Case Report: Metastasis of a Trigeminal Malignant Peripheral Nerve Sheath Tumor to the Corpus Callosum.

BACKGROUND AND IMPORTANCE: Malignant peripheral nerve sheath tumors (MPNST) are relatively rare tumors of peripheral nerves that are notable for their locally aggressive nature, ability to metastasize, poor prognosis, and association with Neurofibromatosis type I. We present the case of a patient with a trigeminal nerve MPNST who developed an unusual metastasis to the corpus callosum, in the absence of any other central nervous system or systemic metastatic disease. We review the pathology and presentation of MPNST. CLINICAL PRESENTATION: A 53-yr-old woman presented with a 1-yr history of paroxysmal facial pain and dysesthesias in the right V1 and V2 distributions of the trigeminal nerve. She was initially diagnosed with trigeminal neuralgia although further imaging showed a cavernous sinus mass extending along the trigeminal nerve. She later developed an isolated lesion in the corpus callosum that was biopsied and consistent with MPNST. CONCLUSION: This case reviews the pathology and aggressive nature of MPNST and demonstrates an unusual site of metastasis. Clinicians should remain aware that MPNST can metastasize to sites in the central nervous system as well as systemically. Furthermore, clinicians should have a high index of suspicion for secondary causes of trigeminal neuralgia in cases with atypical features.