SOLITARY FIBROUS TUMOR OF THE SPINAL-CORD

We report a case of primary solitary fibrous tumor occurring in the in tramedullary thoracic spinal cord in a 47-year-old man. The tumor pred ominately consisted of spindle cells separated by abundant collagen; a few areas of hemangiopericytomatous morphology were also present. The diagnosis was confirmed by immunohistochemistry and electron microsco py. The tumor was reactive to vimentin and CD34 but was negative for g lial fibrillary acid protein (GFAP), S-100, smooth muscle actin, epith elial membrane antigen, HMB-45, myelin basic protein, and keratin; ult rastructural examination showed fairly undifferentiated cells within a collagenous matrix, few tight junctions, and sparse extravascular bas ement membrane. The occurrence of this tumor within the spinal cord pa renchyma and in other extraserosal sites emphasizes the current belief that solitary fibrous tumors arise from mesenchymal tissues and are n ot restricted to the pleura and other serosal surfaces. Furthermore, s olitary fibrous tumor is an entity that must be considered in the diff erential diagnosis of spindle cell central nervous system neoplasms.