Mesenchymal chondrosarcoma of the cauda equina.

Primary central nervous system mesenchymal chondrosarcomas are extremely rare tumors composed of primitive mesenchymal cells punctuated by islands of cartilage in various stages of differentiation. Although there are isolated reports of tumors arising in the spinal dura, to our knowledge extraskeletal mesenchymal chondrosarcoma localized to the cauda equina has not been reported in the literature. We present an unusual case of a mesenchymal chondrosarcoma involving the nerve roots of the cauda equina. The clinical, pathological and neuroimaging features are reviewed and discussed.