Spinal intramedullary teratoma with exophytic components: report of two cases and review of the literature.

True intramedullary teratoma is an extremely rare tumor, with only seven cases reported in the literature. The authors present two personal cases of spinal intramedullary cystic teratoma of the conus medullaris with exophytic growth and some unusual aspects. Their cases are unusual not only because they were diagnosed by MRI but also because the monitored microsurgical removal of the tumor was apparently total, with excellent results, in clinical and neuroradiologic terms. We recommend early radical surgery whenever possible, when the patient's neurological status is still good. To prevent traumatizing adjacent spinal cord for cases in which the teratoma tightly adheres to the functional neurological tissue of the spinal cord with no cleavage plane, we do not recommend an aggressive surgical attempt. Because of the mostly benign nature of this disease, the symptomatic recurrence of such incompletely resected mature teratomas is slow and may eventually require a second surgical procedure. The relevant literature is also reviewed.