Sacrococcygeal myxopapillary ependymomas and ependymal rests in infants and children.

The occurrence of sacrococcygeal myxopapillary ependymal tissue appears to be exceedingly rare. We report on five cases of this lesion in infants, four of which occurred in the first year of life. These cases, the youngest on record, should be added to the thirteen cases previously reported. The lesions were completely removed, and the patients have been followed without recurrence for five months to six years. These lesions arise from the coccygeal medullary vestige, which corresponds to the original site of the final closure of the posterior neuropore. The unique embryology of this region can account for the presence of sacrococcygeal teratomas, lipomas, chordomas, as well as the above described lesion. The presence of ependymal rests, as described by Bale, in most patients with postanal dimples, suggests that the incidence of this lesion should be greater. This lesion has a potential for lymph node and pulmonary metastasis and when clinically palpable, should be completely excised.