Unusual fibro-osseous lesion of the spinal cord with positive staining for glial fibrillary acidic protein and radiological progression: a case report.

A rare intradural lesion of the lumbar spine producing leg pain and minimal neurological deficits is described in a 48-year-old man. Previous reports of similar lesions have been described under the designation "fibro-osseous lesions" and "calcifying pseudoneoplasms." This is the first report of an unusual fibro-osseous lesion with an intradural spinal location as well as the first to show immunohistochemical positivity for glial fibrillary acidic protein (GFAP) within cellular components of this process and crystal formation suggestive of calcium pyrophosphate. This case also shows radiographic progression suggesting the possibility that this entity may be a form of low grade neoplasm.