Leptomeningeal metastasis of an intradural malignant peripheral nerve sheath tumor.

Malignant peripheral nerve sheath tumors (MPNST) are defined as any malignant tumor arising from or differentiating towards the peripheral nerve sheath. Intradural MPNST metastases are very rare. We report, to our knowledge, the first case of leptomeningeal metastasis of a MPNST to the spine and intracranial space. A 56-year-old woman with primary intradural MPNST of the S1 nerve root developed leptomeningeal metastases as well as brain metastases 19 months after diagnosis. The patient had a history of non-Hodgkins lymphoma for which she had received irradiation to the spine 15 years prior to this presentation. She had no stigmata of neurofibromatosis type 1. Patients with MPNST may also develop leptomeningeal metastases as demonstrated in this patient with intradural post-radiation MPNST.