics to benign trigeminal schwannomas, and accurate diagnosis depended on pathologic and immunochemical examinations. Gross total resection followed by radiotherapy is the usual treatment. •MPNSTs of the trigeminal nerve are exceedingly rare.•MPNSTs of the trigeminal nerve showed the similar neuroimaging characteristics to benign trigeminal schwannomas.•Accurate diagnosis of MPNSTs of the trigeminal nerve depends on the pathologic and immunochemical examinations.•Gross total resection followed by radiotherapy is the usual treatment for MPNSTs of the trigeminal nerve.