Malignant Peripheral Nerve Sheath Tumor of the Abducens Nerve and a Review of the Literature

Abstract

Malignant peripheral nerve sheath tumors are rare, and intracranial occurrences are even more rare. Treatment strategies have varied widely. This article reports the first case of a malignant peripheral nerve sheath tumor of the abducens nerve and provides a literature review that includes 61 cases of intracranial malignant peripheral nerve sheath tumors. Data were analyzed based on age, sex, treatment, survival, immunohistochemical staining, location, tumor grade, and neurofibromatosis association. These tumors more often affect male persons, and the patients affected have a mean age of 39 years. Most patients underwent subtotal or gross total resection and radiation. Intracranial location varied, but most tumors occurred in the cerebellopontine angle. The literature shows that intracranial malignant peripheral nerve sheath tumors are a heterogeneous group. Their association with neurofibromatosis is less clear than that of their extracranial counterparts. Prognosis is poor, but surgical resection and radiation can enhance chances for longer survival. Our aim was to elucidate information about these tumors. A 30-year-old woman presented with a 6-month history of headaches and diplopia. Neurological examination revealed no focal deficit. Imaging revealed a heterogeneously enhancing retroclival mass without bony destruction. The tumor originated from the ipsilateral abducens nerve and extended into the Dorello canal; it adhered to the brainstem and cranial nerves. Pathology was consistent with low-grade malignant peripheral nerve sheath tumor. At 3-month follow-up, the patient walked with a cane with no further deficits except mild ataxia, which resolved within 6 months. Magnetic resonance imaging revealed a small residual tumor adherent to the basilar artery. At 1-year follow-up and after ocular surgery to correct lateral rectus palsy, the patient was neurologically intact.