Tangled masses of regenerated central nerve fibers (non-myelinated central neuromas) in the central nervous system.

Tangled masses arising from central nerve fibers and resembling non-myelinated neuromas (central neuromas) are described in five patients. The masses occurred together with neuromas of peripheral nerve fibers (peripheral neuromas) in the midbrain, associated with a cystic infarct in one patient and in the spinal cord with old traumatic injury in two other patients. In the remaining two patients, central neuromas occurred alone in the pons or midbrain, associated with a small old infarct in the former and perivenous encephalomyelitis in the latter. Central neuromas are distinct from the myelinated or unmyelinated peripheral neuromas, for they not only lack myelin sheaths. Schwann cells, and reticulum fibers, but also are unrelated to blood vessels. The observation of central neuromas, hitherto unrecognized, indicates that certain central axons, particularly those in the brain stem and spinal cord, have sufficient capacity to regenerate, much as peripheral nerve fibers.