Spinal neurenteric cysts without associated malformations. Are they the same as those presenting in spinal dysraphism?

Spinal neurenteric cysts are rare intradural developmental lesions, usually composed of a thin-walled cyst whose lining mimicks gastro-intestinal or respiratory epithelium. A detailed review of the literature revealed 80 cases of solitary spinal neurenteric cysts (including a new case of ours), which were analysed and compared, regarding clinical and pathological aspects, with 56 such cases of those with concomitant evidence of dysraphism. Older age and cervical location were found to be statistically characteristic of the solitary cysts in contrast to younger age and lumbosarcal location for the 'dysraphic' cases. Magnetic resonance imaging is the diagnostic modality of choice. Good evidence of the developmental origin of incomplete separation of notochord and endoderm was given by the fact that histologically solitary cysts were mainly composed by endodermal derivatives, while 'dysraphic' had also mesenchymal and ectodermal elements. Thus, it seems that additional spinal dysraphic changes are more likely to be found when ectodermal and mesenchymal elements co-exist with endodermal ones, possibly indicating an earlier error in development than in other cases containing only endodermal elements.