OCCURRENCE of bundles of perivascular nerve fibers within the spinal cord has long been known and the resemblance of the tinctorial characteristics of the associated myelin sheaths to myelin of peripheral nerves has received comment.1-3 In cases of myelopathy of diverse causes, intramedullary nerve fibers may proliferate to form localized traumatic neuromata4 within the cord substance. The origin of the axons constituting such neuromata has been given variously as the posterior root,5 perivascular nerves,6,7 and central axons,8 including collaterals of motor neuron processes. Unfortunately, perivascular nerve fiber bundles, traumatic neuromata, and the rare true intramedullary spinal cord neoplasms of neurofibroma or Schwannoma type9,10 have not always been clearly separated in published accounts. The purposes of this paper are (1) to report cases of aberrant intramedullary peripheral nerve fiber bundles and traumatic neuromata; (2) to review the literature on traumatic neuromata, neurofibromata, and perivascular