Malignant Peripheral Nerve Sheath Tumor in the Anterior Skull Base Associated With Neurofibromatosis Type 1

—Case Report—

抄録

A 36-year-old man presented with a tumor in the anterior skull base manifesting as headache and visual disturbance. Neurofibromatosis type 1 (NF-1) was identified in early childhood in the patient, and also in his father. Subtotal excision of the tumor was performed, leaving the portion extending outside of the cranium. The histological diagnosis was malignant peripheral nerve sheath tumor. Local radiotherapy was instituted postoperatively. Facial paralysis and dysphagia appeared 7 months after the first operation. Magnetic resonance imaging revealed new lesions in the lateral ventricle and around the brainstem. These tumors were also subtotally excised, but the patient died 10 months after the first operation. The tumor very likely originated from the meningeal branch of the trigeminal nerve. Treatment of such tumors developing inside the cranium should include the widest resection possible, followed by irradiation of the entire neuraxis including the spinal cord to inhibit dissemination through the cerebrospinal fluid. Treatment should be started as quickly as possible if the tumor is associated with NF-1, because of the poor prognosis associated with this condition.