A variety of lesions of ectodermal, mesodermal, (rarely) endodermal, or mixed-cell layer origin involve the region of the conus medullaris. Some of these abnormalities produce cord tethering and others, such as lipoma, frequently present as masses. In the present case, an infant was discovered to have a lesion most closely resembling a capillary hemangioma involving the skin of the midline and right buttock, the deep soft tissues of the right buttock, the dura, and the conus medullaris. The origin of this congenital spinal tumor from primitive mesoderm is proposed in light of its metameric pattern of distribution.