Pilocytic astrocytoma of a spinal nerve root. Case report.

A case of pilocytic astrocytoma involving a spinal nerve root is reported. A 39-year-old woman presented with a 1-year history of progressive pain and numbness, predominantly in the S-1 dermatome. Magnetic resonance (MR) imaging revealed an intradural lesion at the tip of the conus medullaris. The intradural tumor was excised as was the sacrificed nerve root. Histological examination showed a pilocytic astrocytoma in which there were unusual features of calcification and ossification. At 3-year follow-up review MR imaging demonstrated no residual tumor. To the best of the authors' knowledge, this is the first case of a primary pilocytic astrocytoma, a tumor typically of central nervous system origin, arising from a spinal nerve root.